controller: gamecontext: implement simple collision handling

src/controller/gamecontext.ts

@@ -6,6 +6,7 @@ import { loadMap } from '../view/map';
 import { Renderer } from '../view/renderer/renderer';
 import { SpriteView } from '../view/sprite';
 
+import { LineSegment } from '../math/line';
 import { getJSON } from '../util';
 
 import { vec2 } from 'gl-matrix';
@@ -35,9 +36,16 @@ export class GameContext {
 
 	private readonly input: DirectionHandler;
 
-	private readonly entityPos: vec2 = vec2.create();
+	private readonly entityPos: vec2 = vec2.clone([6, 6]);
 	private readonly entityMovement: vec2 = vec2.create();
 
+	private readonly walls: LineSegment[] = [
+		new LineSegment(vec2.fromValues(1, 1), vec2.fromValues(1, 0), 10),
+		new LineSegment(vec2.fromValues(11, 1), vec2.fromValues(0, 1), 10),
+		new LineSegment(vec2.fromValues(11, 11), vec2.fromValues(-1, 0), 10),
+		new LineSegment(vec2.fromValues(1, 11), vec2.fromValues(0, -1), 10),
+	];
+
 	private constructor(
 		private readonly renderer: Renderer,
 		private readonly mapView: SpriteView,
@@ -62,7 +70,34 @@ export class GameContext {
 	}
 
 	private updateStep(): void {
-		vec2.scaleAndAdd(this.entityPos, this.entityPos, this.entityMovement, this.speed);
+		let move = new LineSegment(this.entityPos, this.entityMovement, this.speed);
+		const p = vec2.create();
+
+		let rescan = true;
+
+		while (rescan) {
+			rescan = false;
+
+			for (const w of this.walls) {
+				if (!w.collidesMove(move))
+					continue;
+
+				move.getP2(p);
+				w.projectPoint(p, p);
+
+				const move2 = LineSegment.fromPoints(this.entityPos, p);
+				if (move2.l === 0)
+					return;
+
+				if (!move.equals(move2)) {
+					move = move2;
+					rescan = true;
+					break;
+				}
+			}
+		}
+
+		move.getP2(this.entityPos);
 	}
 
 	private update(time: number): void {