Adding some more comments. Destructuring the context object in the pass modules. A little code cleanup in bloomPass. Changing the endPass sampler to be cheaper.

TODO.txt

@@ -1,7 +1,6 @@
 TODO:
 
 WebGPU
-  Make sure everything is properly commented
   Update links in issues
   Get rid of end pass once it's possible to copy a bgra8unorm to a canvas texture
   Switch to rgba32float somehow?

js/regl/bloomPass.js

@@ -1,7 +1,7 @@
 import { loadText, makePassFBO, makePass } from "./utils.js";
 
 // The bloom pass is basically an added high-pass blur.
-// The blur approximation is the sum of a pyramid of downscaled textures.
+// The blur approximation is the sum of a pyramid of downscaled, blurred textures.
 
 const pyramidHeight = 5;
 const levelStrengths = Array(pyramidHeight)

js/webgpu/bloomPass.js

@@ -1,19 +1,20 @@
 import { structs } from "/lib/gpu-buffer.js";
 import { makeComputeTarget, makePyramidView, loadShader, makeUniformBuffer, makeBindGroup, makePass } from "./utils.js";
 
-export default (context) => {
-	const { config, device } = context;
+// The bloom pass is basically an added blur of the rain pass's high-pass output.
+// The blur approximation is the sum of a pyramid of downscaled, blurred textures.
 
+export default ({ config, device }) => {
 	const pyramidHeight = 4;
 	const bloomSize = config.bloomSize;
 	const bloomStrength = config.bloomStrength;
 	const bloomRadius = 2; // Looks better with more, but is more costly
 
-	const enabled = true;
+	const enabled = bloomSize > 0 && bloomStrength > 0;
 
 	// If there's no bloom to apply, return a no-op pass with an empty bloom texture
 	if (!enabled) {
-		const emptyTexture = makeComputeTarget(device, 1, 1);
+		const emptyTexture = makeComputeTarget(device, [1, 1]);
 		return makePass(null, (size, inputs) => ({ ...inputs, bloom: emptyTexture }));
 	}
 
@@ -24,6 +25,8 @@ export default (context) => {
 		minFilter: "linear",
 	});
 
+	// The blur pipeline applies a blur in one direction; it's applied horizontally
+	// to the first image pyramid, and then vertically to the second image pyramid.
 	let blurPipeline;
 	let hBlurPyramid;
 	let vBlurPyramid;
@@ -31,6 +34,8 @@ export default (context) => {
 	let vBlurBuffer;
 	let hBlurBindGroups;
 	let vBlurBindGroups;
+
+	// The combine pipeline blends the last image pyramid's layers into the output.
 	let combinePipeline;
 	let combineBuffer;
 	let combineBindGroup;
@@ -63,6 +68,8 @@ export default (context) => {
 	})();
 
 	const build = (screenSize, inputs) => {
+
+		// Since the bloom is blurry, we downscale everything
 		scaledScreenSize = screenSize.map((x) => Math.floor(x * bloomSize));
 
 		hBlurPyramid?.destroy();
@@ -74,17 +81,18 @@ export default (context) => {
 		output?.destroy();
 		output = makeComputeTarget(device, scaledScreenSize);
 
-		const hBlurPyramidViews = [];
-		const vBlurPyramidViews = [];
 		hBlurBindGroups = [];
 		vBlurBindGroups = [];
 
+		// The first pyramid's level 1 texture is the input texture blurred.
+		// The subsequent levels of the pyramid are the preceding level blurred.
+		let srcView = inputs.highPass.createView();
 		for (let i = 0; i < pyramidHeight; i++) {
-			hBlurPyramidViews[i] = makePyramidView(hBlurPyramid, i);
-			vBlurPyramidViews[i] = makePyramidView(vBlurPyramid, i);
-			const srcView = i === 0 ? inputs.highPass.createView() : hBlurPyramidViews[i - 1];
-			hBlurBindGroups[i] = makeBindGroup(device, blurPipeline, 0, [hBlurBuffer, linearSampler, srcView, hBlurPyramidViews[i]]);
-			vBlurBindGroups[i] = makeBindGroup(device, blurPipeline, 0, [vBlurBuffer, linearSampler, hBlurPyramidViews[i], vBlurPyramidViews[i]]);
+			const hBlurPyramidView = makePyramidView(hBlurPyramid, i);
+			const vBlurPyramidView = makePyramidView(vBlurPyramid, i);
+			hBlurBindGroups[i] = makeBindGroup(device, blurPipeline, 0, [hBlurBuffer, linearSampler, srcView, hBlurPyramidView]);
+			vBlurBindGroups[i] = makeBindGroup(device, blurPipeline, 0, [vBlurBuffer, linearSampler, hBlurPyramidView, vBlurPyramidView]);
+			srcView = hBlurPyramidView;
 		}
 
 		combineBindGroup = makeBindGroup(device, combinePipeline, 0, [combineBuffer, linearSampler, vBlurPyramid.createView(), output.createView()]);
@@ -100,8 +108,11 @@ export default (context) => {
 
 		computePass.setPipeline(blurPipeline);
 		for (let i = 0; i < pyramidHeight; i++) {
-			const downsample = 2 ** -i;
-			const dispatchSize = [Math.ceil(Math.floor(scaledScreenSize[0] * downsample) / 32), Math.floor(Math.floor(scaledScreenSize[1] * downsample)), 1];
+			const dispatchSize = [
+				Math.ceil(Math.floor(scaledScreenSize[0] * 2 ** -i) / 32),
+				Math.floor(Math.floor(scaledScreenSize[1] * 2 ** -i)),
+				1
+			];
 			computePass.setBindGroup(0, hBlurBindGroups[i]);
 			computePass.dispatch(...dispatchSize);
 			computePass.setBindGroup(0, vBlurBindGroups[i]);

js/webgpu/endPass.js

@@ -1,14 +1,12 @@
 import { loadShader, makeBindGroup, makePass } from "./utils.js";
 
+// Eventually, WebGPU will allow the output of the final pass in the pipeline to be copied to the canvas texture.
+// Until then, this render pass does the job.
+
 const numVerticesPerQuad = 2 * 3;
 
-export default (context) => {
-	const { config, device, canvasFormat, canvasContext } = context;
-
-	const linearSampler = device.createSampler({
-		magFilter: "linear",
-		minFilter: "linear",
-	});
+export default ({ device, canvasFormat, canvasContext }) => {
+	const nearestSampler = device.createSampler();
 
 	const renderPassConfig = {
 		colorAttachments: [
@@ -46,7 +44,7 @@ export default (context) => {
 	})();
 
 	const build = (size, inputs) => {
-		renderBindGroup = makeBindGroup(device, renderPipeline, 0, [linearSampler, inputs.primary.createView()]);
+		renderBindGroup = makeBindGroup(device, renderPipeline, 0, [nearestSampler, inputs.primary.createView()]);
 		return null;
 	};
 

js/webgpu/imagePass.js

@@ -4,9 +4,7 @@ import { makeComputeTarget, loadTexture, loadShader, makeBindGroup, makePass } f
 
 const defaultBGURL = "https://upload.wikimedia.org/wikipedia/commons/thumb/0/0a/Flammarion_Colored.jpg/917px-Flammarion_Colored.jpg";
 
-export default (context) => {
-	const { config, device } = context;
-
+export default ({ config, device }) => {
 	const bgURL = "bgURL" in config ? config.bgURL : defaultBGURL;
 	const assets = [loadTexture(device, bgURL), loadShader(device, "shaders/wgsl/imagePass.wgsl")];
 

js/webgpu/palettePass.js

@@ -75,9 +75,7 @@ const makePalette = (device, paletteUniforms, entries) => {
 // won't persist across subsequent frames. This is a safe trick
 // in screen space.
 
-export default (context) => {
-	const { config, device, timeBuffer } = context;
-
+export default ({ config, device, timeBuffer }) => {
 	const linearSampler = device.createSampler({
 		magFilter: "linear",
 		minFilter: "linear",

js/webgpu/rainPass.js

@@ -31,9 +31,7 @@ const makeConfigBuffer = (device, configUniforms, config, density, gridSize) =>
 	return makeUniformBuffer(device, configUniforms, configData);
 };
 
-export default (context) => {
-	const { config, device, timeBuffer, canvasFormat } = context;
-
+export default ({ config, device, timeBuffer, canvasFormat }) => {
 	const assets = [loadTexture(device, config.glyphTexURL), loadShader(device, "shaders/wgsl/rainPass.wgsl")];
 
 	// The volumetric mode multiplies the number of columns

js/webgpu/resurrectionPass.js

@@ -11,9 +11,7 @@ import { loadShader, makeUniformBuffer, makeComputeTarget, makeBindGroup, makePa
 
 const numVerticesPerQuad = 2 * 3;
 
-export default (context) => {
-	const { config, device, timeBuffer } = context;
-
+export default ({ config, device, timeBuffer }) => {
 	const linearSampler = device.createSampler({
 		magFilter: "linear",
 		minFilter: "linear",

js/webgpu/stripePass.js

@@ -37,9 +37,7 @@ const numVerticesPerQuad = 2 * 3;
 // won't persist across subsequent frames. This is a safe trick
 // in screen space.
 
-export default (context, getInputs) => {
-	const { config, device, timeBuffer } = context;
-
+export default ({ config, device, timeBuffer }) => {
 	// Expand and convert stripe colors into 1D texture data
 	const input =
 		"stripeColors" in config ? config.stripeColors.split(",").map(parseFloat) : config.effect === "pride" ? prideStripeColors : transPrideStripeColors;

shaders/wgsl/endPass.wgsl

@@ -1,4 +1,4 @@
-[[group(0), binding(0)]] var linearSampler : sampler;
+[[group(0), binding(0)]] var nearestSampler : sampler;
 [[group(0), binding(1)]] var tex : texture_2d<f32>;
 
 struct VertOutput {
@@ -15,5 +15,5 @@ struct VertOutput {
 [[stage(fragment)]] fn fragMain(input : VertOutput) -> [[location(0)]] vec4<f32> {
 	var uv = input.uv;
 	uv.y = 1.0 - uv.y;
-	return textureSample( tex, linearSampler, uv );
+	return textureSample( tex, nearestSampler, uv );
 }