Starfield: More color options

src/starfield/starfield.ts

@@ -1,4 +1,5 @@
 import { reference } from "./reference.ts"
+import * as dat from "dat.gui";
 
 const canvas = document.querySelector("#mainCanvas");
 const ctx = canvas.getContext("2d");
@@ -10,6 +11,10 @@ canvas.width = cw * dpr;
 canvas.height = ch * dpr;
 ctx.scale(dpr, dpr);
 
+function random(min, max) {
+    return min + Math.random() * ( max - min );
+}
+
 function resize() {
     canvas.width  = window.innerWidth * dpr;
     canvas.height = window.innerHeight * dpr;
@@ -24,6 +29,7 @@ class Star {
     this.x = x;
     this.y = y;
     this.multiplier = multiplier;
+    this.color = random(0, 360);
   }
 
   canvasPos() {
@@ -40,15 +46,28 @@ class Star {
     return 1.0;
   }
 
-  render(ctx) {
+  render(ctx, style) {
     const { x, y } = this.canvasPos();
     const r = this.size();
-    ctx.fillStyle = "red";
+    ctx.fillStyle = this.computeStyle(style);
     ctx.beginPath();
     ctx.arc(x, y, r, 0, 2*Math.PI)
     ctx.fill();
   }
 
+  private computeStyle(style) {
+    if (style == "white") {
+      return "white";
+    } 
+
+    if (style == "red") {
+      return "red";
+    }
+    if (style == "multi") {
+      return `hsl(${this.color}, 100%, 50%)`;
+    }
+  }
+
   static make() {
     const angle = Math.random() * 2*Math.PI
     const x = Math.cos(angle);
@@ -67,12 +86,17 @@ const state = {
   timeSinceLastStar: Infinity,
 };
 
-let start = null;
-let stars = [];
-let timeSinceLastStar = Infinity;
 
-const starIntervalms = 2000;
-const fadeout = 8 / 100;
+const options = {
+  fadeout: 8/100,
+  starIntervalMS: 2000,
+  starStyle: "white",
+}
+
+const controls = new dat.GUI({name: "Controls", closed: false});
+controls.add(options, "fadeout").min(0).max(1).step(0.01).name("Fadeout");
+controls.add(options, "starIntervalMS").min(500).max(50000).step(500).name("Star Interval");
+controls.add(options, "starStyle").options({"White": "white", "Red":"red", "Multi": "multi"}).name("Style");
 
 function clear(ctx, alpha) {
   ctx.globalCompositeOperation = "destination-out";
@@ -90,14 +114,14 @@ function loop(timestamp) {
   // Create a new star if it's been long enough since
   // the previous one
   state.timeSinceLastStar += progress;
-  if (state.timeSinceLastStar > starIntervalms) {
+  if (state.timeSinceLastStar > options.starIntervalMS) {
     state.timeSinceLastStar = 0
     state.stars.push(Star.make());
   }
 
   // Clear the screen.
   // If you want the hyperspace effect, skip this.
-  clear(ctx, fadeout);
+  clear(ctx, options.fadeout);
 
   state.stars.forEach((star) => {
     // Increase the star's distance from the middle
@@ -105,7 +129,7 @@ function loop(timestamp) {
     const multiplier = star.multiplier;
     star.x *= multiplier
     star.y *= multiplier
-    star.render(ctx);
+    star.render(ctx, options.starStyle);
   })
 
   // Remove stars outside the view boundary