README update

gksander · Jul 27, 2022 · 48adbbd · 48adbbd · vercel · Jul 27, 2022
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diff --git a/README.md b/README.md
@@ -1,38 +1,43 @@
-# create-svelte
+# Mandelbruh
 
-Everything you need to build a Svelte project, powered by [`create-svelte`](https://github.com/sveltejs/kit/tree/master/packages/create-svelte).
+This repo houses the code for [mandelbruh](https://mandelbruh.dev), a Mandelbrot set visualizer built using WebGL and Svelte.
 
-## Creating a project
+![Image of the site](./docs/sample.png)
 
-If you're seeing this, you've probably already done this step. Congrats!
+The UI allows you to adjust the number of "iterations" used to determine if a point "escapes". You can also adjust the colors for the visualization Furthermore, you can scroll to zoom, and click-and-drag to pan the view.
 
-```bash
-# create a new project in the current directory
-npm init svelte
+## How does it work?
 
-# create a new project in my-app
-npm init svelte my-app
-```
-
-## Developing
+The visualization is powered by WebGL (mostly just shaders), and the UI is powered by Svelte. At a high-level, this is how things work:
 
-Once you've created a project and installed dependencies with `npm install` (or `pnpm install` or `yarn`), start a development server:
+- The UI is powered by Svelte, using Svelte stores etc. to manage input values. For example, there's an `iterations` value that can be adjusted in the UI – the value for this is stored in a Svelte store, but is essentially just an integer value.
+- There is a WebGL program running inside of a canvas element. The WebGL program render cycle is running on a `requestAnimationFrame` loop, and uses various JS variables/store values that get passed along to WebGL as "uniform values".
+- As JS variables/store values are updated, the next animation frame will pick up the value and pass it along to the WebGL context to be used in the next render.
 
-```bash
-npm run dev
+The code for these WebGL shaders can be found in [`src/shaders`](./src/shaders/).In [the `fs.frag`](./src/shaders/fs.frag) file, you'll notice some declarations like:
 
-# or start the server and open the app in a new browser tab
-npm run dev -- --open
+```glsl
+uniform int iterations;
+uniform vec2 center;
+uniform float scale;
+uniform float resolution;
+uniform vec3 boundColor;
+uniform vec3 transitionColor;
+uniform vec3 escapeColor;
 ```
 
-## Building
+which are essentially the input variables to the shader process, whose values are provided from the JS side of things.
 
-To create a production version of your app:
+In [the `FractalDisplay.svelte` file](./src/components/FractalDisplay.svelte) you'll see something like this:
 
-```bash
-npm run build
+```ts
+gl.uniform1f(locations.resolution, width);
+gl.uniform1i(locations.iterations, Math.round($iterations));
+gl.uniform1f(locations.scale, $scale);
+gl.uniform2f(locations.center, $center.x + centerDelta.x, $center.y + centerDelta.y);
+gl.uniform3f(locations.boundColor, ...$boundColor);
+gl.uniform3f(locations.transitionColor, ...$transitionColor);
+gl.uniform3f(locations.escapeColor, ...$escapeColor);
 ```
 
-You can preview the production build with `npm run preview`.
-
-> To deploy your app, you may need to install an [adapter](https://kit.svelte.dev/docs/adapters) for your target environment.
+These `gl.uniform1f` etc calls are what send our JS values into the WebGL context for our shader to use.
diff --git a/docs/sample.png b/docs/sample.png
diff --git a/src/components/FractalDisplay.svelte b/src/components/FractalDisplay.svelte
@@ -31,9 +31,10 @@
 		escapeColor: null as WebGLUniformLocation | null
 	};
 
-	// Options for rendering
-
+	// Some local interaction state
 	let centerDelta = { x: 0, y: 0 };
+	let isResizing = false;
+	let resizeTimeout;
 
 	// Interactions
 	let mouseDownStartPos = null as { x: number; y: number; ts: number } | null;
@@ -139,8 +140,10 @@
 	};
 
 	const animate = () => {
-		measure();
-		render();
+		if (!isResizing) {
+			measure();
+			render();
+		}
 		requestAnimationFrame(animate);
 	};
 
@@ -210,3 +213,14 @@
 		on:wheel|preventDefault|stopPropagation={handleWheel}
 	/>
 </div>
+
+<!-- Throttle the RAF rendering when resizing window -->
+<svelte:window
+	on:resize={() => {
+		isResizing = true;
+		clearTimeout(resizeTimeout);
+		resizeTimeout = setTimeout(() => {
+			isResizing = false;
+		}, 150);
+	}}
+/>
diff --git a/src/shaders/fs.frag b/src/shaders/fs.frag
@@ -2,7 +2,6 @@ uniform int iterations;
 uniform vec2 center;
 uniform float scale;
 uniform float resolution;
-
 uniform vec3 boundColor;
 uniform vec3 transitionColor;
 uniform vec3 escapeColor;