Light propagation 2: Increase speed a little bit

src/scripts/light2/light.ts

@@ -26,13 +26,16 @@ export class LightPropagation2 extends GPUAbstractRunner {
     textureSrc: Texture
 
     bind_group_layout: GPUBindGroupLayout
-    bind_groupa: GPUBindGroup
-    bind_groupb: GPUBindGroup
+    bind_group_atob: GPUBindGroup
+    bind_group_btoa: GPUBindGroup
+
     scene_bind_group_layout: GPUBindGroupLayout
     scene_bind_group: GPUBindGroup
+
     pipeline_layout: GPUPipelineLayout
     compute_pipeline: GPUComputePipeline
     shader: GPUProgrammableStage
+
     stagingBuffer: Buffer
     stagingData: Float32Array
 
@@ -102,7 +105,7 @@ export class LightPropagation2 extends GPUAbstractRunner {
                 }]
         })
 
-        this.bind_groupa = GPU.device.createBindGroup({
+        this.bind_group_atob = GPU.device.createBindGroup({
             layout: this.bind_group_layout,
             entries: [{
                 binding: 0,
@@ -116,7 +119,7 @@ export class LightPropagation2 extends GPUAbstractRunner {
             }]
         })
 
-        this.bind_groupb = GPU.device.createBindGroup({
+        this.bind_group_btoa = GPU.device.createBindGroup({
             layout: this.bind_group_layout,
             entries: [{
                 binding: 0,
@@ -168,16 +171,16 @@ export class LightPropagation2 extends GPUAbstractRunner {
         GPU.device.queue.writeBuffer(this.stagingBuffer.buffer, 0, this.stagingData)
 
         let encoder: GPUCommandEncoder = GPU.device.createCommandEncoder({});
-        for(let i = 0; i < 60; i++) {
+        for(let i = 0; i < 80; i++) {
             let pass: GPUComputePassEncoder = encoder.beginComputePass();
-            pass.setBindGroup(0, this.bind_groupa);
+            pass.setBindGroup(0, this.bind_group_atob);
             pass.setBindGroup(1, this.scene_bind_group);
             pass.setPipeline(this.compute_pipeline);
             pass.dispatchWorkgroups(this.width / 8, this.height / 8);
             pass.end();
 
             pass = encoder.beginComputePass();
-            pass.setBindGroup(0, this.bind_groupb);
+            pass.setBindGroup(0, this.bind_group_btoa);
             pass.setBindGroup(1, this.scene_bind_group);
             pass.setPipeline(this.compute_pipeline);
             pass.dispatchWorkgroups(this.width / 8, this.height / 8);

src/scripts/light2/propagate.wgsl

@@ -62,6 +62,17 @@ fn retrieveConstants(pn: vec2i, F: ptr<function, ColorCH>,  E: ptr<function, Col
     */
 }
 
+    // note that sa2 = (90° - sa1) / 2
+    //const sa1: f32 = solid_angle(vec2f(1.5,      -0.5), vec2<f32>(1.5, 0.5)); // ~53.13°, projecting to the right side of our pixel
+    //const sa2: f32 = solid_angle(vec2f(0.5, 0.5), vec2<f32>(1.5, 0.5)); // ~18.43°, projecting to the top/bottom side of our pixel
+    //const dn1: vec2f = normalize(vec2f(2.,  1.0)); // normal to the center of the top side of our pixel
+
+    // TODO: the comments are wrong
+    const sa1= 0.6435011087932845; // ~53.13°, projecting to the right side of our pixel
+    const sa2= 0.4636476090008066; // ~18.43°, projecting to the top/bottom side of our pixel
+    const dn1 = vec2f(0.8944271909999159, 0.4472135954999579); // normal to the center of the top side of our pixel
+    const dn0 = vec2f(0.8944271909999159, -0.4472135954999579); // normal to the center of the bottom side of our pixel
+
 fn lpv_kernel(p: vec2i, out: ptr<function, ColorCH>) {
     let Em = textureLoad(scene, p, 0, 0).xyz; // emitted rgb light as circular harmonics
     let translucency = textureLoad(scene, p, 1, 0).w;
@@ -75,11 +86,6 @@ fn lpv_kernel(p: vec2i, out: ptr<function, ColorCH>) {
     let dn1: vec2f = normalize(vec2f(x - 0.5,  1.0)); // normal to the center of the top side of our pixel
     let dn0: vec2f = normalize(vec2f(x - 0.5, -1.0)); // normal to the center of the bottom side of our pixel
 */
-    let sa1: f32 = solid_angle(vec2f(1.5,      -0.5), vec2<f32>(1.5, 0.5)); // ~53.13°, projecting to the right side of our pixel
-    let sa2: f32 = solid_angle(vec2f(0.5, 0.5), vec2<f32>(1.5, 0.5)); // ~18.43°, projecting to the top/bottom side of our pixel
-    // note that sa2 = (90° - sa1) / 2
-    let dn1: vec2f = normalize(vec2f(2.,  1.0)); // normal to the center of the top side of our pixel
-    let dn0: vec2f = normalize(vec2f(2., -1.0)); // normal to the center of the bottom side of our pixel
 
 /*
 float sa1 = solid_angle(vec2(1.5, -0.5),vec2(1.5,0.5)); // ~53.13°, projecting to the right side of our pixel
@@ -98,14 +104,12 @@ float sa1 = solid_angle(vec2(1.5, -0.5),vec2(1.5,0.5)); // ~53.13°, projecting
     propagate(dn1,            sa2, F, E, out);
     propagate(dn0,            sa2, F, E, out);
 
-
     pn = p + vec2i(1, 0);
     retrieveConstants(pn, &F, &E);
     propagate(vec2f(-1., 0.), sa1, F, E, out);
     propagate(-dn0,           sa2, F, E, out);
     propagate(-dn1,           sa2, F, E, out);
 
-
     pn = p + vec2i(0, -1);
     retrieveConstants(pn, &F, &E);
     propagate(vec2f(0., 1.),  sa1, F, E, out);

src/scripts/light2/scene/scene.ts

@@ -43,7 +43,7 @@ export class LightScene {
 
         // 0: color emitter circular harmonics, z-component
         // 1: normal vector of the surface
-        this.emitter = GPU.CreateStorageTextureArray(this.width, this.height, 2,  "rgba16float")
+        this.emitter = GPU.CreateStorageTextureArray(this.width, this.height, 2,  "rgba8unorm")
 
         this.raytrace = new Raytrace("fbm.wgsl")
         try {

src/scripts/light2/scene/scene.wgsl

@@ -21,7 +21,7 @@ fn sphere(p: vec2<f32>, r: f32) -> f32 {
     return length(p) - r;
 }
 
-@group(0) @binding(0) var scene : texture_storage_2d_array<rgba16float, write>;
+@group(0) @binding(0) var scene : texture_storage_2d_array<rgba8unorm, write>;
 @group(0) @binding(1) var<uniform> staging: StagingBuffer;
 @group(0) @binding(2) var sdf : texture_2d<f32>;