From c27c20f2cf37b7618f412c9a5e8ba28dcc8e5a23 Mon Sep 17 00:00:00 2001
From: Rezmason <jeremysachs@rezmason.net>
Date: Wed, 27 Oct 2021 21:08:20 -0700
Subject: [PATCH] Consolidating all the bind groups, because I only have four.
 Stuff shared between render passes will get isolated somehow, but it might be
 by binding one buffer to multiple render passes' bind group at zero rather
 than having more than one bind group.

---
 js/webgpu_main.js           | 40 ++++++++++---------------------------
 shaders/rainRenderPass.wgsl | 10 +++++-----
 webgpu_notes.txt            |  2 ++
 3 files changed, 17 insertions(+), 35 deletions(-)

diff --git a/js/webgpu_main.js b/js/webgpu_main.js
index ad0f6f4..7e8a063 100644
--- a/js/webgpu_main.js
+++ b/js/webgpu_main.js
@@ -105,7 +105,7 @@ export default async (canvas, config) => {
 		const aspectRatio = canvasSize[0] / canvasSize[1];
 		const screenSize = aspectRatio > 1 ? [1, aspectRatio] : [1 / aspectRatio, 1];
 		queue.writeBuffer(cameraBuffer, 0, new Float32Array(screenSize));
-	}
+	};
 	updateCameraBuffer();
 
 	const [rainRenderShader] = await Promise.all(["shaders/rainRenderPass.wgsl"].map(async (path) => (await fetch(path)).text()));
@@ -145,7 +145,9 @@ export default async (canvas, config) => {
 		},
 	});
 
-	const configBindGroup = device.createBindGroup({
+	console.log(device.limits);
+
+	const bindGroup = device.createBindGroup({
 		layout: rainRenderPipeline.getBindGroupLayout(0),
 		entries: [
 			{
@@ -154,46 +156,28 @@ export default async (canvas, config) => {
 					buffer: configBuffer,
 				},
 			},
-		],
-	});
-
-	const msdfBindGroup = device.createBindGroup({
-		layout: rainRenderPipeline.getBindGroupLayout(1),
-		entries: [
 			{
-				binding: 0,
+				binding: 1,
 				resource: {
 					buffer: msdfBuffer,
 				},
 			},
 			{
-				binding: 1,
+				binding: 2,
 				resource: sampler,
 			},
 			{
-				binding: 2,
+				binding: 3,
 				resource: msdfTexture.createView(),
 			},
-		],
-	});
-
-	const timeBindGroup = device.createBindGroup({
-		layout: rainRenderPipeline.getBindGroupLayout(2),
-		entries: [
 			{
-				binding: 0,
+				binding: 4,
 				resource: {
 					buffer: timeBuffer,
 				},
 			},
-		],
-	});
-
-	const cameraBindGroup = device.createBindGroup({
-		layout: rainRenderPipeline.getBindGroupLayout(3),
-		entries: [
 			{
-				binding: 0,
+				binding: 5,
 				resource: {
 					buffer: cameraBuffer,
 				},
@@ -201,16 +185,12 @@ export default async (canvas, config) => {
 		],
 	});
 
-	const rainRenderPipelineBindGroups = [configBindGroup, msdfBindGroup, timeBindGroup, cameraBindGroup];
-
 	const bundleEncoder = device.createRenderBundleEncoder({
 		colorFormats: [presentationFormat],
 	});
 
 	bundleEncoder.setPipeline(rainRenderPipeline);
-	rainRenderPipelineBindGroups.forEach((bindGroup, index) => {
-		bundleEncoder.setBindGroup(index, bindGroup);
-	});
+	bundleEncoder.setBindGroup(0, bindGroup);
 	const numQuads = numColumns * numRows;
 	bundleEncoder.draw(NUM_VERTICES_PER_QUAD * numQuads, 1, 0, 0);
 	const renderBundles = [bundleEncoder.finish()];
diff --git a/shaders/rainRenderPass.wgsl b/shaders/rainRenderPass.wgsl
index 04e2d5e..d10a636 100644
--- a/shaders/rainRenderPass.wgsl
+++ b/shaders/rainRenderPass.wgsl
@@ -11,20 +11,20 @@ let TWO_PI:f32 = 6.28318530718; // No, I'm not using Tau.
 [[block]] struct MSDFUniforms {
 	numColumns: i32;
 };
-[[group(1), binding(0)]] var<uniform> msdfUniforms:MSDFUniforms;
-[[group(1), binding(1)]] var msdfSampler: sampler;
-[[group(1), binding(2)]] var msdfTexture: texture_2d<f32>;
+[[group(0), binding(1)]] var<uniform> msdfUniforms:MSDFUniforms;
+[[group(0), binding(2)]] var msdfSampler: sampler;
+[[group(0), binding(3)]] var msdfTexture: texture_2d<f32>;
 
 [[block]] struct TimeUniforms {
 	now: i32;
 	frame: i32;
 };
-[[group(2), binding(0)]] var<uniform> timeUniforms:TimeUniforms;
+[[group(0), binding(4)]] var<uniform> timeUniforms:TimeUniforms;
 
 [[block]] struct CameraUniforms {
 	screenSize: vec2<f32>;
 };
-[[group(3), binding(0)]] var<uniform> cameraUniforms:CameraUniforms;
+[[group(0), binding(5)]] var<uniform> cameraUniforms:CameraUniforms;
 
 // Vertex shader
 
diff --git a/webgpu_notes.txt b/webgpu_notes.txt
index ebe43f7..f03b14e 100644
--- a/webgpu_notes.txt
+++ b/webgpu_notes.txt
@@ -40,3 +40,5 @@ Textures were never resizable, you simply forgot
 
 Bind groups let you bind a bunch of resources at once
 Render bundles let you reissue commands
+
+You can only use up to FOUR bind groups on your laptop's device!
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