Attempt to generalize

blog/2024-11-15-playing-with-fire/1-introduction/Gasket.jsx

@@ -9,6 +9,7 @@ const functions = [
 ]
 
 function chaosGame(image) {
+    var plotter = new Plotter(image.width, image.height);
     var [x, y] = [randomBiUnit(), randomBiUnit()];
 
     for (var count = 0; count < iterations; count++) {
@@ -16,9 +17,11 @@ function chaosGame(image) {
         [x, y] = functions[i](x, y);
 
         if (count > 20) {
-            plot(x, y, image);
+            plotter.plot(x, y);
-        }
         }
     }
 
+    plotter.paint(image);
+}
+
 render(<Canvas renderFn={chaosGame}/>)

blog/2024-11-15-playing-with-fire/1-introduction/biunit.ts

@@ -1,3 +0,0 @@
-export default function randomBiUnit() {
-    return Math.random() * 2 - 1;
-}

blog/2024-11-15-playing-with-fire/1-introduction/index.mdx

@@ -157,15 +157,15 @@ Let's turn this into code, one piece at a time.
 
 First, the "bi-unit square" is the range $[-1, 1]$. We can pick a random point like this:
 
-import biunitSource from '!!raw-loader!./biunit'
+import randomBiunitSource from '!!raw-loader!../src/randomBiunit'
 
-<CodeBlock language="typescript">{biunitSource}</CodeBlock>
+<CodeBlock language="typescript">{randomBiunitSource}</CodeBlock>
 
 Next, we need to choose a random integer from $0$ to $n - 1$:
 
-import randintSource from '!!raw-loader!./randint'
+import randomIntegerSource from '!!raw-loader!../src/randomInteger'
 
-<CodeBlock language="typescript">{randintSource}</CodeBlock>
+<CodeBlock language="typescript">{randomIntegerSource}</CodeBlock>
 
 Finally, implementing the `plot` function. Web browsers have a [Canvas API](https://developer.mozilla.org/en-US/docs/Web/API/Canvas_API)
 we can use for 2D graphics. In our case, the plot function will take an $(x,y)$ coordinate and plot it by

blog/2024-11-15-playing-with-fire/1-introduction/plot.ts

@@ -1,32 +1,40 @@
-export default function plot(x: number, y: number, image: ImageData) {
+export function imageIndex(x: number, y: number, width: number, stride: number): number {
+    return y * (width * stride) + x * 4;
+}
+
+export class Plotter {
+    private readonly pixels: Array<boolean>;
+
+    constructor(private readonly width: number, private readonly height: number) {
+        this.pixels = new Array(width * height).fill(false);
+    }
+
+    public plot(x: number, y: number) {
         // Translate (x,y) coordinates to pixel coordinates.
         // The display range we care about is x=[0, 1], y=[0, 1],
         // so our pixelX and pixelY coordinates are easy to calculate:
-    const pixelX = Math.floor(x * image.width);
+        const pixelX = Math.floor(x * this.width);
-    const pixelY = Math.floor(y * image.height);
+        const pixelY = Math.floor(y * this.height);
 
-    // If we have an (x,y) coordinate outside the display range,
+        // Translate the pixel coordinates into an index
-    // skip it
+        const pixelIndex = imageIndex(pixelX, pixelY, this.width, 1);
-    if (
+
-        pixelX < 0 ||
+        // If the index is valid, enable that pixel
-        pixelX > image.width ||
+        if (0 <= pixelIndex && pixelIndex < this.pixels.length) {
-        pixelY < 0 ||
+            this.pixels[pixelIndex] = true;
-        pixelY > image.height
+        }
-    ) {
-        return;
     }
 
-    // ImageData is an array that contains four bytes per pixel
+    public paint(image: ImageData) {
-    // (one for each of the red, green, blue, and alpha values).
+        // "Paint" all our pixels by setting their value to black
-    // The (pixelX, pixelY) coordinates are used to find where
+        for (var pixelIndex = 0; pixelIndex < this.pixels.length; pixelIndex++) {
-    // in the image we need to write.
+            if (this.pixels[pixelIndex]) {
-    const index = pixelY * (image.width * 4) + pixelX * 4;
+                const imageIndex = pixelIndex * 4;
-
+                image.data[imageIndex] = 0; // red
-    // Set the pixel to black by writing a 0 to the first three
+                image.data[imageIndex + 1] = 0; // green
-    // bytes (red, green, blue), and 256 to the last byte (alpha),
+                image.data[imageIndex + 2] = 0; // blue
-    // starting at our index:
+                image.data[imageIndex + 3] = 0xff; // alpha
-    image.data[index] = 0;
+            }
-    image.data[index + 1] = 0;
+        }
-    image.data[index + 2] = 0;
+    }
-    image.data[index + 3] = 0xff;
 }

blog/2024-11-15-playing-with-fire/1-introduction/randint.ts

@@ -1,3 +0,0 @@
-export default function randomInteger(min: number, max: number) {
-    return Math.floor(Math.random() * (max - min)) + min;
-}

blog/2024-11-15-playing-with-fire/1-introduction/scope.ts

@@ -1,13 +1,13 @@
 import React from 'react';
 
-import randomBiUnit from './biunit';
+import { randomBiUnit } from '../src/randomBiunit';
-import plot from './plot';
+import { Plotter } from './plot';
-import randomInteger from './randint';
+import { randomInteger } from '../src/randomInteger';
 import Canvas from './Canvas';
 
 const Scope = {
     React,
-    plot,
+    Plotter,
     randomBiUnit,
     randomInteger,
     Canvas

blog/2024-11-15-playing-with-fire/src/FlameCanvas.tsx

@@ -0,0 +1,99 @@
+import {createContext, useEffect, useRef, useState} from "react";
+import {Transform} from "./transform";
+import {randomBiUnit} from "./randomBiunit";
+import {useColorMode} from "@docusaurus/theme-common";
+import {randomChoice} from "./randomChoice";
+
+export interface Flame {
+    transforms: [number, Transform][];
+    final: Transform;
+    palette: Uint8Array;
+}
+
+interface IFlameContext {
+    setQuality?: (quality: number) => void;
+    setFlame?: (flame: Flame) => void;
+}
+
+export const FlameContext = createContext<IFlameContext>({});
+
+abstract class Renderer {
+    protected readonly _size: number;
+    protected _x: number = randomBiUnit();
+    protected _y: number = randomBiUnit();
+    protected _iterations: number = 0;
+
+    protected _flame?: Flame;
+
+    protected constructor(size: number) {
+        this._size = size;
+    }
+
+    abstract plot(x: number, y: number, c: number): void;
+    abstract run(iterations: number): void;
+    abstract paint(image: ImageData): void;
+
+    public get size(): number {
+        return this._size;
+    }
+
+    public get iterations(): number {
+        return this._iterations;
+    }
+
+    public set flame(value: Flame) {
+        [this._x, this._y] = [randomBiUnit(), randomBiUnit()];
+        this._iterations = 0;
+    }
+}
+
+export interface Props {
+    renderer: Renderer;
+    children?: React.ReactNode;
+}
+
+export const FlameCanvas: React.FC<Props> = ({renderer, children}) => {
+    const ITER_STEP = 10000;
+    const canvasRef = useRef<HTMLCanvasElement | null>(null);
+
+    const colorMode = useColorMode();
+    const [quality, setQuality] = useState<number>();
+    const [flame, setFlame] = useState<Flame>(null);
+
+    var image: ImageData = null;
+
+    function animate() {
+        renderer.run(ITER_STEP);
+        paint();
+
+        if (renderer.iterations < quality * renderer.size * renderer.size) {
+            requestAnimationFrame(this);
+        }
+    }
+
+    function paint() {
+
+    }
+
+    useEffect(() => {
+        renderer.flame = flame;
+        requestAnimationFrame(animate);
+    }, [quality, flame]);
+
+    useEffect(() => { paint(); }, [colorMode]);
+
+    return (
+        <FlameContext.Provider value={{setFlame, setQuality}}>
+            <canvas
+                ref={canvasRef}
+                width={renderer.size}
+                height={renderer.size}
+                style={{
+                    aspectRatio: '1 / 1',
+                    width: '100%',
+                }}
+            />
+            {children}
+        </FlameContext.Provider>
+    )
+}

blog/2024-11-15-playing-with-fire/src/randomBiunit.ts

@@ -0,0 +1,3 @@
+export function randomBiUnit() {
+    return Math.random() * 2 - 1;
+}

blog/2024-11-15-playing-with-fire/src/randomChoice.ts

@@ -0,0 +1,22 @@
+/**
+ * @param choices array of [weight, value] pairs
+ * @returns pair of [index, value]
+ */
+export function randomChoice<T>(choices: [number, T][]): [number, T] {
+    const weightSum = choices.reduce(
+        (current, [weight, _]) => current + weight,
+        0
+    );
+    var choice = Math.random() * weightSum;
+
+    for (var i = 0; i < choices.length; i++) {
+        const [weight, t] = choices[i];
+        if (choice < weight) {
+            return [i, t];
+        }
+
+        choice -= weight;
+    }
+
+    throw "unreachable";
+}

blog/2024-11-15-playing-with-fire/src/randomInteger.ts

@@ -0,0 +1,3 @@
+export function randomInteger(min: number, max: number) {
+    return Math.floor(Math.random() * (max - min)) + min;
+}

blog/2024-11-15-playing-with-fire/src/transform.ts

@@ -4,6 +4,7 @@ import { Variation } from './variations'
 export interface Transform {
     coefs: Coefs,
     variations: [number, Variation][],
-    coefsPost: Coefs,
+    enabled: boolean,
-    color: number
+    coefsPost?: Coefs,
+    color?: number
 }