Convert gsplat material to use chunks (#7164)

Author: slimbuck

examples/src/examples/loaders/gsplat-many.example.mjs

@@ -71,7 +71,6 @@ assetListLoader.load(() => {
 
     // instantiate guitar with a custom shader
     const guitar = assets.guitar.resource.instantiate({
-        fragment: files['shader.frag'],
         vertex: files['shader.vert']
     });
     guitar.name = 'guitar';

examples/src/examples/loaders/gsplat-many.shader.frag

@@ -1,79 +1,78 @@
+#include "gsplatCommonVS"
+
+varying mediump vec2 gaussianUV;
+varying mediump vec4 gaussianColor;
+
+#ifndef DITHER_NONE
+    varying float id;
+#endif
+
+mediump vec4 discardVec = vec4(0.0, 0.0, 2.0, 1.0);
+
 uniform float uTime;
-varying float height;
 
-void animate(inout vec3 center) {
+vec3 animatePosition(vec3 center) {
     // modify center
     float heightIntensity = center.y * 0.2;
     center.x += sin(uTime * 5.0 + center.y) * 0.3 * heightIntensity;
 
     // output y-coordinate
-    height = center.y;
+    return center;
 }
 
-uniform vec3 view_position;
-
-uniform sampler2D splatColor;
-
-varying mediump vec2 texCoord;
-varying mediump vec4 color;
+vec4 animateColor(float height, vec4 clr) {
+    float sineValue = abs(sin(uTime * 5.0 + height));
+
+    #ifdef CUTOUT
+        // in cutout mode, remove pixels along the wave
+        if (sineValue < 0.5) {
+            clr.a = 0.0;
+        }
+    #else
+        // in non-cutout mode, add a golden tint to the wave
+        vec3 gold = vec3(1.0, 0.85, 0.0);
+        float blend = smoothstep(0.9, 1.0, sineValue);
+        clr.xyz = mix(clr.xyz, gold, blend);
+    #endif
 
-mediump vec4 discardVec = vec4(0.0, 0.0, 2.0, 1.0);
+    return clr;
+}
 
-void main(void)
-{
-    // calculate splat uv
-    if (!calcSplatUV()) {
+void main(void) {
+    // read gaussian center
+    SplatState state;
+    if (!readCenter(state)) {
         gl_Position = discardVec;
         return;
     }
 
-    // get center
-    vec3 center = getCenter();
-
-    animate(center);
+    state.center = animatePosition(state.center);
 
-    // handle transforms
-    mat4 model_view = matrix_view * matrix_model;
-    vec4 splat_cam = model_view * vec4(center, 1.0);
-    vec4 splat_proj = matrix_projection * splat_cam;
-
-    // cull behind camera
-    if (splat_proj.z < -splat_proj.w) {
+    // project center to screen space
+    ProjectedState projState;
+    if (!projectCenter(state, projState)) {
         gl_Position = discardVec;
         return;
     }
 
-    // get covariance
-    vec3 covA, covB;
-    getCovariance(covA, covB);
-
-    vec4 v1v2 = calcV1V2(splat_cam.xyz, covA, covB, transpose(mat3(model_view)));
-
-    // get color
-    color = texelFetch(splatColor, splatUV, 0);
+    // read color
+    vec4 clr = readColor(state);
 
-    // calculate scale based on alpha
-    float scale = min(1.0, sqrt(-log(1.0 / 255.0 / color.a)) / 2.0);
-
-    v1v2 *= scale;
-
-    // early out tiny splats
-    if (dot(v1v2.xy, v1v2.xy) < 4.0 && dot(v1v2.zw, v1v2.zw) < 4.0) {
-        gl_Position = discardVec;
-        return;
-    }
+    // evaluate spherical harmonics
+    #if SH_BANDS > 0
+        clr.xyz = max(clr.xyz + evalSH(state, projState), 0.0);
+    #endif
 
-    gl_Position = splat_proj + vec4((vertex_position.x * v1v2.xy + vertex_position.y * v1v2.zw) / viewport * splat_proj.w, 0, 0);
+    clr = animateColor(state.center.y, clr);
 
-    texCoord = vertex_position.xy * scale / 2.0;
+    applyClipping(projState, clr.w);
 
-    #ifdef USE_SH1
-        vec4 worldCenter = matrix_model * vec4(center, 1.0);
-        vec3 viewDir = normalize((worldCenter.xyz / worldCenter.w - view_position) * mat3(matrix_model));
-        color.xyz = max(color.xyz + evalSH(viewDir), 0.0);
-    #endif
+    // write output
+    gl_Position = projState.cornerProj;
+    gaussianUV = projState.cornerUV;
+    gaussianColor = vec4(prepareOutputFromGamma(clr.xyz), clr.w);
 
     #ifndef DITHER_NONE
-        id = float(splatId);
+        id = float(state.id);
     #endif
-}
+}

examples/src/examples/loaders/gsplat-many.shader.vert

@@ -5,6 +5,9 @@
  * @returns {number} Hash value.
  */
 function hashCode(str) {
+    if (str === null || str === undefined) {
+        return 0;
+    }
     let hash = 0;
     for (let i = 0, len = str.length; i < len; i++) {
         hash = ((hash << 5) - hash) + str.charCodeAt(i);