shader updates improves performance and visual quality

removing legacy _opacity attribute support
CesiumGS · Oct 25, 2024 · f207786 · f207786
1 parent 52b3d61
commit f207786
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Showing 5 changed files with 37 additions and 22 deletions.
diff --git a/packages/engine/Source/Scene/Model/GaussianSplatPipelineStage.js b/packages/engine/Source/Scene/Model/GaussianSplatPipelineStage.js
@@ -34,11 +34,13 @@ GaussianSplatPipelineStage.process = function (
   shaderBuilder.addAttribute("vec2", "a_screenQuadPosition");
   shaderBuilder.addAttribute("vec3", "a_splatPosition");
   shaderBuilder.addAttribute("vec4", "a_splatColor");
-  shaderBuilder.addAttribute("float", "a_splatOpacity");
+  //shaderBuilder.addAttribute("float", "a_splatOpacity");
 
   shaderBuilder.addVarying("vec4", "v_splatColor");
   shaderBuilder.addVarying("vec2", "v_vertPos");
   shaderBuilder.addVarying("float", "v_splatOpacity");
+  shaderBuilder.addVarying("vec4", "v_splatScale");
+  shaderBuilder.addVarying("vec4", "v_splatRot");
 
   shaderBuilder.addUniform("float", "u_tan_fovX", ShaderDestination.VERTEX);
   shaderBuilder.addUniform("float", "u_tan_fovY", ShaderDestination.VERTEX);
@@ -86,19 +88,19 @@ GaussianSplatPipelineStage.process = function (
     const scaleAttr = attributes.find((a) => a.name === "_SCALE");
     const rotAttr = attributes.find((a) => a.name === "_ROTATION");
     const clrAttr = attributes.find((a) => a.name === "COLOR_0");
-    // const opAttr = attributes.find((a) => a.name === "_OPACITY");
+    //  const opAttr = attributes.find((a) => a.name === "_OPACITY");
 
     const posArray = posAttr.typedArray;
     const scaleArray = scaleAttr.typedArray;
     const rotArray = rotAttr.typedArray;
     const clrArray = clrAttr.typedArray;
-    //  const opArray = opAttr.typedArray;
+    //    const opArray = opAttr.typedArray;
 
     const newPosArray = new posArray.constructor(posArray.length);
     const newScaleArray = new scaleArray.constructor(scaleArray.length);
     const newRotArray = new rotArray.constructor(rotArray.length);
     const newClrArray = new clrArray.constructor(clrArray.length);
-    //  const newOpArray = new opArray.constructor(opArray.length);
+    //   const newOpArray = new opArray.constructor(opArray.length);
 
     const calcDepth = (i) =>
       posArray[i * 3] * modelView[2] +
@@ -149,11 +151,12 @@ GaussianSplatPipelineStage.process = function (
       newRotArray[i * 4 + 2] = rotArray[j * 4 + 2];
       newRotArray[i * 4 + 3] = rotArray[j * 4 + 3];
 
-      newClrArray[i * 3] = clrArray[j * 3];
-      newClrArray[i * 3 + 1] = clrArray[j * 3 + 1];
-      newClrArray[i * 3 + 2] = clrArray[j * 3 + 2];
+      newClrArray[i * 4] = clrArray[j * 4];
+      newClrArray[i * 4 + 1] = clrArray[j * 4 + 1];
+      newClrArray[i * 4 + 2] = clrArray[j * 4 + 2];
+      newClrArray[i * 4 + 3] = clrArray[j * 4 + 3];
 
-      //    newOpArray[i] = opArray[j];
+      // newOpArray[i] = opArray[j];
     }
 
     posAttr.typedArray = newPosArray;

diff --git a/packages/engine/Source/Scene/Model/GeometryPipelineStage.js b/packages/engine/Source/Scene/Model/GeometryPipelineStage.js
@@ -148,9 +148,6 @@ GeometryPipelineStage.process = function (
         showSplats ? 1 : 0;
       primitive.attributes.find((a) => a.name === "COLOR_0").instanceDivisor =
         showSplats ? 1 : 0;
-      // primitive.attributes.find(
-      //   (a) => a.name === "_OPACITY"
-      // ).instanceDivisor = showSplats ? 1 : 0;
 
       if (!showSplats) {
         shaderBuilder.addDefine("PRIMITIVE_TYPE_POINTS");

diff --git a/packages/engine/Source/Scene/Model/ModelDrawCommands.js b/packages/engine/Source/Scene/Model/ModelDrawCommands.js
@@ -125,7 +125,9 @@ function buildDrawCommandForModel(
         screenQuadPosition: 0,
         splatPosition: 6,
         splatColor: 7,
-        splatOpacity: 8,
+        // splatScale:8,
+        // splatRot:9
+        //      splatOpacity: 8,
       };
       const geometry = new Geometry({
         attributes: {
@@ -151,6 +153,20 @@ function buildDrawCommandForModel(
             name: "_SPLAT_COLOR",
             variableName: "splatColor",
           },
+          // splatScale: {
+          //   ...primitiveRenderResources.runtimePrimitive.primitive.attributes.find(
+          //     (a) => a.name === "_SCALE",
+          //   ),
+          //   name: "_SPLAT_SCALE",
+          //   variableName: "splatScale"
+          // },
+          // splatRot: {
+          //   ...primitiveRenderResources.runtimePrimitive.primitive.attributes.find(
+          //     (a) => a.name === "_ROTATION",
+          //   ),
+          //   name: "_SPLAT_ROTATION",
+          //   variableName: "splatRot"
+          // }
           // splatOpacity: {
           //   ...primitiveRenderResources.runtimePrimitive.primitive.attributes.find(
           //     (a) => a.name === "_OPACITY"

diff --git a/packages/engine/Source/Shaders/Model/GaussianSplatFS.glsl b/packages/engine/Source/Shaders/Model/GaussianSplatFS.glsl
@@ -1,8 +1,9 @@
 void gaussianSplatStage(inout vec4 color, in ProcessedAttributes attributes) {
-    float A = -dot(v_vertPos, v_vertPos);
-    if(A < -4.0)
+    float A = dot(v_vertPos, v_vertPos);
+    if(A > 2.0)
         discard;
-    float B = exp(A) * v_splatColor.a;
-    color = vec4(v_splatColor.rgb * B , B);
+
+    float B = exp(-A * 2.5) * v_splatColor.a;
+    color = vec4(v_splatColor.rgb * B, B);
 }
 
diff --git a/packages/engine/Source/Shaders/Model/GaussianSplatVS.glsl b/packages/engine/Source/Shaders/Model/GaussianSplatVS.glsl
@@ -68,7 +68,7 @@ vec3 calcCov2D(vec3 worldPos, float focal_x, float focal_y, float tan_fovx, floa
 void gaussianSplatStage(ProcessedAttributes attributes, inout vec4 positionClip) {
     mat4 viewMatrix = czm_modelView;
 
-    vec4 clipPosition = czm_modelViewProjection * vec4(a_splatPosition,1.0);
+    vec4 clipPosition = czm_modelViewProjection * vec4(a_splatPosition ,1.0);
     positionClip = clipPosition;
 
     float[6] cov3D;
@@ -85,12 +85,10 @@ void gaussianSplatStage(ProcessedAttributes attributes, inout vec4 positionClip)
     vec2 minorAxis = min(sqrt(2.0 * lambda2), 1024.0) * vec2(diagonalVector.y, -diagonalVector.x);
 
     vec2 corner = vec2((gl_VertexID << 1) & 2, gl_VertexID & 2) - 1.;
-    corner *= 2.0;
 
-    vec2 deltaScreenPos = (corner.x * majorAxis + corner.y * minorAxis) * 2.0 / czm_viewport.zw;
-    positionClip.xy += deltaScreenPos * positionClip.w;
-    v_vertPos = corner;
+    positionClip += vec4((corner.x * majorAxis + corner.y * minorAxis) * 4.0 / czm_viewport.zw * positionClip.w, 0, 0);
+    positionClip.z = clamp(positionClip.z, -abs(positionClip.w), abs(positionClip.w));
+    v_vertPos = corner ;
     v_splatColor = a_splatColor;
-    v_splatOpacity = a_splatOpacity;
 }