Fix/gaussian splat flicker

CHANGES.md

@@ -7,6 +7,7 @@
 #### Fixes :wrench:
 
 - Materials loaded from type now respect submaterials present in the referenced material type. [#10566](https://github.com/CesiumGS/cesium/issues/10566)
+- Fix flickering artifact in Gaussian splat models caused by incorrect sorting results. [#12662](https://github.com/CesiumGS/cesium/issues/12662)
 
 #### Additions :tada:
 

CONTRIBUTORS.md

@@ -429,3 +429,4 @@ See [CONTRIBUTING.md](CONTRIBUTING.md) for details on how to contribute to Cesiu
 - [Matt Schwartz](https://github.com/mzschwartz5)
 - [Easy Mahaffey](https://github.com/easymaahffey)
 - [Pamela Augustine](https://github.com/pamelaAugustine)
+- [宋时旺](https://github.com/BlockCnFuture)

packages/engine/Source/Scene/GaussianSplatPrimitive.js

@@ -566,7 +566,7 @@ GaussianSplatPrimitive.generateSplatTexture = function (primitive, frameState) {
           },
         });
       }
-
+      primitive._vertexArray = undefined;
       primitive._lastTextureHeight = splatTextureData.height;
       primitive._lastTextureWidth = splatTextureData.width;
 
@@ -652,8 +652,9 @@ GaussianSplatPrimitive.buildGSplatDrawCommand = function (
 
   const uniformMap = renderResources.uniformMap;
 
+  const textureCache = primitive.gaussianSplatTexture;
   uniformMap.u_splatAttributeTexture = function () {
-    return primitive.gaussianSplatTexture;
+    return textureCache;
   };
 
   if (primitive._sphericalHarmonicsDegree > 0) {
@@ -768,12 +769,13 @@ GaussianSplatPrimitive.buildGSplatDrawCommand = function (
     scratchMatrix4B,
   );
 
+  const vertexArrayCache = primitive._vertexArray;
   const command = new DrawCommand({
     boundingVolume: tileset.boundingSphere,
     modelMatrix: modelMatrix,
     uniformMap: uniformMap,
     renderState: renderState,
-    vertexArray: primitive._vertexArray,
+    vertexArray: vertexArrayCache,
     shaderProgram: shaderProgram,
     cull: renderStateOptions.cull.enabled,
     pass: Pass.GAUSSIAN_SPLATS,