blaze-2d/lib/src/camera/camera.js

A fast and simple WebGL 2 2D game engine written in TypeScript

import { vec2 } from "gl-matrix";
import Object2D from "../object2d";
import Viewport from "./viewport";
/**
 * Represents the camera in 2D world space.
 *
 * The camera's position is the centre of the viewport.
 */
export default class Camera extends Object2D {
    /**
     * Creates a {@link Camera} instance.
     */
    constructor(centre, vw, vh) {
        super();
        this.zoomLevel = 1;
        this.minZoom = 0.1;
        this.maxZoom = 10;
        this.lastPos = vec2.create();
        this.setPosition(centre);
        if (typeof vw === "number") {
            this.viewport = new Viewport(centre, vw, vh);
        }
        else {
            this.viewport = vw;
        }
    }
    /**
     * Updates the camera's viewport if the camera has changed position since the last call to update.
     */
    update() {
        if (vec2.exactEquals(this.getPosition(), this.lastPos))
            return;
        this.viewport.update(this.getPosition());
        vec2.copy(this.lastPos, this.getPosition());
    }
    /**
     * Zooms the camera by the given amount.
     *
     * @param zoom The amount to zoom by
     */
    zoom(zoom) {
        const newZoom = this.zoomLevel + zoom;
        this.setZoom(newZoom);
    }
    /**
     * Sets the zoom level of the camera.
     *
     * This will change the size of `this.viewport`.
     *
     * @param zoom The zoom level
     */
    setZoom(zoom) {
        // clamp zoom
        this.zoomLevel = Math.max(this.minZoom, Math.min(zoom, this.maxZoom));
        const w = this.viewport.getOriginalWidth() / this.zoomLevel;
        const h = this.viewport.getOriginalHeight() / this.zoomLevel;
        this.viewport.setWidth(w);
        this.viewport.setHeight(h);
    }
    /**
     * Gets the zoom level of the camera.
     *
     * @returns The zoom level of the camera
     */
    getZoom() {
        return this.zoomLevel;
    }
}
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