view: add simple input handlers

2 files changed, 75 insertions, 0 deletions

diff --git a/src/view/input/DirectionHandler.ts b/src/view/input/DirectionHandler.ts
new file mode 100644
index 0000000..691ba01
--- /dev/null
+++ b/src/view/input/DirectionHandler.ts
@@ -0,0 +1,36 @@
+import {Listenable} from '../../util';
+import InputHandler from './InputHandler';
+
+import {vec2} from 'gl-matrix';
+
+export const enum Keycode {
+	Left = 37,
+	Up = 38,
+	Right = 39,
+	Down = 40,
+}
+
+export default class DirectionHandler extends Listenable<[vec2]> {
+	private readonly input: InputHandler;
+
+	constructor() {
+		super();
+
+		this.input = new InputHandler(new Set([Keycode.Left, Keycode.Up, Keycode.Right, Keycode.Down]));
+
+		this.input.addListener(() => {
+			const dir = vec2.create();
+
+			if (this.input.has(Keycode.Left))
+				vec2.add(dir, dir, [-1, 0]);
+			if (this.input.has(Keycode.Up))
+				vec2.add(dir, dir, [0, -1]);
+			if (this.input.has(Keycode.Right))
+				vec2.add(dir, dir, [1, 0]);
+			if (this.input.has(Keycode.Down))
+				vec2.add(dir, dir, [0, 1]);
+
+			this.runListeners(dir);
+		});
+	}
+}
diff --git a/src/view/input/InputHandler.ts b/src/view/input/InputHandler.ts
new file mode 100644
index 0000000..a6f1293
--- /dev/null
+++ b/src/view/input/InputHandler.ts
@@ -0,0 +1,39 @@
+import {Listenable} from '../../util';
+
+export default class InputHandler extends Listenable<[]> {
+	private readonly keys: Set<number> = new Set();
+
+	constructor(relevantKeys: Set<number>) {
+		super();
+
+		window.addEventListener('keydown', (ev) => {
+			if (!relevantKeys.has(ev.keyCode))
+				return;
+
+			ev.preventDefault();
+
+			if (this.keys.has(ev.keyCode))
+				return;
+
+			this.keys.add(ev.keyCode);
+			this.runListeners();
+		});
+
+		window.addEventListener('keyup', (ev) => {
+			if (!relevantKeys.has(ev.keyCode))
+				return;
+
+			ev.preventDefault();
+
+			if (!this.keys.has(ev.keyCode))
+				return;
+
+			this.keys.delete(ev.keyCode);
+			this.runListeners();
+		});
+	}
+
+	public has(key: number): boolean {
+		return this.keys.has(key);
+	}
+}