dirty initial commit

game/Camera.js

@@ -0,0 +1,77 @@
+import BoundingRectangle from "./BoundingRectangle.js"
+
+export default class Camera {
+    constructor(canvas) {
+        this.x = 0
+        this.y = 0
+        
+        // TODO: when canvas resizes, this should 
+        //       syncronize with the cam
+        this.width = canvas.width
+        this.height = canvas.height
+
+        this.zoom = 1
+        this.minZoom = .2
+        this.maxZoom = 6
+        this.zoomStep = .05
+    }
+
+    rect() {
+        // when no zoom is relevant:
+        return new BoundingRectangle(
+            this.x,
+            this.x + this.width - 1,
+            this.y,
+            this.y + this.height - 1
+        )
+
+        // when zoom is relevant:
+        // TODO: check if still true
+        const w_final = this.width * this.zoom
+        const h_final = this.height * this.zoom
+        return new BoundingRectangle(
+            this.x + (this.width - w_final) / 2,
+            this.x + (this.width + w_final) / 2,
+            this.y + (this.height - h_final) / 2,
+            this.y + (this.height + h_final) / 2
+        )
+    }
+    
+    move(x, y) {
+        this.x += x / this.zoom
+        this.y += y / this.zoom
+    }
+
+    zoomOut() {
+        const newzoom = Math.max(this.zoom - this.zoomStep, this.minZoom)
+        if (newzoom !== this.zoom) {
+            // centered zoom
+            this.x -= ((this.width / this.zoom) - (this.width / newzoom)) / 2
+            this.y -= ((this.height / this.zoom) - (this.height / newzoom)) / 2
+
+            this.zoom = newzoom
+            return true
+        }
+        return false
+    }
+
+    zoomIn() {
+        const newzoom = Math.min(this.zoom + this.zoomStep, this.maxZoom)
+        if (newzoom !== this.zoom) {
+            // centered zoom
+            this.x -= ((this.width / this.zoom) - (this.width / newzoom)) / 2
+            this.y -= ((this.height / this.zoom) - (this.height / newzoom)) / 2
+
+            this.zoom = newzoom
+            return true
+        }
+        return false
+    }
+
+    translateMouse(mouse) {
+        return {
+            x: (mouse.x / this.zoom) - this.x,
+            y: (mouse.y / this.zoom) - this.y,
+        }
+    }
+}