change dir stucture

public/Camera.js

@@ -0,0 +1,121 @@
+export default class Camera {
+  constructor() {
+    this.x = 0
+    this.y = 0
+
+    this.zoom = 1
+    this.minZoom = .1
+    this.maxZoom = 6
+    this.zoomStep = .05
+  }
+
+  move(x, y) {
+    this.x += x / this.zoom
+    this.y += y / this.zoom
+  }
+
+  setZoom(newzoom, viewportCoordCenter) {
+    const zoom = Math.min(Math.max(newzoom, this.minZoom), this.maxZoom)
+    if (zoom == this.zoom) {
+      return false
+    }
+
+    const zoomFactor = 1 - (this.zoom / zoom)
+    this.move(
+      -viewportCoordCenter.x * zoomFactor,
+      -viewportCoordCenter.y * zoomFactor,
+    )
+    this.zoom = zoom
+    return true
+  }
+
+  zoomOut(viewportCoordCenter) {
+    return this.setZoom(
+      this.zoom - this.zoomStep * this.zoom,
+      viewportCoordCenter
+    )
+  }
+
+  zoomIn(viewportCoordCenter) {
+    return this.setZoom(
+      this.zoom + this.zoomStep * this.zoom,
+      viewportCoordCenter
+    )
+  }
+
+  /**
+   * Translate a coordinate in the viewport to a
+   * coordinate in the world, rounded
+   * @param {x, y} viewportCoord
+   */
+  viewportToWorld(viewportCoord) {
+    const worldCoord = this.viewportToWorldRaw(viewportCoord)
+    return {
+      x: Math.round(worldCoord.x),
+      y: Math.round(worldCoord.y),
+    }
+  }
+
+  /**
+   * Translate a coordinate in the viewport to a
+   * coordinate in the world, not rounded
+   * @param {x, y} viewportCoord
+   */
+  viewportToWorldRaw(viewportCoord) {
+    return {
+      x: (viewportCoord.x / this.zoom) - this.x,
+      y: (viewportCoord.y / this.zoom) - this.y,
+    }
+  }
+
+  /**
+   * Translate a coordinate in the world to a
+   * coordinate in the viewport, rounded
+   * @param {x, y} worldCoord
+   */
+  worldToViewport(worldCoord) {
+    const viewportCoord = this.worldToViewportRaw(worldCoord)
+    return {
+      x: Math.round(viewportCoord.x),
+      y: Math.round(viewportCoord.y),
+    }
+  }
+
+  /**
+   * Translate a coordinate in the world to a
+   * coordinate in the viewport, not rounded
+   * @param {x, y} worldCoord
+   */
+  worldToViewportRaw(worldCoord) {
+    return {
+      x: (worldCoord.x + this.x) * this.zoom,
+      y: (worldCoord.y + this.y) * this.zoom,
+    }
+  }
+
+  /**
+   * Translate a 2d dimension (width/height) in the world to
+   * one in the viewport, rounded
+   * @param {w, h} worldDim
+   */
+  worldDimToViewport(worldDim) {
+    const viewportDim = this.worldDimToViewportRaw(worldDim)
+    return {
+      w: Math.round(viewportDim.w),
+      h: Math.round(viewportDim.h),
+    }
+  }
+
+
+  /**
+   * Translate a 2d dimension (width/height) in the world to
+   * one in the viewport, not rounded
+   * @param {w, h} worldDim
+   */
+  worldDimToViewportRaw(worldDim) {
+    return {
+      w: worldDim.w * this.zoom,
+      h: worldDim.h * this.zoom,
+    }
+  }
+}