Remove log depth skin workaround

CHANGES.md

@@ -9,6 +9,7 @@
 ##### Fixes :wrench:
 
 - Fixed error with `WallGeoemtry` when there were adjacent positions with very close values [#8952](https://github.com/CesiumGS/cesium/pull/8952)
+- Fixed artifact for skinned model when log depth is enabled. [#6447](https://github.com/CesiumGS/cesium/issues/6447)
 - Fixed a bug where certain rhumb arc polylines would lead to a crash. [#8787](https://github.com/CesiumGS/cesium/pull/8787)
 
 ### 1.70.1 - 2020-06-10

CONTRIBUTORS.md

@@ -264,3 +264,4 @@ See [CONTRIBUTING.md](CONTRIBUTING.md) for details on how to contribute to Cesiu
 - [Brandon Nguyen](https://github.com/bn-dignitas)
 - [Wang Bao](https://github.com/xiaobaogeit)
 - [John Remsberg](https://github.com/easternmotors)
+- [Bao Thien Tran](https://github.com/baothientran)

Source/Scene/ClassificationModel.js

@@ -647,9 +647,6 @@ function createProgram(model) {
   var drawVS = modifyShader(vs, model._vertexShaderLoaded);
   var drawFS = modifyShader(fs, model._classificationShaderLoaded);
 
-  drawVS = ModelUtility.modifyVertexShaderForLogDepth(drawVS, toClip);
-  drawFS = ModelUtility.modifyFragmentShaderForLogDepth(drawFS);
-
   model._shaderProgram = {
     vertexShaderSource: drawVS,
     fragmentShaderSource: drawFS,

Source/Scene/Model.js

@@ -2423,7 +2423,6 @@ function createProgram(programToCreate, model, context) {
   var fs = shaders[program.fragmentShader];
 
   var quantizedVertexShaders = model._quantizedVertexShaders;
-  var toClipCoordinatesGLSL = model._toClipCoordinatesGLSL[programId];
 
   if (
     model.extensionsUsed.WEB3D_quantized_attributes ||
@@ -2440,17 +2439,6 @@ function createProgram(programToCreate, model, context) {
   var drawVS = modifyShader(vs, programId, model._vertexShaderLoaded);
   var drawFS = modifyShader(fs, programId, model._fragmentShaderLoaded);
 
-  // Internet Explorer seems to have problems with discard (for clipping planes) after too many levels of indirection:
-  // https://github.com/CesiumGS/cesium/issues/6575.
-  // For IE log depth code is defined out anyway due to unsupported WebGL extensions, so the wrappers can be omitted.
-  if (!FeatureDetection.isInternetExplorer()) {
-    drawVS = ModelUtility.modifyVertexShaderForLogDepth(
-      drawVS,
-      toClipCoordinatesGLSL
-    );
-    drawFS = ModelUtility.modifyFragmentShaderForLogDepth(drawFS);
-  }
-
   if (!defined(model._uniformMapLoaded)) {
     drawFS = "uniform vec4 czm_pickColor;\n" + drawFS;
   }
@@ -2540,7 +2528,6 @@ function recreateProgram(programToCreate, model, context) {
   var shaders = model._rendererResources.sourceShaders;
 
   var quantizedVertexShaders = model._quantizedVertexShaders;
-  var toClipCoordinatesGLSL = model._toClipCoordinatesGLSL[programId];
 
   var clippingPlaneCollection = model.clippingPlanes;
   var addClippingPlaneCode = isClippingEnabled(model);
@@ -2570,14 +2557,6 @@ function recreateProgram(programToCreate, model, context) {
   var drawVS = modifyShader(vs, programId, model._vertexShaderLoaded);
   var drawFS = modifyShader(finalFS, programId, model._fragmentShaderLoaded);
 
-  if (!FeatureDetection.isInternetExplorer()) {
-    drawVS = ModelUtility.modifyVertexShaderForLogDepth(
-      drawVS,
-      toClipCoordinatesGLSL
-    );
-    drawFS = ModelUtility.modifyFragmentShaderForLogDepth(drawFS);
-  }
-
   if (!defined(model._uniformMapLoaded)) {
     drawFS = "uniform vec4 czm_pickColor;\n" + drawFS;
   }
@@ -4084,7 +4063,6 @@ function createResources(model, frameState) {
   var context = frameState.context;
   var scene3DOnly = frameState.scene3DOnly;
   var quantizedVertexShaders = model._quantizedVertexShaders;
-  var toClipCoordinates = (model._toClipCoordinatesGLSL = {});
   var techniques = model._sourceTechniques;
   var programs = model._sourcePrograms;
 
@@ -4120,10 +4098,6 @@ function createResources(model, frameState) {
       }
 
       shader = modifyShader(shader, programId, model._vertexShaderLoaded);
-      toClipCoordinates[programId] = ModelUtility.toClipCoordinatesGLSL(
-        model.gltf,
-        shader
-      );
     }
   }
 

Source/Scene/ModelUtility.js

@@ -903,85 +903,6 @@ ModelUtility.modifyShaderForQuantizedAttributes = function (
   };
 };
 
-ModelUtility.toClipCoordinatesGLSL = function (gltf, shader) {
-  var positionName = ModelUtility.getAttributeOrUniformBySemantic(
-    gltf,
-    "POSITION"
-  );
-  var decodedPositionName = positionName.replace("a_", "gltf_a_dec_");
-  if (shader.indexOf(decodedPositionName) !== -1) {
-    positionName = decodedPositionName;
-  }
-
-  var modelViewProjectionName = ModelUtility.getAttributeOrUniformBySemantic(
-    gltf,
-    "MODELVIEWPROJECTION",
-    undefined,
-    true
-  );
-  if (
-    !defined(modelViewProjectionName) ||
-    shader.indexOf(modelViewProjectionName) === -1
-  ) {
-    var projectionName = ModelUtility.getAttributeOrUniformBySemantic(
-      gltf,
-      "PROJECTION",
-      undefined,
-      true
-    );
-    var modelViewName = ModelUtility.getAttributeOrUniformBySemantic(
-      gltf,
-      "MODELVIEW",
-      undefined,
-      true
-    );
-    if (shader.indexOf("czm_instanced_modelView ") !== -1) {
-      modelViewName = "czm_instanced_modelView";
-    } else if (!defined(modelViewName)) {
-      modelViewName = ModelUtility.getAttributeOrUniformBySemantic(
-        gltf,
-        "CESIUM_RTC_MODELVIEW",
-        undefined,
-        true
-      );
-    }
-    modelViewProjectionName = projectionName + " * " + modelViewName;
-  }
-
-  return modelViewProjectionName + " * vec4(" + positionName + ".xyz, 1.0)";
-};
-
-ModelUtility.modifyFragmentShaderForLogDepth = function (shader) {
-  shader = ShaderSource.replaceMain(shader, "czm_depth_main");
-  shader +=
-    "\n" +
-    "void main() \n" +
-    "{ \n" +
-    "    czm_depth_main(); \n" +
-    "    czm_writeLogDepth(); \n" +
-    "} \n";
-
-  return shader;
-};
-
-ModelUtility.modifyVertexShaderForLogDepth = function (
-  shader,
-  toClipCoordinatesGLSL
-) {
-  shader = ShaderSource.replaceMain(shader, "czm_depth_main");
-  shader +=
-    "\n" +
-    "void main() \n" +
-    "{ \n" +
-    "    czm_depth_main(); \n" +
-    "    czm_vertexLogDepth(" +
-    toClipCoordinatesGLSL +
-    "); \n" +
-    "} \n";
-
-  return shader;
-};
-
 function getScalarUniformFunction(value) {
   var that = {
     value: value,

Specs/Scene/ModelSpec.js

@@ -2784,6 +2784,12 @@ describe(
 
     it("loads a glTF with KHR_materials_common that has skinning", function () {
       return loadModel(CesiumManUrl).then(function (m) {
+        // Face CesiumMan towards the camera. See https://github.com/CesiumGS/cesium/pull/8958#issuecomment-644352798
+        m.modelMatrix = Matrix4.multiply(
+          m.modelMatrix,
+          Axis.Y_UP_TO_X_UP,
+          new Matrix4()
+        );
         verifyRender(m);
         primitives.remove(m);
       });