Premultiplied alpha to fix colors for globe translucency

CesiumGS · Mar 4, 2021 · 0351120 · 0351120
1 parent e07921d
commit 0351120
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Showing 2 changed files with 4 additions and 1 deletion.
diff --git a/Source/Scene/Vector3DTileClampedPolylines.js b/Source/Scene/Vector3DTileClampedPolylines.js
@@ -478,7 +478,7 @@ function getRenderState(mask3DTiles) {
     cull: {
       enabled: true, // prevent double-draw. Geometry is "inverted" (reversed winding order) so we're drawing backfaces.
     },
-    blending: BlendingState.ALPHA_BLEND,
+    blending: BlendingState.PRE_MULTIPLIED_ALPHA_BLEND,
     depthMask: false,
     stencilTest: {
       enabled: mask3DTiles,

diff --git a/Source/Shaders/Vector3DTileClampedPolylinesFS.glsl b/Source/Shaders/Vector3DTileClampedPolylinesFS.glsl
@@ -48,5 +48,8 @@ void main()
     }
     gl_FragColor = u_highlightColor;
 
+    // Premultiply alpha. Required for classification primitives on translucent globe.
+    gl_FragColor.rgb *= gl_FragColor.a;
+
     czm_writeDepthClamp();
 }