Write seed properly into UBO buffer

webgpu · Oct 28, 2024 · ca21d60 · ca21d60
1 parent f371d0e
commit ca21d60
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Showing 2 changed files with 3 additions and 4 deletions.
diff --git a/sample/particles/main.ts b/sample/particles/main.ts
@@ -327,7 +327,7 @@ const simulationParams = {
 const simulationUBOBufferSize =
   1 * 4 + // deltaTime
   1 * 4 + // brightnessFactor
-  3 * 4 + // padding
+  2 * 4 + // padding
   4 * 4 + // seed
   0;
 const simulationUBOBuffer = device.createBuffer({
@@ -411,7 +411,6 @@ function frame() {
       simulationParams.simulate ? simulationParams.deltaTime : 0.0,
       simulationParams.brightnessFactor,
       0.0,
-      0.0,
       0.0, // padding
       Math.random() * 100,
       Math.random() * 100, // seed.xy

diff --git a/sample/particles/particle.wgsl b/sample/particles/particle.wgsl
@@ -5,8 +5,8 @@ var<private> rand_seed : vec2f;
 
 fn init_rand(invocation_id : u32, seed : vec4f) {
   rand_seed = seed.xz;
-  rand_seed = fract(rand_seed * cos(35.456+f32(invocation_id) * seed.yw * 0.01f));
-  rand_seed = fract(rand_seed * cos(41.235+f32(invocation_id) * seed.xw * 0.01f));
+  rand_seed = fract(rand_seed * cos(35.456+f32(invocation_id) * seed.yw));
+  rand_seed = fract(rand_seed * cos(41.235+f32(invocation_id) * seed.xw));
 }
 
 fn rand() -> f32 {