From 910d29e175f71ef34931bd754ab2293728073696 Mon Sep 17 00:00:00 2001
From: Rezmason <jeremysachs@rezmason.net>
Date: Thu, 11 Nov 2021 23:30:37 -0800
Subject: [PATCH] Poking gpu-buffer a bit because I'm apparently afraid of
 writing a blur shader which I've already written once.

---
 TODO.txt          | 16 ++++++++--------
 lib/gpu-buffer.js | 34 ++++++++++++++++------------------
 2 files changed, 24 insertions(+), 26 deletions(-)

diff --git a/TODO.txt b/TODO.txt
index 198b183..cd76198 100644
--- a/TODO.txt
+++ b/TODO.txt
@@ -5,6 +5,14 @@ WebGPU
   Update links in issues
   Get rid of end pass once it's possible to copy a bgra8unorm to a canvas texture
 
+Support looping
+
+Write an explanation of the rain pass (and include images)
+  Compute
+  Volumetric quads
+  Fullscreen quad and spacial mapping
+  MSDFs
+
 gpu-buffer, working title
   Try and use it for the palette color buffer
   Test it
@@ -13,14 +21,6 @@ gpu-buffer, working title
   Capture expected requirements down the road, make roadmap
   License it and put it somewhere else
 
-Write an explanation of the rain pass (and include images)
-  Compute
-  Volumetric quads
-  Fullscreen quad and spacial mapping
-  MSDFs
-
-Support looping
-
 Resurrection
   Modified glyph order?
   New glyphs?
diff --git a/lib/gpu-buffer.js b/lib/gpu-buffer.js
index 657dc69..280dec1 100644
--- a/lib/gpu-buffer.js
+++ b/lib/gpu-buffer.js
@@ -117,14 +117,13 @@ const parseAttributes = (str) => {
 	const attributes = {};
 	for (const attr of str.split(",").filter((attr) => attr.length > 0)) {
 		const match = attr.match(/(\w+)(\((.*)\))?/); // foo(bar)
-		const [_, name, __, value] = match;
-		attributes[name] = value;
+		const [_, identifier, __, value] = match;
+		attributes[identifier] = value;
 	}
 	return attributes;
 };
 
-const parseStruct = (str, structLayouts) => {
-	const [_, block, name, body] = str;
+const parseStructLayout = (identifier, body, isBlock, structLayouts) => {
 	const fields = [];
 	let byteOffset = 0;
 	const lines = body
@@ -132,12 +131,12 @@ const parseStruct = (str, structLayouts) => {
 		.split(";")
 		.filter((s) => s.length > 0);
 	for (const line of lines) {
-		const fieldMatch = line.match(/(\[\[(.*?)\]\])? ?(\w+) ?: (\[\[(.*?)\]\])? ?(.*)/); // [[...]] foo : [[...]] bar;
+		const fieldMatch = line.match(/(\[\[(.*?)\]\])? ?(\w+) ?: ?(\[\[(.*?)\]\])? ?(.*)/); // [[...]] foo : [[...]] bar;
 		const [_, __, leftAttributes, identifier, ___, rightAttributes, type] = fieldMatch;
 
 		const typeData = getTypeData(type, parseAttributes(rightAttributes ?? ""), structLayouts);
 		if (typeData == null) {
-			console.warn(`Skipping layout for struct ${name}.`);
+			console.warn(`gSkipping struct ${identifier}.`);
 			return null;
 		}
 
@@ -155,23 +154,22 @@ const parseStruct = (str, structLayouts) => {
 	const minSizeInBytes = byteOffset;
 	const align = Math.max(...fields.map((field) => field.align));
 	const size = Math.ceil(minSizeInBytes / align) * align;
-	return { name, fields, size, align };
+	return { identifier, isBlock, fields, size, align };
 };
 
 const parseStructLayoutsFromShader = (wgsl) => {
 	wgsl = wgsl
-		.replace(/\/\*(.|\n)*?\*\//gm, "") // remove multi-line comments
 		.replace(/\s*\/\/.*$/gm, "") // remove end-of-line comments
-		.replace(/\n/gm, "") // remove newlines
-		.replace(/:/g, ": ") // add space after colons
-		.replace(/\s+/g, " "); // convert all whitespace to single space character
+		.replace(/\/\*.*?\*\//gms, "") // remove multi-line comments
+		.replace(/\s+/gm, " "); // convert all contiguous whitespace to single space characters
 
 	const structLayouts = {};
-	const structMatches = Array.from(wgsl.matchAll(/(\[\[block\]\])? ?struct (\w+) \{(.*?)\};/g)); // [[block]] struct Foo {...}
-	for (const struct of structMatches) {
-		const layout = parseStruct(struct, structLayouts);
+	const structMatches = Array.from(wgsl.matchAll(/(\[\[block\]\])? ?struct (\w+) ?\{(.*?)\};/g)); // [[block]] struct Foo {...}
+	for (const structMatch of structMatches) {
+		const [_, block, identifier, body] = structMatch;
+		const layout = parseStructLayout(identifier, body, block != null, structLayouts);
 		if (layout != null) {
-			structLayouts[layout.name] = layout;
+			structLayouts[layout.identifier] = layout;
 		}
 	}
 	return structLayouts;
@@ -211,8 +209,8 @@ const makeGenerator = (layout, structLayouts) => {
 			if (destination == null) {
 				let size = layout.size;
 				const lastField = layout.fields[layout.fields.length - 1];
-				if (lastField.isArray && lastField.name in object) {
-					size += lastField.stride * object[lastField.name].length;
+				if (lastField.isArray && lastField.identifier in object) {
+					size += lastField.stride * object[lastField.identifier].length;
 				}
 				destination = new ArrayBuffer(size);
 			}
@@ -240,7 +238,7 @@ const structs = Object.freeze({
 			throw new Error("Input is not a string.");
 		}
 		const structLayouts = parseStructLayoutsFromShader(wgsl);
-		return Object.fromEntries(Object.entries(structLayouts).map(([name, layout]) => [name, makeGenerator(layout, structLayouts)]));
+		return Object.fromEntries(Object.entries(structLayouts).map(([identifier, layout]) => [identifier, makeGenerator(layout, structLayouts)]));
 	},
 });