From da3593d859acbe09225c32f8346fe3dc189aa081 Mon Sep 17 00:00:00 2001
From: hpinkos <pinkos.hannah@gmail.com>
Date: Tue, 12 Jun 2018 11:02:26 -0400
Subject: [PATCH 01/12] Better billboard depth test against terrain for clamped
 to ground

---
 Source/Scene/Billboard.js                 |   6 +-
 Source/Scene/BillboardCollection.js       | 154 +++++++++++++++++++++-
 Source/Scene/LabelCollection.js           |  19 ++-
 Source/Shaders/BillboardCollectionFS.glsl |  54 +++++++-
 Source/Shaders/BillboardCollectionVS.glsl |  53 ++++++++
 5 files changed, 272 insertions(+), 14 deletions(-)

diff --git a/Source/Scene/Billboard.js b/Source/Scene/Billboard.js
index df8ad223d024..9fe78e54580c 100644
--- a/Source/Scene/Billboard.js
+++ b/Source/Scene/Billboard.js
@@ -159,6 +159,8 @@ define([
         this._imageWidth = undefined;
         this._imageHeight = undefined;
 
+        this._labelDimensions = undefined;
+
         var image = options.image;
         var imageId = options.imageId;
         if (defined(image)) {
@@ -210,7 +212,9 @@ define([
     var PIXEL_OFFSET_SCALE_BY_DISTANCE_INDEX = Billboard.PIXEL_OFFSET_SCALE_BY_DISTANCE_INDEX = 13;
     var DISTANCE_DISPLAY_CONDITION = Billboard.DISTANCE_DISPLAY_CONDITION = 14;
     var DISABLE_DEPTH_DISTANCE = Billboard.DISABLE_DEPTH_DISTANCE = 15;
-    Billboard.NUMBER_OF_PROPERTIES = 16;
+    Billboard.TEXTURE_OFFSET = 16;
+    Billboard.DIMENSIONS = 17;
+    Billboard.NUMBER_OF_PROPERTIES = 18;
 
     function makeDirty(billboard, propertyChanged) {
         var billboardCollection = billboard._billboardCollection;
diff --git a/Source/Scene/BillboardCollection.js b/Source/Scene/BillboardCollection.js
index 2382486d757a..2e9c17688580 100644
--- a/Source/Scene/BillboardCollection.js
+++ b/Source/Scene/BillboardCollection.js
@@ -84,8 +84,10 @@ define([
     var SCALE_BY_DISTANCE_INDEX = Billboard.SCALE_BY_DISTANCE_INDEX;
     var TRANSLUCENCY_BY_DISTANCE_INDEX = Billboard.TRANSLUCENCY_BY_DISTANCE_INDEX;
     var PIXEL_OFFSET_SCALE_BY_DISTANCE_INDEX = Billboard.PIXEL_OFFSET_SCALE_BY_DISTANCE_INDEX;
-    var DISTANCE_DISPLAY_CONDITION_INDEX = Billboard.DISTANCE_DISPLAY_CONDITION_INDEX;
+    var DISTANCE_DISPLAY_CONDITION_INDEX = Billboard.DISTANCE_DISPLAY_CONDITION;
     var DISABLE_DEPTH_DISTANCE = Billboard.DISABLE_DEPTH_DISTANCE;
+    var TEXTURE_OFFSET = Billboard.TEXTURE_OFFSET;
+    var DIMENSIONS = Billboard.DIMENSIONS;
     var NUMBER_OF_PROPERTIES = Billboard.NUMBER_OF_PROPERTIES;
 
     var attributeLocations;
@@ -100,7 +102,9 @@ define([
         scaleByDistance : 6,
         pixelOffsetScaleByDistance : 7,
         distanceDisplayConditionAndDisableDepth : 8,
-        a_batchId : 9
+        textureOffset : 9,
+        dimensions : 10,
+        a_batchId : 11
     };
 
     var attributeLocationsInstanced = {
@@ -114,7 +118,9 @@ define([
         scaleByDistance : 7,
         pixelOffsetScaleByDistance : 8,
         distanceDisplayConditionAndDisableDepth : 9,
-        a_batchId : 10
+        textureOffset : 10,
+        dimensions : 11,
+        a_batchId : 12
     };
 
     /**
@@ -208,6 +214,9 @@ define([
         this._shaderDisableDepthDistance = false;
         this._compiledShaderDisableDepthDistance = false;
 
+        this._shaderClampToGround = false;
+        this._compiledShaderClampToGround = false;
+
         this._propertiesChanged = new Uint32Array(NUMBER_OF_PROPERTIES);
 
         this._maxSize = 0.0;
@@ -302,7 +311,9 @@ define([
             BufferUsage.STATIC_DRAW, // SCALE_BY_DISTANCE_INDEX
             BufferUsage.STATIC_DRAW, // TRANSLUCENCY_BY_DISTANCE_INDEX
             BufferUsage.STATIC_DRAW, // PIXEL_OFFSET_SCALE_BY_DISTANCE_INDEX
-            BufferUsage.STATIC_DRAW  // DISTANCE_DISPLAY_CONDITION_INDEX
+            BufferUsage.STATIC_DRAW, // DISTANCE_DISPLAY_CONDITION_INDEX
+            BufferUsage.STATIC_DRAW,  // TEXTURE_OFFSET
+            BufferUsage.STATIC_DRAW  // DIMENSIONS
         ];
 
         this._highlightColor = Color.clone(Color.WHITE); // Only used by Vector3DTilePoints
@@ -736,6 +747,16 @@ define([
             componentsPerAttribute : 3,
             componentDatatype : ComponentDatatype.FLOAT,
             usage : buffersUsage[DISTANCE_DISPLAY_CONDITION_INDEX]
+        }, {
+            index : attributeLocations.textureOffset,
+            componentsPerAttribute : 4,
+            componentDatatype : ComponentDatatype.FLOAT,
+            usage : buffersUsage[TEXTURE_OFFSET]
+        }, {
+            index : attributeLocations.dimensions,
+            componentsPerAttribute : 2,
+            componentDatatype : ComponentDatatype.FLOAT,
+            usage : buffersUsage[DIMENSIONS]
         }];
 
         // Instancing requires one non-instanced attribute.
@@ -1176,6 +1197,10 @@ define([
         }
 
         var disableDepthTestDistance = billboard.disableDepthTestDistance;
+        if (billboard.heightReference === HeightReference.CLAMP_TO_GROUND && disableDepthTestDistance === 0.0) {
+            disableDepthTestDistance = 2000.0;
+        }
+
         disableDepthTestDistance *= disableDepthTestDistance;
         if (disableDepthTestDistance > 0.0) {
             billboardCollection._shaderDisableDepthDistance = true;
@@ -1196,6 +1221,96 @@ define([
         }
     }
 
+    function writeTextureOffset(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard) {
+        if (billboard.heightReference === HeightReference.CLAMP_TO_GROUND) {
+            billboardCollection._shaderClampToGround = true;
+        }
+        var i;
+        var writer = vafWriters[attributeLocations.textureOffset];
+
+        var minX = 0;
+        var minY = 0;
+        var width = 0;
+        var height = 0;
+        var index = billboard._imageIndex;
+        if (index !== -1) {
+            var imageRectangle = textureAtlasCoordinates[index];
+
+            //>>includeStart('debug', pragmas.debug);
+            if (!defined(imageRectangle)) {
+                throw new DeveloperError('Invalid billboard image index: ' + index);
+            }
+            //>>includeEnd('debug');
+
+            minX = imageRectangle.x;
+            minY = imageRectangle.y;
+            width = imageRectangle.width;
+            height = imageRectangle.height;
+        }
+        var maxX = minX + width;
+        var maxY = minY + height;
+
+        if (billboardCollection._instanced) {
+            i = billboard._index;
+            writer(i, minX, minY, maxX, maxY);
+        } else {
+            i = billboard._index * 4;
+            writer(i + 0, minX, minY, maxX, maxY);
+            writer(i + 1, minX, minY, maxX, maxY);
+            writer(i + 2, minX, minY, maxX, maxY);
+            writer(i + 3, minX, minY, maxX, maxY);
+        }
+    }
+
+    function writeDimensions(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard) {
+        if (billboard.heightReference === HeightReference.CLAMP_TO_GROUND) {
+            billboardCollection._shaderClampToGround = true;
+        }
+        var i;
+        var writer = vafWriters[attributeLocations.dimensions];
+
+        var imageHeight;
+        var imageWidth;
+
+        if (!defined(billboard._labelDimensions)) {
+            var height = 0;
+            var width = 0;
+            var index = billboard._imageIndex;
+            if (index !== -1) {
+                var imageRectangle = textureAtlasCoordinates[index];
+
+                //>>includeStart('debug', pragmas.debug);
+                if (!defined(imageRectangle)) {
+                    throw new DeveloperError('Invalid billboard image index: ' + index);
+                }
+                //>>includeEnd('debug');
+
+                height = imageRectangle.height;
+                width = imageRectangle.width;
+            }
+
+            var dimensions = billboardCollection._textureAtlas.texture.dimensions;
+            imageHeight = Math.round(defaultValue(billboard.height, dimensions.y * height));
+
+            var textureWidth = billboardCollection._textureAtlas.texture.width;
+            imageWidth = Math.round(defaultValue(billboard.width, textureWidth * width));
+        } else {
+            imageWidth = billboard._labelDimensions.x;
+            imageHeight = billboard._labelDimensions.y;
+        }
+
+        if (billboardCollection._instanced) {
+            i = billboard._index;
+            writer(i, imageWidth, imageHeight);
+        } else {
+            i = billboard._index * 2;
+            writer(i + 0, imageWidth, imageHeight);
+            writer(i + 1, imageWidth, imageHeight);
+            writer(i + 2, imageWidth, imageHeight);
+            writer(i + 3, imageWidth, imageHeight);
+        }
+    }
+
     function writeBatchId(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard) {
         if (!defined(billboardCollection._batchTable)) {
             return;
@@ -1226,6 +1341,8 @@ define([
         writeScaleByDistance(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard);
         writePixelOffsetScaleByDistance(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard);
         writeDistanceDisplayConditionAndDepthDisable(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard);
+        writeTextureOffset(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard);
+        writeDimensions(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard);
         writeBatchId(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard);
     }
 
@@ -1421,10 +1538,18 @@ define([
                 writers.push(writePixelOffsetScaleByDistance);
             }
 
-            if (properties[DISTANCE_DISPLAY_CONDITION_INDEX] || properties[DISABLE_DEPTH_DISTANCE]) {
+            if (properties[DISTANCE_DISPLAY_CONDITION_INDEX] || properties[DISABLE_DEPTH_DISTANCE] || properties[POSITION_INDEX]) {
                 writers.push(writeDistanceDisplayConditionAndDepthDisable);
             }
 
+            if (properties[IMAGE_INDEX_INDEX] || properties[POSITION_INDEX]) {
+                writers.push(writeTextureOffset);
+            }
+
+            if (properties[IMAGE_INDEX_INDEX] || properties[POSITION_INDEX]) {
+                writers.push(writeDimensions);
+            }
+
             var numWriters = writers.length;
             vafWriters = this._vaf.writers;
 
@@ -1540,7 +1665,8 @@ define([
             (this._shaderTranslucencyByDistance !== this._compiledShaderTranslucencyByDistance) ||
             (this._shaderPixelOffsetScaleByDistance !== this._compiledShaderPixelOffsetScaleByDistance) ||
             (this._shaderDistanceDisplayCondition !== this._compiledShaderDistanceDisplayCondition) ||
-            (this._shaderDisableDepthDistance !== this._compiledShaderDisableDepthDistance)) {
+            (this._shaderDisableDepthDistance !== this._compiledShaderDisableDepthDistance) ||
+            (this._shaderClampToGround !== this._compiledShaderClampToGround)) {
 
             vsSource = BillboardCollectionVS;
             fsSource = BillboardCollectionFS;
@@ -1580,6 +1706,9 @@ define([
             if (this._shaderDisableDepthDistance) {
                 vs.defines.push('DISABLE_DEPTH_DISTANCE');
             }
+            if (this._shaderClampToGround) {
+                vs.defines.push('CLAMP_TO_GROUND');
+            }
 
             var vectorFragDefine = defined(this._batchTable) ? 'VECTOR_TILE' : '';
 
@@ -1588,6 +1717,9 @@ define([
                     defines : ['OPAQUE', vectorFragDefine],
                     sources : [fsSource]
                 });
+                if (this._shaderClampToGround) {
+                    fs.defines.push('CLAMP_TO_GROUND');
+                }
                 this._sp = ShaderProgram.replaceCache({
                     context : context,
                     shaderProgram : this._sp,
@@ -1600,6 +1732,9 @@ define([
                     defines : ['TRANSLUCENT', vectorFragDefine],
                     sources : [fsSource]
                 });
+                if (this._shaderClampToGround) {
+                    fs.defines.push('CLAMP_TO_GROUND');
+                }
                 this._spTranslucent = ShaderProgram.replaceCache({
                     context : context,
                     shaderProgram : this._spTranslucent,
@@ -1614,6 +1749,9 @@ define([
                     defines : [vectorFragDefine],
                     sources : [fsSource]
                 });
+                if (this._shaderClampToGround) {
+                    fs.defines.push('CLAMP_TO_GROUND');
+                }
                 this._sp = ShaderProgram.replaceCache({
                     context : context,
                     shaderProgram : this._sp,
@@ -1628,6 +1766,9 @@ define([
                     defines : [vectorFragDefine],
                     sources : [fsSource]
                 });
+                if (this._shaderClampToGround) {
+                    fs.defines.push('CLAMP_TO_GROUND');
+                }
                 this._spTranslucent = ShaderProgram.replaceCache({
                     context : context,
                     shaderProgram : this._spTranslucent,
@@ -1644,6 +1785,7 @@ define([
             this._compiledShaderPixelOffsetScaleByDistance = this._shaderPixelOffsetScaleByDistance;
             this._compiledShaderDistanceDisplayCondition = this._shaderDistanceDisplayCondition;
             this._compiledShaderDisableDepthDistance = this._shaderDisableDepthDistance;
+            this._compiledShaderClampToGround = this._shaderClampToGround;
         }
 
         var commandList = frameState.commandList;
diff --git a/Source/Scene/LabelCollection.js b/Source/Scene/LabelCollection.js
index 5cdfa70bfee0..049810abdf32 100644
--- a/Source/Scene/LabelCollection.js
+++ b/Source/Scene/LabelCollection.js
@@ -249,6 +249,7 @@ define([
                         billboard = labelCollection._billboardCollection.add({
                             collection : labelCollection
                         });
+                        billboard._labelDimensions = new Cartesian2();
                     }
                     glyph.billboard = billboard;
                 }
@@ -306,10 +307,9 @@ define([
         var glyphLength = glyphs.length;
 
         var backgroundBillboard = label._backgroundBillboard;
-        var backgroundPadding = scratchBackgroundPadding;
-        Cartesian2.clone(
+        var backgroundPadding = Cartesian2.clone(
             (defined(backgroundBillboard) ? label._backgroundPadding : Cartesian2.ZERO),
-            backgroundPadding);
+            scratchBackgroundPadding);
 
         for (glyphIndex = 0; glyphIndex < glyphLength; ++glyphIndex) {
             if (text.charAt(glyphIndex) === '\n') {
@@ -341,6 +341,13 @@ define([
         var widthOffset = calculateWidthOffset(lineWidth, horizontalOrigin, backgroundPadding);
         var lineSpacing = defaultLineSpacingPercent * maxLineHeight;
         var otherLinesHeight = lineSpacing * (numberOfLines - 1);
+        var totalLineWidth = maxLineWidth;
+        var totalLineHeight = maxLineHeight + otherLinesHeight;
+
+        if (defined(backgroundBillboard)) {
+            totalLineWidth += (backgroundPadding.x * 2);
+            totalLineHeight += (backgroundPadding.y * 2);
+        }
 
         glyphPixelOffset.x = widthOffset * scale * resolutionScale;
         glyphPixelOffset.y = 0;
@@ -371,6 +378,8 @@ define([
 
                 if (defined(glyph.billboard)) {
                     glyph.billboard._setTranslate(glyphPixelOffset);
+                    glyph.billboard._labelDimensions.x = totalLineWidth;
+                    glyph.billboard._labelDimensions.y = totalLineHeight;
                 }
 
                 //Compute the next x offset taking into acocunt the kerning performed
@@ -405,8 +414,8 @@ define([
             }
             glyphPixelOffset.y = glyphPixelOffset.y * scale * resolutionScale;
 
-            backgroundBillboard.width = maxLineWidth + (backgroundPadding.x * 2);
-            backgroundBillboard.height = maxLineHeight + otherLinesHeight + (backgroundPadding.y * 2);
+            backgroundBillboard.width = totalLineWidth;
+            backgroundBillboard.height = totalLineHeight;
             backgroundBillboard._setTranslate(glyphPixelOffset);
         }
     }
diff --git a/Source/Shaders/BillboardCollectionFS.glsl b/Source/Shaders/BillboardCollectionFS.glsl
index 6d9a66cdcb7d..6fd371c897f0 100644
--- a/Source/Shaders/BillboardCollectionFS.glsl
+++ b/Source/Shaders/BillboardCollectionFS.glsl
@@ -5,10 +5,40 @@ uniform vec4 u_highlightColor;
 #endif
 
 varying vec2 v_textureCoordinates;
-
 varying vec4 v_pickColor;
 varying vec4 v_color;
 
+#ifdef CLAMP_TO_GROUND
+varying vec4 v_textureOffset;
+varying vec2 v_originTextureCoordinate;
+varying vec2 v_leftTextureCoordinate;
+varying vec2 v_rightTextureCoordinate;
+varying vec2 v_dimensions;
+varying vec2 v_imageSize;
+varying vec2 v_translate;
+varying float v_eyeDepth;
+varying float v_disableDepthTestDistance;
+
+float getGlobeDepth(vec2 adjustedST, vec2 depthLookupST)
+{
+    vec2 a = v_imageSize.xy * (depthLookupST - adjustedST);
+    vec2 Dd = v_dimensions - v_imageSize;
+    vec2 px = v_translate.xy + (v_dimensions * v_originTextureCoordinate * vec2(0, -1)); // this is only needed for labels
+
+    vec2 st = ((a - px + (depthLookupST * Dd)) + gl_FragCoord.xy) / czm_viewport.zw;
+
+    float logDepthOrDepth = czm_unpackDepth(texture2D(czm_globeDepthTexture, st));
+
+    if (logDepthOrDepth == 0.0)
+    {
+        return 0.0;
+    }
+
+    vec4 eyeCoordinate = czm_windowToEyeCoordinates(gl_FragCoord.xy, logDepthOrDepth);
+    return eyeCoordinate.z / eyeCoordinate.w;
+}
+#endif
+
 void main()
 {
     vec4 color = texture2D(u_atlas, v_textureCoordinates) * v_color;
@@ -38,7 +68,27 @@ void main()
 #ifdef VECTOR_TILE
     color *= u_highlightColor;
 #endif
-
     gl_FragColor = color;
+
     czm_writeLogDepth();
+
+#ifdef CLAMP_TO_GROUND
+    if (v_eyeDepth > -v_disableDepthTestDistance) {
+        vec2 adjustedST = v_textureCoordinates - v_textureOffset.xy;
+        adjustedST = adjustedST / vec2(v_textureOffset.z - v_textureOffset.x, v_textureOffset.w - v_textureOffset.y);
+
+        float globeDepth1 = getGlobeDepth(adjustedST, v_originTextureCoordinate);
+        float globeDepth2 = getGlobeDepth(adjustedST, v_leftTextureCoordinate);
+        float globeDepth3 = getGlobeDepth(adjustedST, v_rightTextureCoordinate);
+
+        float epsilonEyeDepth = v_eyeDepth + czm_epsilon5;
+
+        // negative values go into the screen
+        if (globeDepth1 > epsilonEyeDepth && globeDepth2 > epsilonEyeDepth && globeDepth3 > epsilonEyeDepth)
+        {
+            discard;
+        }
+    }
+#endif
+
 }
diff --git a/Source/Shaders/BillboardCollectionVS.glsl b/Source/Shaders/BillboardCollectionVS.glsl
index 9c6f537e5856..e0f10233e967 100644
--- a/Source/Shaders/BillboardCollectionVS.glsl
+++ b/Source/Shaders/BillboardCollectionVS.glsl
@@ -10,11 +10,26 @@ attribute vec4 eyeOffset;                                  // eye offset in mete
 attribute vec4 scaleByDistance;                            // near, nearScale, far, farScale
 attribute vec4 pixelOffsetScaleByDistance;                 // near, nearScale, far, farScale
 attribute vec3 distanceDisplayConditionAndDisableDepth;    // near, far, disableDepthTestDistance
+#ifdef CLAMP_TO_GROUND
+attribute vec4 textureOffset;                              // the min and max x and y values for the texture coordinates
+attribute vec2 dimensions;
+#endif
 #ifdef VECTOR_TILE
 attribute float a_batchId;
 #endif
 
 varying vec2 v_textureCoordinates;
+#ifdef CLAMP_TO_GROUND
+varying vec4 v_textureOffset;
+varying vec2 v_originTextureCoordinate;
+varying vec2 v_leftTextureCoordinate;
+varying vec2 v_rightTextureCoordinate;
+varying vec2 v_dimensions;
+varying vec2 v_imageSize;
+varying vec2 v_translate;
+varying float v_eyeDepth;
+varying float v_disableDepthTestDistance;
+#endif
 
 varying vec4 v_pickColor;
 varying vec4 v_color;
@@ -116,6 +131,9 @@ void main()
     origin.y = floor(compressed * SHIFT_RIGHT3);
     compressed -= origin.y * SHIFT_LEFT3;
 
+#ifdef CLAMP_TO_GROUND
+    vec2 depthOrigin = origin.xy * 0.5;
+#endif
     origin -= vec2(1.0);
 
     float show = floor(compressed * SHIFT_RIGHT2);
@@ -145,10 +163,34 @@ void main()
     translate.y += (temp - floor(temp)) * SHIFT_LEFT8;
     translate.y -= UPPER_BOUND;
 
+    v_translate = translate.xy;
+
     temp = compressedAttribute1.x * SHIFT_RIGHT8;
 
     vec2 imageSize = vec2(floor(temp), compressedAttribute2.w);
 
+#ifdef CLAMP_TO_GROUND
+    v_textureOffset = textureOffset;
+    v_originTextureCoordinate = vec2(1.0) - depthOrigin; //the origin
+    if (v_originTextureCoordinate.y == 1.0) //vertical origin is top
+    {
+        v_leftTextureCoordinate = vec2(0.0, 0.0); //bottom left
+        v_rightTextureCoordinate = vec2(1.0, 0.0); //bottom right
+    }
+    else
+    {
+        if (v_originTextureCoordinate.y == 0.0)
+        {
+            v_originTextureCoordinate.y = 0.1;
+        }
+
+        v_leftTextureCoordinate = vec2(0.0, 1.0); //top left
+        v_rightTextureCoordinate = vec2(1.0, 1.0); //top right
+    }
+    v_dimensions = dimensions.xy;
+    v_imageSize = imageSize.xy;
+#endif
+
 #ifdef EYE_DISTANCE_TRANSLUCENCY
     vec4 translucencyByDistance;
     translucencyByDistance.x = compressedAttribute1.z;
@@ -200,6 +242,11 @@ void main()
 
     vec4 p = czm_translateRelativeToEye(positionHigh, positionLow);
     vec4 positionEC = czm_modelViewRelativeToEye * p;
+
+#ifdef CLAMP_TO_GROUND
+    v_eyeDepth = positionEC.z;
+#endif
+
     positionEC = czm_eyeOffset(positionEC, eyeOffset.xyz);
     positionEC.xyz *= show;
 
@@ -264,6 +311,11 @@ void main()
 
 #ifdef DISABLE_DEPTH_DISTANCE
     float disableDepthTestDistance = distanceDisplayConditionAndDisableDepth.z;
+
+    #ifdef CLAMP_TO_GROUND
+    v_disableDepthTestDistance = disableDepthTestDistance;
+    #endif
+
     if (disableDepthTestDistance == 0.0 && czm_minimumDisableDepthTestDistance != 0.0)
     {
         disableDepthTestDistance = czm_minimumDisableDepthTestDistance;
@@ -289,4 +341,5 @@ void main()
 
     v_color = color;
     v_color.a *= translucency;
+
 }

From bd633129449d15508b73dca13a7733607c48d87c Mon Sep 17 00:00:00 2001
From: hpinkos <pinkos.hannah@gmail.com>
Date: Tue, 12 Jun 2018 12:47:46 -0400
Subject: [PATCH 02/12] cleanup

---
 Source/Scene/Billboard.js                 |  2 +-
 Source/Scene/BillboardCollection.js       | 20 ++++++++++----------
 Source/Shaders/BillboardCollectionFS.glsl | 23 ++++++++++++++---------
 Source/Shaders/BillboardCollectionVS.glsl | 10 +++++-----
 4 files changed, 30 insertions(+), 25 deletions(-)

diff --git a/Source/Scene/Billboard.js b/Source/Scene/Billboard.js
index 9fe78e54580c..49cbfa7fb011 100644
--- a/Source/Scene/Billboard.js
+++ b/Source/Scene/Billboard.js
@@ -212,7 +212,7 @@ define([
     var PIXEL_OFFSET_SCALE_BY_DISTANCE_INDEX = Billboard.PIXEL_OFFSET_SCALE_BY_DISTANCE_INDEX = 13;
     var DISTANCE_DISPLAY_CONDITION = Billboard.DISTANCE_DISPLAY_CONDITION = 14;
     var DISABLE_DEPTH_DISTANCE = Billboard.DISABLE_DEPTH_DISTANCE = 15;
-    Billboard.TEXTURE_OFFSET = 16;
+    Billboard.TEXTURE_COORDINATE_BOUNDS = 16;
     Billboard.DIMENSIONS = 17;
     Billboard.NUMBER_OF_PROPERTIES = 18;
 
diff --git a/Source/Scene/BillboardCollection.js b/Source/Scene/BillboardCollection.js
index 2e9c17688580..fa6c4a30fd19 100644
--- a/Source/Scene/BillboardCollection.js
+++ b/Source/Scene/BillboardCollection.js
@@ -86,7 +86,7 @@ define([
     var PIXEL_OFFSET_SCALE_BY_DISTANCE_INDEX = Billboard.PIXEL_OFFSET_SCALE_BY_DISTANCE_INDEX;
     var DISTANCE_DISPLAY_CONDITION_INDEX = Billboard.DISTANCE_DISPLAY_CONDITION;
     var DISABLE_DEPTH_DISTANCE = Billboard.DISABLE_DEPTH_DISTANCE;
-    var TEXTURE_OFFSET = Billboard.TEXTURE_OFFSET;
+    var TEXTURE_COORDINATE_BOUNDS = Billboard.TEXTURE_COORDINATE_BOUNDS;
     var DIMENSIONS = Billboard.DIMENSIONS;
     var NUMBER_OF_PROPERTIES = Billboard.NUMBER_OF_PROPERTIES;
 
@@ -102,7 +102,7 @@ define([
         scaleByDistance : 6,
         pixelOffsetScaleByDistance : 7,
         distanceDisplayConditionAndDisableDepth : 8,
-        textureOffset : 9,
+        textureCoordinateBounds : 9,
         dimensions : 10,
         a_batchId : 11
     };
@@ -118,7 +118,7 @@ define([
         scaleByDistance : 7,
         pixelOffsetScaleByDistance : 8,
         distanceDisplayConditionAndDisableDepth : 9,
-        textureOffset : 10,
+        textureCoordinateBounds : 10,
         dimensions : 11,
         a_batchId : 12
     };
@@ -312,7 +312,7 @@ define([
             BufferUsage.STATIC_DRAW, // TRANSLUCENCY_BY_DISTANCE_INDEX
             BufferUsage.STATIC_DRAW, // PIXEL_OFFSET_SCALE_BY_DISTANCE_INDEX
             BufferUsage.STATIC_DRAW, // DISTANCE_DISPLAY_CONDITION_INDEX
-            BufferUsage.STATIC_DRAW,  // TEXTURE_OFFSET
+            BufferUsage.STATIC_DRAW, // TEXTURE_COORDINATE_BOUNDS
             BufferUsage.STATIC_DRAW  // DIMENSIONS
         ];
 
@@ -748,10 +748,10 @@ define([
             componentDatatype : ComponentDatatype.FLOAT,
             usage : buffersUsage[DISTANCE_DISPLAY_CONDITION_INDEX]
         }, {
-            index : attributeLocations.textureOffset,
+            index : attributeLocations.textureCoordinateBounds,
             componentsPerAttribute : 4,
             componentDatatype : ComponentDatatype.FLOAT,
-            usage : buffersUsage[TEXTURE_OFFSET]
+            usage : buffersUsage[TEXTURE_COORDINATE_BOUNDS]
         }, {
             index : attributeLocations.dimensions,
             componentsPerAttribute : 2,
@@ -1221,12 +1221,12 @@ define([
         }
     }
 
-    function writeTextureOffset(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard) {
+    function writeTextureCoordinateBounds(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard) {
         if (billboard.heightReference === HeightReference.CLAMP_TO_GROUND) {
             billboardCollection._shaderClampToGround = true;
         }
         var i;
-        var writer = vafWriters[attributeLocations.textureOffset];
+        var writer = vafWriters[attributeLocations.textureCoordinateBounds];
 
         var minX = 0;
         var minY = 0;
@@ -1341,7 +1341,7 @@ define([
         writeScaleByDistance(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard);
         writePixelOffsetScaleByDistance(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard);
         writeDistanceDisplayConditionAndDepthDisable(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard);
-        writeTextureOffset(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard);
+        writeTextureCoordinateBounds(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard);
         writeDimensions(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard);
         writeBatchId(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard);
     }
@@ -1543,7 +1543,7 @@ define([
             }
 
             if (properties[IMAGE_INDEX_INDEX] || properties[POSITION_INDEX]) {
-                writers.push(writeTextureOffset);
+                writers.push(writeTextureCoordinateBounds);
             }
 
             if (properties[IMAGE_INDEX_INDEX] || properties[POSITION_INDEX]) {
diff --git a/Source/Shaders/BillboardCollectionFS.glsl b/Source/Shaders/BillboardCollectionFS.glsl
index 6fd371c897f0..1c19328e01e2 100644
--- a/Source/Shaders/BillboardCollectionFS.glsl
+++ b/Source/Shaders/BillboardCollectionFS.glsl
@@ -9,7 +9,7 @@ varying vec4 v_pickColor;
 varying vec4 v_color;
 
 #ifdef CLAMP_TO_GROUND
-varying vec4 v_textureOffset;
+varying vec4 v_textureCoordinateBounds;
 varying vec2 v_originTextureCoordinate;
 varying vec2 v_leftTextureCoordinate;
 varying vec2 v_rightTextureCoordinate;
@@ -74,19 +74,24 @@ void main()
 
 #ifdef CLAMP_TO_GROUND
     if (v_eyeDepth > -v_disableDepthTestDistance) {
-        vec2 adjustedST = v_textureCoordinates - v_textureOffset.xy;
-        adjustedST = adjustedST / vec2(v_textureOffset.z - v_textureOffset.x, v_textureOffset.w - v_textureOffset.y);
-
-        float globeDepth1 = getGlobeDepth(adjustedST, v_originTextureCoordinate);
-        float globeDepth2 = getGlobeDepth(adjustedST, v_leftTextureCoordinate);
-        float globeDepth3 = getGlobeDepth(adjustedST, v_rightTextureCoordinate);
+        vec2 adjustedST = v_textureCoordinates - v_textureCoordinateBounds.xy;
+        adjustedST = adjustedST / vec2(v_textureCoordinateBounds.z - v_textureCoordinateBounds.x, v_textureCoordinateBounds.w - v_textureCoordinateBounds.y);
 
         float epsilonEyeDepth = v_eyeDepth + czm_epsilon5;
+        float globeDepth1 = getGlobeDepth(adjustedST, v_originTextureCoordinate);
 
         // negative values go into the screen
-        if (globeDepth1 > epsilonEyeDepth && globeDepth2 > epsilonEyeDepth && globeDepth3 > epsilonEyeDepth)
+        if (globeDepth1 > epsilonEyeDepth)
         {
-            discard;
+            float globeDepth2 = getGlobeDepth(adjustedST, v_leftTextureCoordinate);
+            if (globeDepth2 > epsilonEyeDepth)
+            {
+                float globeDepth3 = getGlobeDepth(adjustedST, v_rightTextureCoordinate);
+                if (globeDepth3 > epsilonEyeDepth)
+                {
+                    discard;
+                }
+            }
         }
     }
 #endif
diff --git a/Source/Shaders/BillboardCollectionVS.glsl b/Source/Shaders/BillboardCollectionVS.glsl
index e0f10233e967..8c38fd9dc46f 100644
--- a/Source/Shaders/BillboardCollectionVS.glsl
+++ b/Source/Shaders/BillboardCollectionVS.glsl
@@ -11,7 +11,7 @@ attribute vec4 scaleByDistance;                            // near, nearScale, f
 attribute vec4 pixelOffsetScaleByDistance;                 // near, nearScale, far, farScale
 attribute vec3 distanceDisplayConditionAndDisableDepth;    // near, far, disableDepthTestDistance
 #ifdef CLAMP_TO_GROUND
-attribute vec4 textureOffset;                              // the min and max x and y values for the texture coordinates
+attribute vec4 textureCoordinateBounds;                              // the min and max x and y values for the texture coordinates
 attribute vec2 dimensions;
 #endif
 #ifdef VECTOR_TILE
@@ -20,7 +20,7 @@ attribute float a_batchId;
 
 varying vec2 v_textureCoordinates;
 #ifdef CLAMP_TO_GROUND
-varying vec4 v_textureOffset;
+varying vec4 v_textureCoordinateBounds;
 varying vec2 v_originTextureCoordinate;
 varying vec2 v_leftTextureCoordinate;
 varying vec2 v_rightTextureCoordinate;
@@ -170,11 +170,11 @@ void main()
     vec2 imageSize = vec2(floor(temp), compressedAttribute2.w);
 
 #ifdef CLAMP_TO_GROUND
-    v_textureOffset = textureOffset;
+    v_textureCoordinateBounds = textureCoordinateBounds;
     v_originTextureCoordinate = vec2(1.0) - depthOrigin; //the origin
     if (v_originTextureCoordinate.y == 1.0) //vertical origin is top
     {
-        v_leftTextureCoordinate = vec2(0.0, 0.0); //bottom left
+        v_leftTextureCoordinate = vec2(0.0); //bottom left
         v_rightTextureCoordinate = vec2(1.0, 0.0); //bottom right
     }
     else
@@ -185,7 +185,7 @@ void main()
         }
 
         v_leftTextureCoordinate = vec2(0.0, 1.0); //top left
-        v_rightTextureCoordinate = vec2(1.0, 1.0); //top right
+        v_rightTextureCoordinate = vec2(1.0); //top right
     }
     v_dimensions = dimensions.xy;
     v_imageSize = imageSize.xy;

From 3f019cc4b19f11da0b774988d9e9feb46ffc432d Mon Sep 17 00:00:00 2001
From: hpinkos <pinkos.hannah@gmail.com>
Date: Tue, 12 Jun 2018 16:59:42 -0400
Subject: [PATCH 03/12] compress the things

---
 Source/Scene/Billboard.js                 |   3 +-
 Source/Scene/BillboardCollection.js       | 131 +++++++++-------------
 Source/Shaders/BillboardCollectionFS.glsl |  49 ++++----
 Source/Shaders/BillboardCollectionVS.glsl |  53 +++++----
 4 files changed, 105 insertions(+), 131 deletions(-)

diff --git a/Source/Scene/Billboard.js b/Source/Scene/Billboard.js
index 49cbfa7fb011..52946cd882dc 100644
--- a/Source/Scene/Billboard.js
+++ b/Source/Scene/Billboard.js
@@ -213,8 +213,7 @@ define([
     var DISTANCE_DISPLAY_CONDITION = Billboard.DISTANCE_DISPLAY_CONDITION = 14;
     var DISABLE_DEPTH_DISTANCE = Billboard.DISABLE_DEPTH_DISTANCE = 15;
     Billboard.TEXTURE_COORDINATE_BOUNDS = 16;
-    Billboard.DIMENSIONS = 17;
-    Billboard.NUMBER_OF_PROPERTIES = 18;
+    Billboard.NUMBER_OF_PROPERTIES = 17;
 
     function makeDirty(billboard, propertyChanged) {
         var billboardCollection = billboard._billboardCollection;
diff --git a/Source/Scene/BillboardCollection.js b/Source/Scene/BillboardCollection.js
index fa6c4a30fd19..a0647289f835 100644
--- a/Source/Scene/BillboardCollection.js
+++ b/Source/Scene/BillboardCollection.js
@@ -87,7 +87,6 @@ define([
     var DISTANCE_DISPLAY_CONDITION_INDEX = Billboard.DISTANCE_DISPLAY_CONDITION;
     var DISABLE_DEPTH_DISTANCE = Billboard.DISABLE_DEPTH_DISTANCE;
     var TEXTURE_COORDINATE_BOUNDS = Billboard.TEXTURE_COORDINATE_BOUNDS;
-    var DIMENSIONS = Billboard.DIMENSIONS;
     var NUMBER_OF_PROPERTIES = Billboard.NUMBER_OF_PROPERTIES;
 
     var attributeLocations;
@@ -101,10 +100,9 @@ define([
         eyeOffset : 5,                   // 4 bytes free
         scaleByDistance : 6,
         pixelOffsetScaleByDistance : 7,
-        distanceDisplayConditionAndDisableDepth : 8,
+        compressedAttribute3 : 8,
         textureCoordinateBounds : 9,
-        dimensions : 10,
-        a_batchId : 11
+        a_batchId : 10
     };
 
     var attributeLocationsInstanced = {
@@ -117,10 +115,9 @@ define([
         eyeOffset : 6,                  // texture range in w
         scaleByDistance : 7,
         pixelOffsetScaleByDistance : 8,
-        distanceDisplayConditionAndDisableDepth : 9,
+        compressedAttribute3 : 9,
         textureCoordinateBounds : 10,
-        dimensions : 11,
-        a_batchId : 12
+        a_batchId : 11
     };
 
     /**
@@ -312,8 +309,7 @@ define([
             BufferUsage.STATIC_DRAW, // TRANSLUCENCY_BY_DISTANCE_INDEX
             BufferUsage.STATIC_DRAW, // PIXEL_OFFSET_SCALE_BY_DISTANCE_INDEX
             BufferUsage.STATIC_DRAW, // DISTANCE_DISPLAY_CONDITION_INDEX
-            BufferUsage.STATIC_DRAW, // TEXTURE_COORDINATE_BOUNDS
-            BufferUsage.STATIC_DRAW  // DIMENSIONS
+            BufferUsage.STATIC_DRAW  // TEXTURE_COORDINATE_BOUNDS
         ];
 
         this._highlightColor = Color.clone(Color.WHITE); // Only used by Vector3DTilePoints
@@ -743,8 +739,8 @@ define([
             componentDatatype : ComponentDatatype.FLOAT,
             usage : buffersUsage[PIXEL_OFFSET_SCALE_BY_DISTANCE_INDEX]
         }, {
-            index : attributeLocations.distanceDisplayConditionAndDisableDepth,
-            componentsPerAttribute : 3,
+            index : attributeLocations.compressedAttribute3,
+            componentsPerAttribute : 4,
             componentDatatype : ComponentDatatype.FLOAT,
             usage : buffersUsage[DISTANCE_DISPLAY_CONDITION_INDEX]
         }, {
@@ -752,11 +748,6 @@ define([
             componentsPerAttribute : 4,
             componentDatatype : ComponentDatatype.FLOAT,
             usage : buffersUsage[TEXTURE_COORDINATE_BOUNDS]
-        }, {
-            index : attributeLocations.dimensions,
-            componentsPerAttribute : 2,
-            componentDatatype : ComponentDatatype.FLOAT,
-            usage : buffersUsage[DIMENSIONS]
         }];
 
         // Instancing requires one non-instanced attribute.
@@ -839,6 +830,7 @@ define([
     var UPPER_BOUND = 32768.0;  // 2^15
 
     var LEFT_SHIFT16 = 65536.0; // 2^16
+    var LEFT_SHIFT12 = 4096.0;  // 2^12
     var LEFT_SHIFT8 = 256.0;    // 2^8
     var LEFT_SHIFT7 = 128.0;
     var LEFT_SHIFT5 = 32.0;
@@ -1179,9 +1171,9 @@ define([
         }
     }
 
-    function writeDistanceDisplayConditionAndDepthDisable(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard) {
+    function writeCompressedAttribute3(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard) {
         var i;
-        var writer = vafWriters[attributeLocations.distanceDisplayConditionAndDisableDepth];
+        var writer = vafWriters[attributeLocations.compressedAttribute3];
         var near = 0.0;
         var far = Number.MAX_VALUE;
 
@@ -1209,15 +1201,48 @@ define([
             }
         }
 
+        var imageHeight;
+        var imageWidth;
+
+        if (!defined(billboard._labelDimensions)) {
+            var height = 0;
+            var width = 0;
+            var index = billboard._imageIndex;
+            if (index !== -1) {
+                var imageRectangle = textureAtlasCoordinates[index];
+
+                //>>includeStart('debug', pragmas.debug);
+                if (!defined(imageRectangle)) {
+                    throw new DeveloperError('Invalid billboard image index: ' + index);
+                }
+                //>>includeEnd('debug');
+
+                height = imageRectangle.height;
+                width = imageRectangle.width;
+            }
+
+            imageHeight = Math.round(defaultValue(billboard.height, billboardCollection._textureAtlas.texture.dimensions.y * height));
+
+            var textureWidth = billboardCollection._textureAtlas.texture.width;
+            imageWidth = Math.round(defaultValue(billboard.width, textureWidth * width));
+        } else {
+            imageWidth = billboard._labelDimensions.x;
+            imageHeight = billboard._labelDimensions.y;
+        }
+
+        var w = Math.floor(CesiumMath.clamp(imageWidth, 0.0, LEFT_SHIFT12));
+        var h = Math.floor(CesiumMath.clamp(imageHeight, 0.0, LEFT_SHIFT12));
+        var dimensions = w * LEFT_SHIFT12 + h;
+
         if (billboardCollection._instanced) {
             i = billboard._index;
-            writer(i, near, far, disableDepthTestDistance);
+            writer(i, near, far, disableDepthTestDistance, dimensions);
         } else {
             i = billboard._index * 4;
-            writer(i + 0, near, far, disableDepthTestDistance);
-            writer(i + 1, near, far, disableDepthTestDistance);
-            writer(i + 2, near, far, disableDepthTestDistance);
-            writer(i + 3, near, far, disableDepthTestDistance);
+            writer(i + 0, near, far, disableDepthTestDistance, dimensions);
+            writer(i + 1, near, far, disableDepthTestDistance, dimensions);
+            writer(i + 2, near, far, disableDepthTestDistance, dimensions);
+            writer(i + 3, near, far, disableDepthTestDistance, dimensions);
         }
     }
 
@@ -1262,55 +1287,6 @@ define([
         }
     }
 
-    function writeDimensions(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard) {
-        if (billboard.heightReference === HeightReference.CLAMP_TO_GROUND) {
-            billboardCollection._shaderClampToGround = true;
-        }
-        var i;
-        var writer = vafWriters[attributeLocations.dimensions];
-
-        var imageHeight;
-        var imageWidth;
-
-        if (!defined(billboard._labelDimensions)) {
-            var height = 0;
-            var width = 0;
-            var index = billboard._imageIndex;
-            if (index !== -1) {
-                var imageRectangle = textureAtlasCoordinates[index];
-
-                //>>includeStart('debug', pragmas.debug);
-                if (!defined(imageRectangle)) {
-                    throw new DeveloperError('Invalid billboard image index: ' + index);
-                }
-                //>>includeEnd('debug');
-
-                height = imageRectangle.height;
-                width = imageRectangle.width;
-            }
-
-            var dimensions = billboardCollection._textureAtlas.texture.dimensions;
-            imageHeight = Math.round(defaultValue(billboard.height, dimensions.y * height));
-
-            var textureWidth = billboardCollection._textureAtlas.texture.width;
-            imageWidth = Math.round(defaultValue(billboard.width, textureWidth * width));
-        } else {
-            imageWidth = billboard._labelDimensions.x;
-            imageHeight = billboard._labelDimensions.y;
-        }
-
-        if (billboardCollection._instanced) {
-            i = billboard._index;
-            writer(i, imageWidth, imageHeight);
-        } else {
-            i = billboard._index * 2;
-            writer(i + 0, imageWidth, imageHeight);
-            writer(i + 1, imageWidth, imageHeight);
-            writer(i + 2, imageWidth, imageHeight);
-            writer(i + 3, imageWidth, imageHeight);
-        }
-    }
-
     function writeBatchId(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard) {
         if (!defined(billboardCollection._batchTable)) {
             return;
@@ -1340,9 +1316,8 @@ define([
         writeEyeOffset(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard);
         writeScaleByDistance(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard);
         writePixelOffsetScaleByDistance(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard);
-        writeDistanceDisplayConditionAndDepthDisable(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard);
+        writeCompressedAttribute3(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard);
         writeTextureCoordinateBounds(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard);
-        writeDimensions(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard);
         writeBatchId(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard);
     }
 
@@ -1538,18 +1513,14 @@ define([
                 writers.push(writePixelOffsetScaleByDistance);
             }
 
-            if (properties[DISTANCE_DISPLAY_CONDITION_INDEX] || properties[DISABLE_DEPTH_DISTANCE] || properties[POSITION_INDEX]) {
-                writers.push(writeDistanceDisplayConditionAndDepthDisable);
+            if (properties[DISTANCE_DISPLAY_CONDITION_INDEX] || properties[DISABLE_DEPTH_DISTANCE] || properties[IMAGE_INDEX_INDEX] || properties[POSITION_INDEX]) {
+                writers.push(writeCompressedAttribute3);
             }
 
             if (properties[IMAGE_INDEX_INDEX] || properties[POSITION_INDEX]) {
                 writers.push(writeTextureCoordinateBounds);
             }
 
-            if (properties[IMAGE_INDEX_INDEX] || properties[POSITION_INDEX]) {
-                writers.push(writeDimensions);
-            }
-
             var numWriters = writers.length;
             vafWriters = this._vaf.writers;
 
diff --git a/Source/Shaders/BillboardCollectionFS.glsl b/Source/Shaders/BillboardCollectionFS.glsl
index 1c19328e01e2..2aa8c03e6e50 100644
--- a/Source/Shaders/BillboardCollectionFS.glsl
+++ b/Source/Shaders/BillboardCollectionFS.glsl
@@ -9,29 +9,34 @@ varying vec4 v_pickColor;
 varying vec4 v_color;
 
 #ifdef CLAMP_TO_GROUND
-varying vec4 v_textureCoordinateBounds;
-varying vec2 v_originTextureCoordinate;
-varying vec2 v_leftTextureCoordinate;
-varying vec2 v_rightTextureCoordinate;
-varying vec2 v_dimensions;
-varying vec2 v_imageSize;
-varying vec2 v_translate;
-varying float v_eyeDepth;
-varying float v_disableDepthTestDistance;
+varying vec4 v_textureCoordinateBounds;                  // the min and max x and y values for the texture coordinates
+varying vec4 v_originTextureCoordinateAndTranslate;      // texture coordinate at the origin, billboard translate (used for label glyphs)
+varying vec4 v_leftAndRightTextureCoordinate;            // texture coordinates for left and right depth test
+varying vec4 v_dimensionsAndImageSize;                   // dimensions of the bounding rectangle and the size of the image.  The values will only be different for label glyphs
+varying vec2 v_eyeDepthAndDistance;                      // The depth of the billboard and the disable depth test distance
 
 float getGlobeDepth(vec2 adjustedST, vec2 depthLookupST)
 {
-    vec2 a = v_imageSize.xy * (depthLookupST - adjustedST);
-    vec2 Dd = v_dimensions - v_imageSize;
-    vec2 px = v_translate.xy + (v_dimensions * v_originTextureCoordinate * vec2(0, -1)); // this is only needed for labels
+    vec2 dimensions = v_dimensionsAndImageSize.xy;
+    vec2 imageSize = v_dimensionsAndImageSize.zw;
 
-    vec2 st = ((a - px + (depthLookupST * Dd)) + gl_FragCoord.xy) / czm_viewport.zw;
+    vec2 lookupVector = imageSize * (depthLookupST - adjustedST);
+    vec2 labelOffset = depthLookupST * (dimensions - imageSize); // aligns label glyph with bounding rectangle.  Will be zero for billboards because dimensions and imageSize will be equal
+    vec2 translation = v_originTextureCoordinateAndTranslate.zw;
+    if (translation != vec2(0.0))
+    {
+        // this is only needed for labels where the horizontal origin is not LEFT
+        // it moves the label back to where the "origin" should be since all label glyphs are set to HorizontalOrigin.LEFT
+        translation += (dimensions * v_originTextureCoordinateAndTranslate.xy * vec2(0, -1));
+    }
+
+    vec2 st = ((lookupVector - translation + labelOffset) + gl_FragCoord.xy) / czm_viewport.zw;
 
     float logDepthOrDepth = czm_unpackDepth(texture2D(czm_globeDepthTexture, st));
 
     if (logDepthOrDepth == 0.0)
     {
-        return 0.0;
+        return 0.0; // not on the globe
     }
 
     vec4 eyeCoordinate = czm_windowToEyeCoordinates(gl_FragCoord.xy, logDepthOrDepth);
@@ -73,21 +78,21 @@ void main()
     czm_writeLogDepth();
 
 #ifdef CLAMP_TO_GROUND
-    if (v_eyeDepth > -v_disableDepthTestDistance) {
+    if (v_eyeDepthAndDistance.x > -v_eyeDepthAndDistance.y) {
         vec2 adjustedST = v_textureCoordinates - v_textureCoordinateBounds.xy;
         adjustedST = adjustedST / vec2(v_textureCoordinateBounds.z - v_textureCoordinateBounds.x, v_textureCoordinateBounds.w - v_textureCoordinateBounds.y);
 
-        float epsilonEyeDepth = v_eyeDepth + czm_epsilon5;
-        float globeDepth1 = getGlobeDepth(adjustedST, v_originTextureCoordinate);
+        float epsilonEyeDepth = v_eyeDepthAndDistance.x + czm_epsilon5;
+        float globeDepth1 = getGlobeDepth(adjustedST, v_originTextureCoordinateAndTranslate.xy);
 
         // negative values go into the screen
-        if (globeDepth1 > epsilonEyeDepth)
+        if (globeDepth1 != 0.0 && globeDepth1 > epsilonEyeDepth)
         {
-            float globeDepth2 = getGlobeDepth(adjustedST, v_leftTextureCoordinate);
-            if (globeDepth2 > epsilonEyeDepth)
+            float globeDepth2 = getGlobeDepth(adjustedST, v_leftAndRightTextureCoordinate.xy);
+            if (globeDepth2 != 0.0 && globeDepth2 > epsilonEyeDepth)
             {
-                float globeDepth3 = getGlobeDepth(adjustedST, v_rightTextureCoordinate);
-                if (globeDepth3 > epsilonEyeDepth)
+                float globeDepth3 = getGlobeDepth(adjustedST, v_leftAndRightTextureCoordinate.zw);
+                if (globeDepth3 != 0.0 && globeDepth3 > epsilonEyeDepth)
                 {
                     discard;
                 }
diff --git a/Source/Shaders/BillboardCollectionVS.glsl b/Source/Shaders/BillboardCollectionVS.glsl
index 8c38fd9dc46f..dd5f7c60a19c 100644
--- a/Source/Shaders/BillboardCollectionVS.glsl
+++ b/Source/Shaders/BillboardCollectionVS.glsl
@@ -9,10 +9,9 @@ attribute vec4 compressedAttribute2;                       // image height, colo
 attribute vec4 eyeOffset;                                  // eye offset in meters, 4 bytes free (texture range)
 attribute vec4 scaleByDistance;                            // near, nearScale, far, farScale
 attribute vec4 pixelOffsetScaleByDistance;                 // near, nearScale, far, farScale
-attribute vec3 distanceDisplayConditionAndDisableDepth;    // near, far, disableDepthTestDistance
+attribute vec4 compressedAttribute3;                       // distnace display condition near, far, disableDepthTestDistance, dimensions
 #ifdef CLAMP_TO_GROUND
-attribute vec4 textureCoordinateBounds;                              // the min and max x and y values for the texture coordinates
-attribute vec2 dimensions;
+attribute vec4 textureCoordinateBounds;                    // the min and max x and y values for the texture coordinates
 #endif
 #ifdef VECTOR_TILE
 attribute float a_batchId;
@@ -21,14 +20,10 @@ attribute float a_batchId;
 varying vec2 v_textureCoordinates;
 #ifdef CLAMP_TO_GROUND
 varying vec4 v_textureCoordinateBounds;
-varying vec2 v_originTextureCoordinate;
-varying vec2 v_leftTextureCoordinate;
-varying vec2 v_rightTextureCoordinate;
-varying vec2 v_dimensions;
-varying vec2 v_imageSize;
-varying vec2 v_translate;
-varying float v_eyeDepth;
-varying float v_disableDepthTestDistance;
+varying vec4 v_originTextureCoordinateAndTranslate;
+varying vec4 v_leftAndRightTextureCoordinate;
+varying vec4 v_dimensionsAndImageSize;
+varying vec2 v_eyeDepthAndDistance;
 #endif
 
 varying vec4 v_pickColor;
@@ -37,6 +32,7 @@ varying vec4 v_color;
 const float UPPER_BOUND = 32768.0;
 
 const float SHIFT_LEFT16 = 65536.0;
+const float SHIFT_LEFT12 = 4096.0;
 const float SHIFT_LEFT8 = 256.0;
 const float SHIFT_LEFT7 = 128.0;
 const float SHIFT_LEFT5 = 32.0;
@@ -44,6 +40,7 @@ const float SHIFT_LEFT3 = 8.0;
 const float SHIFT_LEFT2 = 4.0;
 const float SHIFT_LEFT1 = 2.0;
 
+const float SHIFT_RIGHT12 = 1.0 / 4096.0;
 const float SHIFT_RIGHT8 = 1.0 / 256.0;
 const float SHIFT_RIGHT7 = 1.0 / 128.0;
 const float SHIFT_RIGHT5 = 1.0 / 32.0;
@@ -163,7 +160,7 @@ void main()
     translate.y += (temp - floor(temp)) * SHIFT_LEFT8;
     translate.y -= UPPER_BOUND;
 
-    v_translate = translate.xy;
+    v_originTextureCoordinateAndTranslate.zw = translate.xy;
 
     temp = compressedAttribute1.x * SHIFT_RIGHT8;
 
@@ -171,24 +168,26 @@ void main()
 
 #ifdef CLAMP_TO_GROUND
     v_textureCoordinateBounds = textureCoordinateBounds;
-    v_originTextureCoordinate = vec2(1.0) - depthOrigin; //the origin
-    if (v_originTextureCoordinate.y == 1.0) //vertical origin is top
+    v_originTextureCoordinateAndTranslate.xy = vec2(1.0) - depthOrigin; //the origin
+    if (v_originTextureCoordinateAndTranslate.y == 1.0) //vertical origin is top
     {
-        v_leftTextureCoordinate = vec2(0.0); //bottom left
-        v_rightTextureCoordinate = vec2(1.0, 0.0); //bottom right
+        v_leftAndRightTextureCoordinate = vec4(0.0, 0.0, 1.0, 0.0); //bottom left, bottom right
     }
     else
     {
-        if (v_originTextureCoordinate.y == 0.0)
+        if (v_originTextureCoordinateAndTranslate.y == 0.0)
         {
-            v_originTextureCoordinate.y = 0.1;
+            v_originTextureCoordinateAndTranslate.y = 0.1;
         }
 
-        v_leftTextureCoordinate = vec2(0.0, 1.0); //top left
-        v_rightTextureCoordinate = vec2(1.0); //top right
+        v_leftAndRightTextureCoordinate = vec4(0.0, 1.0, 1.0, 1.0); //top left, top right
     }
-    v_dimensions = dimensions.xy;
-    v_imageSize = imageSize.xy;
+
+    temp = compressedAttribute3.w;
+    temp = temp * SHIFT_RIGHT12;
+    v_dimensionsAndImageSize.y = (temp - floor(temp)) * SHIFT_LEFT12;
+    v_dimensionsAndImageSize.x = floor(temp);
+    v_dimensionsAndImageSize.zw = imageSize.xy;
 #endif
 
 #ifdef EYE_DISTANCE_TRANSLUCENCY
@@ -244,7 +243,7 @@ void main()
     vec4 positionEC = czm_modelViewRelativeToEye * p;
 
 #ifdef CLAMP_TO_GROUND
-    v_eyeDepth = positionEC.z;
+    v_eyeDepthAndDistance.x = positionEC.z;
 #endif
 
     positionEC = czm_eyeOffset(positionEC, eyeOffset.xyz);
@@ -293,8 +292,8 @@ void main()
 #endif
 
 #ifdef DISTANCE_DISPLAY_CONDITION
-    float nearSq = distanceDisplayConditionAndDisableDepth.x;
-    float farSq = distanceDisplayConditionAndDisableDepth.y;
+    float nearSq = compressedAttribute3.x;
+    float farSq = compressedAttribute3.y;
     if (lengthSq < nearSq || lengthSq > farSq)
     {
         positionEC.xyz = vec3(0.0);
@@ -310,10 +309,10 @@ void main()
 #endif
 
 #ifdef DISABLE_DEPTH_DISTANCE
-    float disableDepthTestDistance = distanceDisplayConditionAndDisableDepth.z;
+    float disableDepthTestDistance = compressedAttribute3.z;
 
     #ifdef CLAMP_TO_GROUND
-    v_disableDepthTestDistance = disableDepthTestDistance;
+    v_eyeDepthAndDistance.y = disableDepthTestDistance;
     #endif
 
     if (disableDepthTestDistance == 0.0 && czm_minimumDisableDepthTestDistance != 0.0)

From 072c0c80ead81f4cd5b7153822974f7f73cd4b80 Mon Sep 17 00:00:00 2001
From: hpinkos <pinkos.hannah@gmail.com>
Date: Wed, 13 Jun 2018 10:21:14 -0400
Subject: [PATCH 04/12] CHANGES.md

---
 CHANGES.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGES.md b/CHANGES.md
index 433cae97418b..2a2e2f79a4e4 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -14,6 +14,7 @@ Change Log
 ##### Fixes :wrench:
 * Fixed a bug causing crashes with custom vertex attributes on `Geometry` crossing the IDL. Attributes will be barycentrically interpolated. [#6644](https://github.com/AnalyticalGraphicsInc/cesium/pull/6644)
 * Fixed a bug with Draco encoded i3dm tiles, and loading two Draco models with the same url. [#6668](https://github.com/AnalyticalGraphicsInc/cesium/issues/6668)
+* Improved billboard and label rendering so they no longer sink into terrain when clamped to ground. [#6621](https://github.com/AnalyticalGraphicsInc/cesium/pull/6621)
 
 ### 1.46.1 - 2018-06-01
 

From 493b8ce27e850331bb73900436da90ad3dd3623e Mon Sep 17 00:00:00 2001
From: hpinkos <pinkos.hannah@gmail.com>
Date: Mon, 18 Jun 2018 16:40:24 -0400
Subject: [PATCH 05/12] cleanup

---
 Source/Shaders/BillboardCollectionFS.glsl |  5 ++---
 Source/Shaders/BillboardCollectionVS.glsl | 19 ++-----------------
 2 files changed, 4 insertions(+), 20 deletions(-)

diff --git a/Source/Shaders/BillboardCollectionFS.glsl b/Source/Shaders/BillboardCollectionFS.glsl
index 2aa8c03e6e50..0e5e99dd8618 100644
--- a/Source/Shaders/BillboardCollectionFS.glsl
+++ b/Source/Shaders/BillboardCollectionFS.glsl
@@ -11,7 +11,6 @@ varying vec4 v_color;
 #ifdef CLAMP_TO_GROUND
 varying vec4 v_textureCoordinateBounds;                  // the min and max x and y values for the texture coordinates
 varying vec4 v_originTextureCoordinateAndTranslate;      // texture coordinate at the origin, billboard translate (used for label glyphs)
-varying vec4 v_leftAndRightTextureCoordinate;            // texture coordinates for left and right depth test
 varying vec4 v_dimensionsAndImageSize;                   // dimensions of the bounding rectangle and the size of the image.  The values will only be different for label glyphs
 varying vec2 v_eyeDepthAndDistance;                      // The depth of the billboard and the disable depth test distance
 
@@ -88,10 +87,10 @@ void main()
         // negative values go into the screen
         if (globeDepth1 != 0.0 && globeDepth1 > epsilonEyeDepth)
         {
-            float globeDepth2 = getGlobeDepth(adjustedST, v_leftAndRightTextureCoordinate.xy);
+            float globeDepth2 = getGlobeDepth(adjustedST, vec2(0.0, 1.0)); // top left corner
             if (globeDepth2 != 0.0 && globeDepth2 > epsilonEyeDepth)
             {
-                float globeDepth3 = getGlobeDepth(adjustedST, v_leftAndRightTextureCoordinate.zw);
+                float globeDepth3 = getGlobeDepth(adjustedST, vec2(1.0, 1.0)); // top right corner
                 if (globeDepth3 != 0.0 && globeDepth3 > epsilonEyeDepth)
                 {
                     discard;
diff --git a/Source/Shaders/BillboardCollectionVS.glsl b/Source/Shaders/BillboardCollectionVS.glsl
index dd5f7c60a19c..e046ac8b9c31 100644
--- a/Source/Shaders/BillboardCollectionVS.glsl
+++ b/Source/Shaders/BillboardCollectionVS.glsl
@@ -21,7 +21,6 @@ varying vec2 v_textureCoordinates;
 #ifdef CLAMP_TO_GROUND
 varying vec4 v_textureCoordinateBounds;
 varying vec4 v_originTextureCoordinateAndTranslate;
-varying vec4 v_leftAndRightTextureCoordinate;
 varying vec4 v_dimensionsAndImageSize;
 varying vec2 v_eyeDepthAndDistance;
 #endif
@@ -160,28 +159,14 @@ void main()
     translate.y += (temp - floor(temp)) * SHIFT_LEFT8;
     translate.y -= UPPER_BOUND;
 
-    v_originTextureCoordinateAndTranslate.zw = translate.xy;
-
     temp = compressedAttribute1.x * SHIFT_RIGHT8;
 
     vec2 imageSize = vec2(floor(temp), compressedAttribute2.w);
 
 #ifdef CLAMP_TO_GROUND
-    v_textureCoordinateBounds = textureCoordinateBounds;
     v_originTextureCoordinateAndTranslate.xy = vec2(1.0) - depthOrigin; //the origin
-    if (v_originTextureCoordinateAndTranslate.y == 1.0) //vertical origin is top
-    {
-        v_leftAndRightTextureCoordinate = vec4(0.0, 0.0, 1.0, 0.0); //bottom left, bottom right
-    }
-    else
-    {
-        if (v_originTextureCoordinateAndTranslate.y == 0.0)
-        {
-            v_originTextureCoordinateAndTranslate.y = 0.1;
-        }
-
-        v_leftAndRightTextureCoordinate = vec4(0.0, 1.0, 1.0, 1.0); //top left, top right
-    }
+    v_originTextureCoordinateAndTranslate.zw = translate.xy;
+    v_textureCoordinateBounds = textureCoordinateBounds;
 
     temp = compressedAttribute3.w;
     temp = temp * SHIFT_RIGHT12;

From 64e0d3a60b3e10358e4bf899f4e69bf4dae123ce Mon Sep 17 00:00:00 2001
From: hpinkos <pinkos.hannah@gmail.com>
Date: Mon, 18 Jun 2018 16:58:09 -0400
Subject: [PATCH 06/12] adjust epsilon

---
 Source/Shaders/BillboardCollectionFS.glsl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Source/Shaders/BillboardCollectionFS.glsl b/Source/Shaders/BillboardCollectionFS.glsl
index 0e5e99dd8618..a055d4dd617e 100644
--- a/Source/Shaders/BillboardCollectionFS.glsl
+++ b/Source/Shaders/BillboardCollectionFS.glsl
@@ -81,7 +81,7 @@ void main()
         vec2 adjustedST = v_textureCoordinates - v_textureCoordinateBounds.xy;
         adjustedST = adjustedST / vec2(v_textureCoordinateBounds.z - v_textureCoordinateBounds.x, v_textureCoordinateBounds.w - v_textureCoordinateBounds.y);
 
-        float epsilonEyeDepth = v_eyeDepthAndDistance.x + czm_epsilon5;
+        float epsilonEyeDepth = v_eyeDepthAndDistance.x + czm_epsilon1;
         float globeDepth1 = getGlobeDepth(adjustedST, v_originTextureCoordinateAndTranslate.xy);
 
         // negative values go into the screen

From 6b0e54fb2a200d3ed7d00c5fd594ca119bcbabfc Mon Sep 17 00:00:00 2001
From: hpinkos <pinkos.hannah@gmail.com>
Date: Tue, 19 Jun 2018 14:56:46 -0400
Subject: [PATCH 07/12] fix label picks

---
 Source/Scene/Billboard.js                 |  1 +
 Source/Scene/BillboardCollection.js       | 13 ++++++----
 Source/Scene/LabelCollection.js           |  2 ++
 Source/Shaders/BillboardCollectionFS.glsl | 14 +++++-----
 Source/Shaders/BillboardCollectionVS.glsl | 31 +++++++++++++++++------
 5 files changed, 41 insertions(+), 20 deletions(-)

diff --git a/Source/Scene/Billboard.js b/Source/Scene/Billboard.js
index 52946cd882dc..0baeef037daf 100644
--- a/Source/Scene/Billboard.js
+++ b/Source/Scene/Billboard.js
@@ -160,6 +160,7 @@ define([
         this._imageHeight = undefined;
 
         this._labelDimensions = undefined;
+        this._labelHorizontalOrigin = undefined;
 
         var image = options.image;
         var imageId = options.imageId;
diff --git a/Source/Scene/BillboardCollection.js b/Source/Scene/BillboardCollection.js
index a0647289f835..9c8cf9f31104 100644
--- a/Source/Scene/BillboardCollection.js
+++ b/Source/Scene/BillboardCollection.js
@@ -1033,6 +1033,9 @@ define([
         var dimensions = billboardCollection._textureAtlas.texture.dimensions;
         var imageHeight = Math.round(defaultValue(billboard.height, dimensions.y * height));
         billboardCollection._maxSize = Math.max(billboardCollection._maxSize, imageHeight);
+        var labelHorizontalOrigin = defaultValue(billboard._labelHorizontalOrigin, -2);
+        labelHorizontalOrigin += 2;
+        var compressed3 = imageHeight * LEFT_SHIFT2 + labelHorizontalOrigin;
 
         var red = Color.floatToByte(color.red);
         var green = Color.floatToByte(color.green);
@@ -1049,13 +1052,13 @@ define([
 
         if (billboardCollection._instanced) {
             i = billboard._index;
-            writer(i, compressed0, compressed1, compressed2, imageHeight);
+            writer(i, compressed0, compressed1, compressed2, compressed3);
         } else {
             i = billboard._index * 4;
-            writer(i + 0, compressed0, compressed1, compressed2, imageHeight);
-            writer(i + 1, compressed0, compressed1, compressed2, imageHeight);
-            writer(i + 2, compressed0, compressed1, compressed2, imageHeight);
-            writer(i + 3, compressed0, compressed1, compressed2, imageHeight);
+            writer(i + 0, compressed0, compressed1, compressed2, compressed3);
+            writer(i + 1, compressed0, compressed1, compressed2, compressed3);
+            writer(i + 2, compressed0, compressed1, compressed2, compressed3);
+            writer(i + 3, compressed0, compressed1, compressed2, compressed3);
         }
     }
 
diff --git a/Source/Scene/LabelCollection.js b/Source/Scene/LabelCollection.js
index 049810abdf32..e6ac85dab71a 100644
--- a/Source/Scene/LabelCollection.js
+++ b/Source/Scene/LabelCollection.js
@@ -347,6 +347,7 @@ define([
         if (defined(backgroundBillboard)) {
             totalLineWidth += (backgroundPadding.x * 2);
             totalLineHeight += (backgroundPadding.y * 2);
+            backgroundBillboard._labelHorizontalOrigin = horizontalOrigin;
         }
 
         glyphPixelOffset.x = widthOffset * scale * resolutionScale;
@@ -380,6 +381,7 @@ define([
                     glyph.billboard._setTranslate(glyphPixelOffset);
                     glyph.billboard._labelDimensions.x = totalLineWidth;
                     glyph.billboard._labelDimensions.y = totalLineHeight;
+                    glyph.billboard._labelHorizontalOrigin = horizontalOrigin;
                 }
 
                 //Compute the next x offset taking into acocunt the kerning performed
diff --git a/Source/Shaders/BillboardCollectionFS.glsl b/Source/Shaders/BillboardCollectionFS.glsl
index a055d4dd617e..6f3734cd38ee 100644
--- a/Source/Shaders/BillboardCollectionFS.glsl
+++ b/Source/Shaders/BillboardCollectionFS.glsl
@@ -12,7 +12,7 @@ varying vec4 v_color;
 varying vec4 v_textureCoordinateBounds;                  // the min and max x and y values for the texture coordinates
 varying vec4 v_originTextureCoordinateAndTranslate;      // texture coordinate at the origin, billboard translate (used for label glyphs)
 varying vec4 v_dimensionsAndImageSize;                   // dimensions of the bounding rectangle and the size of the image.  The values will only be different for label glyphs
-varying vec2 v_eyeDepthAndDistance;                      // The depth of the billboard and the disable depth test distance
+varying vec3 v_eyeDepthDistanceAndApplyTranslate;        // The depth of the billboard and the disable depth test distance
 
 float getGlobeDepth(vec2 adjustedST, vec2 depthLookupST)
 {
@@ -20,17 +20,17 @@ float getGlobeDepth(vec2 adjustedST, vec2 depthLookupST)
     vec2 imageSize = v_dimensionsAndImageSize.zw;
 
     vec2 lookupVector = imageSize * (depthLookupST - adjustedST);
-    vec2 labelOffset = depthLookupST * (dimensions - imageSize); // aligns label glyph with bounding rectangle.  Will be zero for billboards because dimensions and imageSize will be equal
+    vec2 labelOffset = depthLookupST * (dimensions - imageSize) * vec2(1.0, 1.0 - v_originTextureCoordinateAndTranslate.y); // aligns label glyph with bounding rectangle.  Will be zero for billboards because dimensions and imageSize will be equal
     vec2 translation = v_originTextureCoordinateAndTranslate.zw;
-    if (translation != vec2(0.0))
+
+    if (v_eyeDepthDistanceAndApplyTranslate.z != 0.0)
     {
         // this is only needed for labels where the horizontal origin is not LEFT
         // it moves the label back to where the "origin" should be since all label glyphs are set to HorizontalOrigin.LEFT
-        translation += (dimensions * v_originTextureCoordinateAndTranslate.xy * vec2(0, -1));
+        translation += (dimensions * v_originTextureCoordinateAndTranslate.xy * vec2(1.0, 0.0));
     }
 
     vec2 st = ((lookupVector - translation + labelOffset) + gl_FragCoord.xy) / czm_viewport.zw;
-
     float logDepthOrDepth = czm_unpackDepth(texture2D(czm_globeDepthTexture, st));
 
     if (logDepthOrDepth == 0.0)
@@ -77,11 +77,11 @@ void main()
     czm_writeLogDepth();
 
 #ifdef CLAMP_TO_GROUND
-    if (v_eyeDepthAndDistance.x > -v_eyeDepthAndDistance.y) {
+    if (v_eyeDepthDistanceAndApplyTranslate.x > -v_eyeDepthDistanceAndApplyTranslate.y) {
         vec2 adjustedST = v_textureCoordinates - v_textureCoordinateBounds.xy;
         adjustedST = adjustedST / vec2(v_textureCoordinateBounds.z - v_textureCoordinateBounds.x, v_textureCoordinateBounds.w - v_textureCoordinateBounds.y);
 
-        float epsilonEyeDepth = v_eyeDepthAndDistance.x + czm_epsilon1;
+        float epsilonEyeDepth = v_eyeDepthDistanceAndApplyTranslate.x + czm_epsilon1;
         float globeDepth1 = getGlobeDepth(adjustedST, v_originTextureCoordinateAndTranslate.xy);
 
         // negative values go into the screen
diff --git a/Source/Shaders/BillboardCollectionVS.glsl b/Source/Shaders/BillboardCollectionVS.glsl
index e046ac8b9c31..5b74712c4e58 100644
--- a/Source/Shaders/BillboardCollectionVS.glsl
+++ b/Source/Shaders/BillboardCollectionVS.glsl
@@ -5,11 +5,11 @@ attribute vec4 positionHighAndScale;
 attribute vec4 positionLowAndRotation;
 attribute vec4 compressedAttribute0;                       // pixel offset, translate, horizontal origin, vertical origin, show, direction, texture coordinates (texture offset)
 attribute vec4 compressedAttribute1;                       // aligned axis, translucency by distance, image width
-attribute vec4 compressedAttribute2;                       // image height, color, pick color, size in meters, valid aligned axis, 13 bits free
+attribute vec4 compressedAttribute2;                       // label horizontal origin, image height, color, pick color, size in meters, valid aligned axis, 13 bits free
 attribute vec4 eyeOffset;                                  // eye offset in meters, 4 bytes free (texture range)
 attribute vec4 scaleByDistance;                            // near, nearScale, far, farScale
 attribute vec4 pixelOffsetScaleByDistance;                 // near, nearScale, far, farScale
-attribute vec4 compressedAttribute3;                       // distnace display condition near, far, disableDepthTestDistance, dimensions
+attribute vec4 compressedAttribute3;                       // distance display condition near, far, disableDepthTestDistance, dimensions
 #ifdef CLAMP_TO_GROUND
 attribute vec4 textureCoordinateBounds;                    // the min and max x and y values for the texture coordinates
 #endif
@@ -22,7 +22,7 @@ varying vec2 v_textureCoordinates;
 varying vec4 v_textureCoordinateBounds;
 varying vec4 v_originTextureCoordinateAndTranslate;
 varying vec4 v_dimensionsAndImageSize;
-varying vec2 v_eyeDepthAndDistance;
+varying vec3 v_eyeDepthDistanceAndApplyTranslate;
 #endif
 
 varying vec4 v_pickColor;
@@ -128,7 +128,7 @@ void main()
     compressed -= origin.y * SHIFT_LEFT3;
 
 #ifdef CLAMP_TO_GROUND
-    vec2 depthOrigin = origin.xy * 0.5;
+    vec2 depthOrigin = origin.xy;
 #endif
     origin -= vec2(1.0);
 
@@ -160,11 +160,25 @@ void main()
     translate.y -= UPPER_BOUND;
 
     temp = compressedAttribute1.x * SHIFT_RIGHT8;
+    float temp2 = floor(compressedAttribute2.w * SHIFT_RIGHT2);
 
-    vec2 imageSize = vec2(floor(temp), compressedAttribute2.w);
+    vec2 imageSize = vec2(floor(temp), temp2);
 
 #ifdef CLAMP_TO_GROUND
-    v_originTextureCoordinateAndTranslate.xy = vec2(1.0) - depthOrigin; //the origin
+    float labelHorizontalOrigin = floor(compressedAttribute2.w - (temp2 * SHIFT_LEFT2));
+
+    if (labelHorizontalOrigin == 0.0) // is a billboard, so set apply translate to false
+    {
+        v_eyeDepthDistanceAndApplyTranslate.z = 0.0;
+    }
+    else // is a label, so we need to grab the correct horizontal origin texture coordinate
+    {
+        labelHorizontalOrigin -= 2.0;
+        v_eyeDepthDistanceAndApplyTranslate.z = 1.0;
+        depthOrigin.x = labelHorizontalOrigin + 1.0;
+    }
+
+    v_originTextureCoordinateAndTranslate.xy = vec2(1.0) - (depthOrigin * 0.5);
     v_originTextureCoordinateAndTranslate.zw = translate.xy;
     v_textureCoordinateBounds = textureCoordinateBounds;
 
@@ -172,6 +186,7 @@ void main()
     temp = temp * SHIFT_RIGHT12;
     v_dimensionsAndImageSize.y = (temp - floor(temp)) * SHIFT_LEFT12;
     v_dimensionsAndImageSize.x = floor(temp);
+
     v_dimensionsAndImageSize.zw = imageSize.xy;
 #endif
 
@@ -228,7 +243,7 @@ void main()
     vec4 positionEC = czm_modelViewRelativeToEye * p;
 
 #ifdef CLAMP_TO_GROUND
-    v_eyeDepthAndDistance.x = positionEC.z;
+    v_eyeDepthDistanceAndApplyTranslate.x = positionEC.z;
 #endif
 
     positionEC = czm_eyeOffset(positionEC, eyeOffset.xyz);
@@ -297,7 +312,7 @@ void main()
     float disableDepthTestDistance = compressedAttribute3.z;
 
     #ifdef CLAMP_TO_GROUND
-    v_eyeDepthAndDistance.y = disableDepthTestDistance;
+    v_eyeDepthDistanceAndApplyTranslate.y = disableDepthTestDistance;
     #endif
 
     if (disableDepthTestDistance == 0.0 && czm_minimumDisableDepthTestDistance != 0.0)

From be0000c128369b72d18126fd8f2dba0ea9f99dbe Mon Sep 17 00:00:00 2001
From: hpinkos <pinkos.hannah@gmail.com>
Date: Tue, 19 Jun 2018 16:54:26 -0400
Subject: [PATCH 08/12] fix ie

---
 Source/Scene/BillboardCollection.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Source/Scene/BillboardCollection.js b/Source/Scene/BillboardCollection.js
index 9c8cf9f31104..89bcb04985c7 100644
--- a/Source/Scene/BillboardCollection.js
+++ b/Source/Scene/BillboardCollection.js
@@ -1192,7 +1192,7 @@ define([
         }
 
         var disableDepthTestDistance = billboard.disableDepthTestDistance;
-        if (billboard.heightReference === HeightReference.CLAMP_TO_GROUND && disableDepthTestDistance === 0.0) {
+        if (billboard.heightReference === HeightReference.CLAMP_TO_GROUND && disableDepthTestDistance === 0.0 && billboardCollection._scene.context.depthTexture) {
             disableDepthTestDistance = 2000.0;
         }
 
@@ -1251,7 +1251,7 @@ define([
 
     function writeTextureCoordinateBounds(billboardCollection, context, textureAtlasCoordinates, vafWriters, billboard) {
         if (billboard.heightReference === HeightReference.CLAMP_TO_GROUND) {
-            billboardCollection._shaderClampToGround = true;
+            billboardCollection._shaderClampToGround = billboardCollection._scene.context.depthTexture;
         }
         var i;
         var writer = vafWriters[attributeLocations.textureCoordinateBounds];

From 5883a2b8920f14f2f82dcd4462eea4243c80f77a Mon Sep 17 00:00:00 2001
From: hpinkos <pinkos.hannah@gmail.com>
Date: Tue, 19 Jun 2018 18:06:24 -0400
Subject: [PATCH 09/12] fix scale

---
 Source/Shaders/BillboardCollectionVS.glsl | 39 +++++++++++------------
 1 file changed, 19 insertions(+), 20 deletions(-)

diff --git a/Source/Shaders/BillboardCollectionVS.glsl b/Source/Shaders/BillboardCollectionVS.glsl
index 5b74712c4e58..9355caf93108 100644
--- a/Source/Shaders/BillboardCollectionVS.glsl
+++ b/Source/Shaders/BillboardCollectionVS.glsl
@@ -166,28 +166,21 @@ void main()
 
 #ifdef CLAMP_TO_GROUND
     float labelHorizontalOrigin = floor(compressedAttribute2.w - (temp2 * SHIFT_LEFT2));
-
-    if (labelHorizontalOrigin == 0.0) // is a billboard, so set apply translate to false
-    {
-        v_eyeDepthDistanceAndApplyTranslate.z = 0.0;
-    }
-    else // is a label, so we need to grab the correct horizontal origin texture coordinate
+    float applyTranslate = 0.0;
+    if (labelHorizontalOrigin != 0.0) // is a billboard, so set apply translate to false
     {
+        applyTranslate = 1.0;
         labelHorizontalOrigin -= 2.0;
-        v_eyeDepthDistanceAndApplyTranslate.z = 1.0;
         depthOrigin.x = labelHorizontalOrigin + 1.0;
     }
 
-    v_originTextureCoordinateAndTranslate.xy = vec2(1.0) - (depthOrigin * 0.5);
-    v_originTextureCoordinateAndTranslate.zw = translate.xy;
-    v_textureCoordinateBounds = textureCoordinateBounds;
+    depthOrigin = vec2(1.0) - (depthOrigin * 0.5);
 
     temp = compressedAttribute3.w;
     temp = temp * SHIFT_RIGHT12;
-    v_dimensionsAndImageSize.y = (temp - floor(temp)) * SHIFT_LEFT12;
-    v_dimensionsAndImageSize.x = floor(temp);
-
-    v_dimensionsAndImageSize.zw = imageSize.xy;
+    vec2 dimensions;
+    dimensions.y = (temp - floor(temp)) * SHIFT_LEFT12;
+    dimensions.x = floor(temp);
 #endif
 
 #ifdef EYE_DISTANCE_TRANSLUCENCY
@@ -243,7 +236,7 @@ void main()
     vec4 positionEC = czm_modelViewRelativeToEye * p;
 
 #ifdef CLAMP_TO_GROUND
-    v_eyeDepthDistanceAndApplyTranslate.x = positionEC.z;
+    float eyeDepth = positionEC.z;
 #endif
 
     positionEC = czm_eyeOffset(positionEC, eyeOffset.xyz);
@@ -311,10 +304,6 @@ void main()
 #ifdef DISABLE_DEPTH_DISTANCE
     float disableDepthTestDistance = compressedAttribute3.z;
 
-    #ifdef CLAMP_TO_GROUND
-    v_eyeDepthDistanceAndApplyTranslate.y = disableDepthTestDistance;
-    #endif
-
     if (disableDepthTestDistance == 0.0 && czm_minimumDisableDepthTestDistance != 0.0)
     {
         disableDepthTestDistance = czm_minimumDisableDepthTestDistance;
@@ -336,9 +325,19 @@ void main()
     }
 #endif
 
+#ifdef CLAMP_TO_GROUND
+    v_eyeDepthDistanceAndApplyTranslate.x = eyeDepth;
+    v_eyeDepthDistanceAndApplyTranslate.y = disableDepthTestDistance;
+    v_eyeDepthDistanceAndApplyTranslate.z = applyTranslate;
+    v_originTextureCoordinateAndTranslate.xy = depthOrigin;
+    v_originTextureCoordinateAndTranslate.zw = translate;
+    v_textureCoordinateBounds = textureCoordinateBounds;
+    v_dimensionsAndImageSize.xy = dimensions * scale;
+    v_dimensionsAndImageSize.zw = imageSize * scale;
+#endif
+
     v_pickColor = pickColor;
 
     v_color = color;
     v_color.a *= translucency;
-
 }

From 8d905c6a8d8f05858e2bcb031d596902fcaf52fc Mon Sep 17 00:00:00 2001
From: hpinkos <pinkos.hannah@gmail.com>
Date: Wed, 20 Jun 2018 13:55:21 -0400
Subject: [PATCH 10/12] fix rotation

---
 Source/Shaders/BillboardCollectionFS.glsl | 2 ++
 Source/Shaders/BillboardCollectionVS.glsl | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/Source/Shaders/BillboardCollectionFS.glsl b/Source/Shaders/BillboardCollectionFS.glsl
index 6f3734cd38ee..495c484f6d0c 100644
--- a/Source/Shaders/BillboardCollectionFS.glsl
+++ b/Source/Shaders/BillboardCollectionFS.glsl
@@ -13,6 +13,7 @@ varying vec4 v_textureCoordinateBounds;                  // the min and max x an
 varying vec4 v_originTextureCoordinateAndTranslate;      // texture coordinate at the origin, billboard translate (used for label glyphs)
 varying vec4 v_dimensionsAndImageSize;                   // dimensions of the bounding rectangle and the size of the image.  The values will only be different for label glyphs
 varying vec3 v_eyeDepthDistanceAndApplyTranslate;        // The depth of the billboard and the disable depth test distance
+varying mat2 v_rotationMatrix;
 
 float getGlobeDepth(vec2 adjustedST, vec2 depthLookupST)
 {
@@ -20,6 +21,7 @@ float getGlobeDepth(vec2 adjustedST, vec2 depthLookupST)
     vec2 imageSize = v_dimensionsAndImageSize.zw;
 
     vec2 lookupVector = imageSize * (depthLookupST - adjustedST);
+    lookupVector = v_rotationMatrix * lookupVector;
     vec2 labelOffset = depthLookupST * (dimensions - imageSize) * vec2(1.0, 1.0 - v_originTextureCoordinateAndTranslate.y); // aligns label glyph with bounding rectangle.  Will be zero for billboards because dimensions and imageSize will be equal
     vec2 translation = v_originTextureCoordinateAndTranslate.zw;
 
diff --git a/Source/Shaders/BillboardCollectionVS.glsl b/Source/Shaders/BillboardCollectionVS.glsl
index 9355caf93108..7ed335d58e03 100644
--- a/Source/Shaders/BillboardCollectionVS.glsl
+++ b/Source/Shaders/BillboardCollectionVS.glsl
@@ -23,6 +23,7 @@ varying vec4 v_textureCoordinateBounds;
 varying vec4 v_originTextureCoordinateAndTranslate;
 varying vec4 v_dimensionsAndImageSize;
 varying vec3 v_eyeDepthDistanceAndApplyTranslate;
+varying mat2 v_rotationMatrix;
 #endif
 
 varying vec4 v_pickColor;
@@ -71,6 +72,10 @@ vec4 addScreenSpaceOffset(vec4 positionEC, vec2 imageSize, float scale, vec2 dir
         float sinTheta = sin(angle);
         mat2 rotationMatrix = mat2(cosTheta, sinTheta, -sinTheta, cosTheta);
         halfSize = rotationMatrix * halfSize;
+
+        #ifdef CLAMP_TO_GROUND
+            v_rotationMatrix = rotationMatrix;
+        #endif
     }
 #endif
 
@@ -237,6 +242,7 @@ void main()
 
 #ifdef CLAMP_TO_GROUND
     float eyeDepth = positionEC.z;
+    v_rotationMatrix = mat2(1.0, 0.0, 0.0, 1.0);
 #endif
 
     positionEC = czm_eyeOffset(positionEC, eyeOffset.xyz);

From 9493e4d41fe8e24b9864a369b8f4b7b4f2aadeac Mon Sep 17 00:00:00 2001
From: hpinkos <pinkos.hannah@gmail.com>
Date: Wed, 20 Jun 2018 18:08:05 -0400
Subject: [PATCH 11/12] math

---
 Source/Shaders/BillboardCollectionFS.glsl | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Source/Shaders/BillboardCollectionFS.glsl b/Source/Shaders/BillboardCollectionFS.glsl
index 495c484f6d0c..e306c2735cf5 100644
--- a/Source/Shaders/BillboardCollectionFS.glsl
+++ b/Source/Shaders/BillboardCollectionFS.glsl
@@ -22,7 +22,8 @@ float getGlobeDepth(vec2 adjustedST, vec2 depthLookupST)
 
     vec2 lookupVector = imageSize * (depthLookupST - adjustedST);
     lookupVector = v_rotationMatrix * lookupVector;
-    vec2 labelOffset = depthLookupST * (dimensions - imageSize) * vec2(1.0, 1.0 - v_originTextureCoordinateAndTranslate.y); // aligns label glyph with bounding rectangle.  Will be zero for billboards because dimensions and imageSize will be equal
+    vec2 labelOffset = (dimensions - imageSize) * (depthLookupST - vec2(0.0, v_originTextureCoordinateAndTranslate.y)); // aligns label glyph with bounding rectangle.  Will be zero for billboards because dimensions and imageSize will be equal
+
     vec2 translation = v_originTextureCoordinateAndTranslate.zw;
 
     if (v_eyeDepthDistanceAndApplyTranslate.z != 0.0)

From 4c3da3b2dbeb023d20279e1b24a962f32d450ebd Mon Sep 17 00:00:00 2001
From: hpinkos <pinkos.hannah@gmail.com>
Date: Thu, 21 Jun 2018 14:40:08 -0400
Subject: [PATCH 12/12] size in meters

---
 Source/Shaders/BillboardCollectionVS.glsl | 110 +++++++++++-----------
 1 file changed, 54 insertions(+), 56 deletions(-)

diff --git a/Source/Shaders/BillboardCollectionVS.glsl b/Source/Shaders/BillboardCollectionVS.glsl
index 7ed335d58e03..857d7368b59f 100644
--- a/Source/Shaders/BillboardCollectionVS.glsl
+++ b/Source/Shaders/BillboardCollectionVS.glsl
@@ -48,61 +48,6 @@ const float SHIFT_RIGHT3 = 1.0 / 8.0;
 const float SHIFT_RIGHT2 = 1.0 / 4.0;
 const float SHIFT_RIGHT1 = 1.0 / 2.0;
 
-vec4 addScreenSpaceOffset(vec4 positionEC, vec2 imageSize, float scale, vec2 direction, vec2 origin, vec2 translate, vec2 pixelOffset, vec3 alignedAxis, bool validAlignedAxis, float rotation, bool sizeInMeters)
-{
-    // Note the halfSize cannot be computed in JavaScript because it is sent via
-    // compressed vertex attributes that coerce it to an integer.
-    vec2 halfSize = imageSize * scale * czm_resolutionScale * 0.5;
-    halfSize *= ((direction * 2.0) - 1.0);
-
-    vec2 originTranslate = origin * abs(halfSize);
-
-#if defined(ROTATION) || defined(ALIGNED_AXIS)
-    if (validAlignedAxis || rotation != 0.0)
-    {
-        float angle = rotation;
-        if (validAlignedAxis)
-        {
-            vec4 projectedAlignedAxis = czm_modelViewProjection * vec4(alignedAxis, 0.0);
-            angle += sign(-projectedAlignedAxis.x) * acos( sign(projectedAlignedAxis.y) * (projectedAlignedAxis.y * projectedAlignedAxis.y) /
-                    (projectedAlignedAxis.x * projectedAlignedAxis.x + projectedAlignedAxis.y * projectedAlignedAxis.y) );
-        }
-
-        float cosTheta = cos(angle);
-        float sinTheta = sin(angle);
-        mat2 rotationMatrix = mat2(cosTheta, sinTheta, -sinTheta, cosTheta);
-        halfSize = rotationMatrix * halfSize;
-
-        #ifdef CLAMP_TO_GROUND
-            v_rotationMatrix = rotationMatrix;
-        #endif
-    }
-#endif
-
-    if (sizeInMeters)
-    {
-        positionEC.xy += halfSize;
-    }
-
-    float mpp = czm_metersPerPixel(positionEC);
-
-    if (!sizeInMeters)
-    {
-        originTranslate *= mpp;
-    }
-
-    positionEC.xy += originTranslate;
-    if (!sizeInMeters)
-    {
-        positionEC.xy += halfSize * mpp;
-    }
-
-    positionEC.xy += translate * mpp;
-    positionEC.xy += (pixelOffset * czm_resolutionScale) * mpp;
-
-    return positionEC;
-}
-
 void main()
 {
     // Modifying this shader may also require modifications to Billboard._computeScreenSpacePosition
@@ -299,7 +244,55 @@ void main()
     }
 #endif
 
-    positionEC = addScreenSpaceOffset(positionEC, imageSize, scale, direction, origin, translate, pixelOffset, alignedAxis, validAlignedAxis, rotation, sizeInMeters);
+    // Note the halfSize cannot be computed in JavaScript because it is sent via
+    // compressed vertex attributes that coerce it to an integer.
+    vec2 halfSize = imageSize * scale * czm_resolutionScale * 0.5;
+    halfSize *= ((direction * 2.0) - 1.0);
+
+    vec2 originTranslate = origin * abs(halfSize);
+
+#if defined(ROTATION) || defined(ALIGNED_AXIS)
+    if (validAlignedAxis || rotation != 0.0)
+    {
+        float angle = rotation;
+        if (validAlignedAxis)
+        {
+            vec4 projectedAlignedAxis = czm_modelViewProjection * vec4(alignedAxis, 0.0);
+            angle += sign(-projectedAlignedAxis.x) * acos( sign(projectedAlignedAxis.y) * (projectedAlignedAxis.y * projectedAlignedAxis.y) /
+                    (projectedAlignedAxis.x * projectedAlignedAxis.x + projectedAlignedAxis.y * projectedAlignedAxis.y) );
+        }
+
+        float cosTheta = cos(angle);
+        float sinTheta = sin(angle);
+        mat2 rotationMatrix = mat2(cosTheta, sinTheta, -sinTheta, cosTheta);
+        halfSize = rotationMatrix * halfSize;
+
+        #ifdef CLAMP_TO_GROUND
+            v_rotationMatrix = rotationMatrix;
+        #endif
+    }
+#endif
+
+    if (sizeInMeters)
+    {
+        positionEC.xy += halfSize;
+    }
+
+    float mpp = czm_metersPerPixel(positionEC);
+
+    if (!sizeInMeters)
+    {
+        originTranslate *= mpp;
+    }
+
+    positionEC.xy += originTranslate;
+    if (!sizeInMeters)
+    {
+        positionEC.xy += halfSize * mpp;
+    }
+
+    positionEC.xy += translate * mpp;
+    positionEC.xy += (pixelOffset * czm_resolutionScale) * mpp;
     gl_Position = czm_projection * positionEC;
     v_textureCoordinates = textureCoordinates;
 
@@ -332,6 +325,11 @@ void main()
 #endif
 
 #ifdef CLAMP_TO_GROUND
+    if (sizeInMeters) {
+        translate /= mpp;
+        dimensions /= mpp;
+        imageSize /= mpp;
+    }
     v_eyeDepthDistanceAndApplyTranslate.x = eyeDepth;
     v_eyeDepthDistanceAndApplyTranslate.y = disableDepthTestDistance;
     v_eyeDepthDistanceAndApplyTranslate.z = applyTranslate;