Move flow-fields code here

2023-10-23 02:16:06 -07:00 · 2023-10-23 02:16:06 -07:00 · ef2f98ce53
commit ef2f98ce53
parent df621db3a2
5 changed files with 141 additions and 0 deletions
--- a/README.md
+++ b/README.md
@ -11,3 +11,18 @@ Or build with:
 ```
 $ pnpm run build
 ```
+
+# Individual Projects
+
+## Flow Fields
+
+Inspired by https://youtu.be/M_SUcX66SDA Low Byte Productions Flow Fields video
+
+Uses code from:
+* https://github.com/francisrstokes/vec-la-fp/tree/master
+* https://github.com/francisrstokes/microcan
+
+
+## Konva-ball
+
+Experimenting with konva library
--- a/src/flow-fields/index.html
+++ b/src/flow-fields/index.html
@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<html>
+    <head>
+        <meta charset="utf-8">
+        <meta name="viewport" content="width=device-width, initial-scale=1.0">
+        <title>Flow Fields</title>
+        <script type="module" src="index.js"></script>
+    </head>
+
+    <body>
+        <canvas id="main"></canvas>
+    </body>
+</html>
--- a/src/flow-fields/index.js
+++ b/src/flow-fields/index.js
@ -0,0 +1,104 @@
+// Inspired by https://youtu.be/M_SUcX66SDA Low Byte Productions Flow Fields video
+
+import { vScale, vAdd, vAngle } from "./util.js";
+
+//const vAngle = (a) => [Math.cos(a), Math.sin(a)];
+
+const canvas = document.getElementById("main");
+const ctx = canvas.getContext("2d");
+
+const width = 800;
+const height = 800;
+
+// A 10x10 grid, transformed onto the canvas
+const n = 25;
+const fieldSize = width/n;
+
+canvas.setAttribute("width", width);
+canvas.setAttribute("height", height);
+
+
+
+const fill = (ctx, r = 0, g = 0, b = 0, a = 255) => {
+    ctx.fillStyle = `rgba(${r}, ${g}, ${b}, ${a})`;
+}
+
+const stroke =  (ctx, r = 0, g = 0, b = 0, a = 255) => {
+    ctx.strokeStyle = `rgba(${r}, ${g}, ${b}, ${a})`;
+};
+
+const line = (ctx, v, v2) => {
+  ctx.beginPath();
+  ctx.moveTo(...v);
+  ctx.lineTo(...v2);
+  ctx.stroke();
+  ctx.closePath();
+}
+
+const ellipse = (ctx, v, rx, ry = rx, oa = 0, sa = 0, ea = Math.PI * 2) => {
+  ctx.beginPath();
+  ctx.ellipse(...v, rx, ry, oa, sa, ea, false);
+  ctx.stroke();
+  ctx.fill();
+  ctx.closePath();
+}
+
+const background = (ctx, r = 0, g = 0, b = 0, a = 255) => {
+    fill(ctx, r, g, b, a);
+    ctx.fillRect(0, 0, width, height);
+}
+
+fill(ctx, 0,0,0,0);
+stroke(ctx, 255,255,255,1);
+background(ctx, 0, 0, 255, width, height);
+
+const vRandom = () => vAngle(Math.random() * Math.PI * 2);
+
+
+
+/*
+for (let y = 0; y < n; y++) {
+    for (let x = 0; x < n; x++) {
+        const sv = vAdd([fieldSize/2, fieldSize/2], vScale(fieldSize, [x, y]));
+        ellipse(ctx, sv, fieldSize/2);
+    }
+}
+*/
+
+let prevTimestamp;
+
+const draw = (timestamp) => {
+
+    if (prevTimestamp === undefined) {
+        prevTimestamp = timestamp;
+    }
+
+    const elapsed = timestamp - prevTimestamp;
+
+    if (elapsed > 500) {
+        prevTimestamp = timestamp;
+
+        const field = Array.from({length: n}, () => Array.from({length: n}, () => {
+            return vRandom();
+        }));
+
+        fill(ctx, 0,0,0,0);
+        stroke(ctx, 255,255,255,1);
+        background(ctx, 0, 0, 255, width, height);
+
+        field.forEach((row, y) => row.forEach((fv, x) => {
+            const sv = vAdd([fieldSize/2, fieldSize/2], vScale(fieldSize, [x, y]));
+            const upper = vAdd(sv, vScale(fieldSize/2, fv));
+            const lower = vAdd(sv, vScale(-fieldSize/2, fv));
+            line(ctx, upper, lower);
+            fill(ctx, 255,255,255,1);
+            ellipse(ctx, upper, 2);
+
+        }));
+    }
+
+
+    window.requestAnimationFrame(draw);
+};
+
+draw();
--- a/src/flow-fields/util.js
+++ b/src/flow-fields/util.js
@ -0,0 +1,8 @@
+
+const vScale = (scale, vec) => vec.map(n => n * scale);
+
+const vAdd = (v0, v1) => [v0[0] + v1[0], v0[1] + v1[1]];
+
+const vAngle = (a) => [Math.cos(a), Math.sin(a)];
+
+export { vAdd, vScale, vAngle };
--- a/src/index.html
+++ b/src/index.html
@ -8,6 +8,7 @@
        <h1>Spazer</h1>
        <ul>
            <li> <a href="./konva-ball/index.html">Konva-ball</a>
+            <li> <a href="./flow-fields/index.html">Flow-fields</a>
        </ul>
    </body>
 </html>