Update gsplat example shaders to latest structure (playcanvas#7021)

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

@@ -1,26 +1,34 @@
 uniform float uTime;
 varying float height;
 
-void main(void)
-{
-    // get splat color and alpha
-    gl_FragColor = evalSplat();
-
+void animate(inout vec4 clr) {
     float sineValue = abs(sin(uTime * 5.0 + height));
 
     #ifdef CUTOUT
 
         // in cutout mode, remove pixels along the wave
         if (sineValue < 0.5) {
-            gl_FragColor.a = 0.0;
+            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);
-        gl_FragColor.xyz = mix(gl_FragColor.xyz, gold, blend);
+        clr.xyz = mix(clr.xyz, gold, blend);
 
     #endif
 }
+
+varying mediump vec2 texCoord;
+varying mediump vec4 color;
+
+void main(void)
+{
+    vec4 clr = evalSplat(texCoord, color);
+
+    animate(clr);
+
+    gl_FragColor = clr;
+}

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

@@ -1,7 +1,7 @@
 uniform float uTime;
 varying float height;
 
-void animate() {
+void animate(inout vec3 center) {
     // modify center
     float heightIntensity = center.y * 0.2;
     center.x += sin(uTime * 5.0 + center.y) * 0.3 * heightIntensity;
@@ -10,7 +10,14 @@ void animate() {
     height = center.y;
 }
 
-vec4 discardVec = vec4(0.0, 0.0, 2.0, 1.0);
+uniform vec3 view_position;
+
+uniform sampler2D splatColor;
+
+varying mediump vec2 texCoord;
+varying mediump vec4 color;
+
+mediump vec4 discardVec = vec4(0.0, 0.0, 2.0, 1.0);
 
 void main(void)
 {
@@ -20,25 +27,53 @@ void main(void)
         return;
     }
 
-    // read data
-    readData();
+    // get center
+    vec3 center = getCenter();
 
-    // animate
-    animate();
+    animate(center);
 
-    vec4 pos;
-    if (!evalSplat(pos)) {
+    // 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) {
         gl_Position = discardVec;
         return;
     }
 
-    gl_Position = pos;
+    // get covariance
+    vec3 covA, covB;
+    getCovariance(covA, covB);
+
+    vec4 v1v2 = calcV1V2(splat_cam.xyz, covA, covB, transpose(mat3(model_view)));
 
-    texCoord = vertex_position.xy;
-    color = getColor();
+    // get color
+    color = texelFetch(splatColor, splatUV, 0);
+
+    // 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;
+    }
+
+    gl_Position = splat_proj + vec4((vertex_position.x * v1v2.xy + vertex_position.y * v1v2.zw) / viewport * splat_proj.w, 0, 0);
+
+    texCoord = vertex_position.xy * scale / 2.0;
+
+    #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
 
     #ifndef DITHER_NONE
         id = float(splatId);
     #endif
-
-}
+}

src/scene/gsplat/shader-generator-gsplat.js

@@ -120,17 +120,17 @@ const splatCoreVS = /* glsl */ `
     }
 
     // fetch quantized spherical harmonic coefficients
-    void fetchScale(in highp usampler2D sampler, out float scale, out vec3 a, out vec3 b, out vec3 c) {
-        uvec4 t = texelFetch(sampler, splatUV, 0);
+    void fetchScale(in highp usampler2D s, out float scale, out vec3 a, out vec3 b, out vec3 c) {
+        uvec4 t = texelFetch(s, splatUV, 0);
         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;
     }
 
     // fetch quantized spherical harmonic coefficients
-    void fetch(in highp usampler2D sampler, out vec3 a, out vec3 b, out vec3 c, out vec3 d) {
-        uvec4 t = texelFetch(sampler, splatUV, 0);
+    void fetch(in highp usampler2D s, out vec3 a, out vec3 b, out vec3 c, out vec3 d) {
+        uvec4 t = texelFetch(s, splatUV, 0);
         a = unpack111011(t.x) * 2.0 - 1.0;
         b = unpack111011(t.y) * 2.0 - 1.0;
         c = unpack111011(t.z) * 2.0 - 1.0;