134 lines
2.9 KiB
JavaScript
134 lines
2.9 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 = .1
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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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setZoom(newzoom, centerCoordViewport) {
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const zoom = Math.min(Math.max(newzoom, this.minZoom), this.maxZoom)
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if (zoom == this.zoom) {
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return false
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}
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const zoomToCoord = centerCoordViewport || {
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x: this.width / 2,
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y: this.height / 2
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}
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const zoomFactor = (1 / this.zoom) - (1 / zoom)
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this.x -= Math.round(zoomToCoord.x * zoomFactor)
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this.y -= Math.round(zoomToCoord.y * zoomFactor)
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this.zoom = zoom
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return true
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}
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zoomOut(centerCoordViewport) {
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return this.setZoom(this.zoom - this.zoomStep * this.zoom, centerCoordViewport)
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}
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zoomIn(centerCoordViewport) {
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return this.setZoom(this.zoom + this.zoomStep * this.zoom, centerCoordViewport)
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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, rounded
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* @param {x, y} coord
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*/
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viewportToWorld(coord) {
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const worldCoord = this.viewportToWorldRaw(coord)
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return {
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x: Math.round(worldCoord.x),
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y: Math.round(worldCoord.y),
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}
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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, not rounded
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* @param {x, y} coord
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*/
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viewportToWorldRaw(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, rounded
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* @param {x, y} coord
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*/
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worldToViewport(coord) {
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const viewportCoord = this.worldToViewportRaw(coord)
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return {
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x: Math.round(viewportCoord.x),
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y: Math.round(viewportCoord.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, not rounded
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* @param {x, y} coord
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*/
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worldToViewportRaw(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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/**
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* Translate a 2d dimension (width/height) in the world to
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* one in the viewport, rounded
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* @param {x, y} coord
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*/
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worldDimToViewport(dim) {
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const viewportDim = this.worldDimToViewportRaw(dim)
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return {
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w: Math.round(viewportDim.w),
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h: Math.round(viewportDim.h),
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}
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}
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/**
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* Translate a 2d dimension (width/height) in the world to
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* one in the viewport, not rounded
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* @param {x, y} coord
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*/
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worldDimToViewportRaw(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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