87 lines
2.1 KiB
JavaScript
87 lines
2.1 KiB
JavaScript
export default class Camera {
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constructor(canvas) {
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this.x = 0
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this.y = 0
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// TODO: when canvas resizes, this should
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// syncronize with the cam
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this.width = canvas.width
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this.height = canvas.height
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this.zoom = 1
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this.minZoom = .2
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this.maxZoom = 6
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this.zoomStep = .05
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}
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rect() {
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return {
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x: -this.x,
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y: -this.y,
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w: this.width / this.zoom,
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h: this.height / this.zoom,
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}
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}
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move(x, y) {
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this.x += x / this.zoom
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this.y += y / this.zoom
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}
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zoomOut() {
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const newzoom = Math.max(this.zoom - this.zoomStep, this.minZoom)
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if (newzoom !== this.zoom) {
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// centered zoom
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this.x -= ((this.width / this.zoom) - (this.width / newzoom)) / 2
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this.y -= ((this.height / this.zoom) - (this.height / newzoom)) / 2
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this.zoom = newzoom
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return true
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}
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return false
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}
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zoomIn() {
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const newzoom = Math.min(this.zoom + this.zoomStep, this.maxZoom)
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if (newzoom !== this.zoom) {
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// centered zoom
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this.x -= ((this.width / this.zoom) - (this.width / newzoom)) / 2
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this.y -= ((this.height / this.zoom) - (this.height / newzoom)) / 2
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this.zoom = newzoom
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return true
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}
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return false
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}
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/**
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* Translate a coordinate in the viewport to a
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* coordinate in the world
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* @param {x, y} coord
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*/
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viewportToWorld(coord) {
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return {
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x: (coord.x / this.zoom) - this.x,
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y: (coord.y / this.zoom) - this.y,
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}
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}
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/**
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* Translate a coordinate in the world to a
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* coordinate in the viewport
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* @param {x, y} coord
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*/
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worldToViewport(coord) {
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return {
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x: (coord.x + this.x) * this.zoom,
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y: (coord.y + this.y) * this.zoom,
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}
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}
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worldDimToViewport(dim) {
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return {
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w: dim.w * this.zoom,
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h: dim.h * this.zoom,
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}
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}
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}
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