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playcanvas · Dec 4, 2024 · 2863700 · 2863700
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Showing 3 changed files with 33 additions and 45 deletions.
diff --git a/src/scene/shader-lib/chunks/gsplat/vert/gsplatCommon.js b/src/scene/shader-lib/chunks/gsplat/vert/gsplatCommon.js
@@ -176,7 +176,8 @@ vec3 evalSH(in SplatState state, in ProjectedState projState) {
 
     // read sh coefficients
     vec3 sh[SH_COEFFS];
-    readSHData(state, sh);
+    float scale;
+    readSHData(state, sh, scale);
 
     // calculate the model-space view direction
     vec3 dir = normalize(projState.centerCam * mat3(projState.modelView));
@@ -217,7 +218,7 @@ vec3 evalSH(in SplatState state, in ProjectedState projState) {
         sh[14] * (SH_C3_6 * x * (xx - 3.0 * yy));
 #endif
 
-    return result;
+    return result * scale;
 }
 #endif
 `;
diff --git a/src/scene/shader-lib/chunks/gsplat/vert/gsplatCompressedSH.js b/src/scene/shader-lib/chunks/gsplat/vert/gsplatCompressedSH.js
@@ -5,30 +5,30 @@ uniform highp usampler2D shTexture0;
 uniform highp usampler2D shTexture1;
 uniform highp usampler2D shTexture2;
 
-vec4 sunpack8888(in uint bits) {
+vec4 unpack8888s(in uint bits) {
     return vec4((uvec4(bits) >> uvec4(0u, 8u, 16u, 24u)) & 0xffu) * (8.0 / 255.0) - 4.0;
 }
 
-void readSHData(in SplatState state, out vec3 sh[15]) {
+void readSHData(in SplatState state, out vec3 sh[15], out float scale) {
     // read the sh coefficients
     uvec4 shData0 = texelFetch(shTexture0, state.uv, 0);
     uvec4 shData1 = texelFetch(shTexture1, state.uv, 0);
     uvec4 shData2 = texelFetch(shTexture2, state.uv, 0);
 
-    vec4 r0 = sunpack8888(shData0.x);
-    vec4 r1 = sunpack8888(shData0.y);
-    vec4 r2 = sunpack8888(shData0.z);
-    vec4 r3 = sunpack8888(shData0.w);
+    vec4 r0 = unpack8888s(shData0.x);
+    vec4 r1 = unpack8888s(shData0.y);
+    vec4 r2 = unpack8888s(shData0.z);
+    vec4 r3 = unpack8888s(shData0.w);
 
-    vec4 g0 = sunpack8888(shData1.x);
-    vec4 g1 = sunpack8888(shData1.y);
-    vec4 g2 = sunpack8888(shData1.z);
-    vec4 g3 = sunpack8888(shData1.w);
+    vec4 g0 = unpack8888s(shData1.x);
+    vec4 g1 = unpack8888s(shData1.y);
+    vec4 g2 = unpack8888s(shData1.z);
+    vec4 g3 = unpack8888s(shData1.w);
 
-    vec4 b0 = sunpack8888(shData2.x);
-    vec4 b1 = sunpack8888(shData2.y);
-    vec4 b2 = sunpack8888(shData2.z);
-    vec4 b3 = sunpack8888(shData2.w);
+    vec4 b0 = unpack8888s(shData2.x);
+    vec4 b1 = unpack8888s(shData2.y);
+    vec4 b2 = unpack8888s(shData2.z);
+    vec4 b3 = unpack8888s(shData2.w);
 
     sh[0] =  vec3(r0.x, g0.x, b0.x);
     sh[1] =  vec3(r0.y, g0.y, b0.y);
@@ -45,6 +45,8 @@ void readSHData(in SplatState state, out vec3 sh[15]) {
     sh[12] = vec3(r3.x, g3.x, b3.x);
     sh[13] = vec3(r3.y, g3.y, b3.y);
     sh[14] = vec3(r3.z, g3.z, b3.z);
+
+    scale = 1.0;
 }
 
 #endif

diff --git a/src/scene/shader-lib/chunks/gsplat/vert/gsplatSH.js b/src/scene/shader-lib/chunks/gsplat/vert/gsplatSH.js
@@ -2,70 +2,55 @@ export default /* glsl */`
 
 #if SH_BANDS > 0
 
-vec3 unpack111011(uint bits) {
-    return vec3(
-        float(bits >> 21u) / 2047.0,
-        float((bits >> 11u) & 0x3ffu) / 1023.0,
-        float(bits & 0x7ffu) / 2047.0
-    );
+// unpack signed 11 10 11 bits
+vec3 unpack111011s(uint bits) {
+    return vec3((uvec3(bits) >> uvec3(21u, 11u, 0u)) & uvec3(0x7ffu, 0x3ffu, 0x7ffu)) / vec3(2047.0, 1023.0, 2047.0) * 2.0 - 1.0;
 }
 
 // fetch quantized spherical harmonic coefficients
 void fetchScale(in uvec4 t, out float scale, out vec3 a, out vec3 b, out vec3 c) {
     scale = uintBitsToFloat(t.x);
-    a = unpack111011(t.y) * 2.0 - 1.0;
-    b = unpack111011(t.z) * 2.0 - 1.0;
-    c = unpack111011(t.w) * 2.0 - 1.0;
+    a = unpack111011s(t.y);
+    b = unpack111011s(t.z);
+    c = unpack111011s(t.w);
 }
 
 // fetch quantized spherical harmonic coefficients
 void fetch(in uvec4 t, out vec3 a, out vec3 b, out vec3 c, out vec3 d) {
-    a = unpack111011(t.x) * 2.0 - 1.0;
-    b = unpack111011(t.y) * 2.0 - 1.0;
-    c = unpack111011(t.z) * 2.0 - 1.0;
-    d = unpack111011(t.w) * 2.0 - 1.0;
+    a = unpack111011s(t.x);
+    b = unpack111011s(t.y);
+    c = unpack111011s(t.z);
+    d = unpack111011s(t.w);
 }
 
 void fetch(in uint t, out vec3 a) {
-    a = unpack111011(t) * 2.0 - 1.0;
+    a = unpack111011s(t);
 }
 
 #if SH_BANDS == 1
     uniform highp usampler2D splatSH_1to3;
-    void readSHData(in SplatState state, out vec3 sh[3]) {
-        float scale;
+    void readSHData(in SplatState state, out vec3 sh[3], out float scale) {
         fetchScale(texelFetch(splatSH_1to3, state.uv, 0), scale, sh[0], sh[1], sh[2]);
-        for (int i = 0; i < 3; i++) {
-            sh[i] *= scale;
-        }
     }
 #elif SH_BANDS == 2
     uniform highp usampler2D splatSH_1to3;
     uniform highp usampler2D splatSH_4to7;
     uniform highp usampler2D splatSH_8to11;
-    void readSHData(in SplatState state, out vec3 sh[8]) {
-        float scale;
+    void readSHData(in SplatState state, out vec3 sh[8], out float scale) {
         fetchScale(texelFetch(splatSH_1to3, state.uv, 0), scale, sh[0], sh[1], sh[2]);
         fetch(texelFetch(splatSH_4to7, state.uv, 0), sh[3], sh[4], sh[5], sh[6]);
         fetch(texelFetch(splatSH_8to11, state.uv, 0).x, sh[7]);
-        for (int i = 0; i < 8; i++) {
-            sh[i] *= scale;
-        }
     }
 #else
     uniform highp usampler2D splatSH_1to3;
     uniform highp usampler2D splatSH_4to7;
     uniform highp usampler2D splatSH_8to11;
     uniform highp usampler2D splatSH_12to15;
-    void readSHData(in SplatState state, out vec3 sh[15]) {
-        float scale;
+    void readSHData(in SplatState state, out vec3 sh[15], out float scale) {
         fetchScale(texelFetch(splatSH_1to3, state.uv, 0), scale, sh[0], sh[1], sh[2]);
         fetch(texelFetch(splatSH_4to7, state.uv, 0), sh[3], sh[4], sh[5], sh[6]);
         fetch(texelFetch(splatSH_8to11, state.uv, 0), sh[7], sh[8], sh[9], sh[10]);
         fetch(texelFetch(splatSH_12to15, state.uv, 0), sh[11], sh[12], sh[13], sh[14]);
-        for (int i = 0; i < 15; i++) {
-            sh[i] *= scale;
-        }
     }
 #endif