shaku/src/gfx/camera.js

A simple and effective JavaScript game development framework that knows its place!

/**
 * Camera class.
 * 
 * |-- copyright and license --|
 * @module     Shaku
 * @file       shaku\src\gfx\camera.js
 * @author     Ronen Ness (ronenness@gmail.com | http://ronenness.com)
 * @copyright  (c) 2021 Ronen Ness
 * @license    MIT
 * |-- end copyright and license --|
 * 
 */
 'use strict';

const Rectangle = require("../utils/rectangle");
const Vector2 = require("../utils/vector2");
const Matrix = require('../utils/matrix.js');
const Vector3 = require("../utils/vector3");
const Frustum = require("../utils/frustum");

 /**
  * Implements a Camera object.
  */
class Camera
{
    /**
     * Create the camera.
     * @param {Gfx} gfx The gfx manager instance.
     */
    constructor(gfx)
    {
        this.__region = null;
        this.__gfx = gfx;
        this.__viewport = null;
        this.orthographic();
    }

    /**
     * Get camera's viewport (drawing region to set when using this camera).
     * @returns {Rectangle} Camera's viewport as rectangle.
     */
    get viewport()
    {
        return this.__viewport;
    }

    /**
     * Set camera's viewport.
     * @param {Rectangle} viewport New viewport to set or null to not use any viewport when using this camera.
     */
    set viewport(viewport)
    {
        this.__viewport = viewport;
        return viewport;
    }

    /**
     * Get the region this camera covers.
     * @returns {Rectangle} region this camera covers.
     */
    getRegion()
    {
        return this.__region.clone();
    }

    /**
     * Make this camera an orthographic camera with offset.
     * @param {Vector2} offset Camera offset (top-left corner).
     * @param {Boolean} ignoreViewportSize If true, will take the entire canvas size for calculation and ignore the viewport size, if set.
     * @param {Number} near Near clipping plane.
     * @param {Number} far Far clipping plane.
     */
    orthographicOffset(offset, ignoreViewportSize, near, far)
    {
        let renderingSize = (ignoreViewportSize || !this.viewport) ? this.__gfx.getCanvasSize() : this.viewport.getSize();
        let region = new Rectangle(offset.x, offset.y, renderingSize.x, renderingSize.y);
        this.orthographic(region, near, far);
    }

    /**
     * Make this camera an orthographic camera.
     * @param {Rectangle} region Camera left, top, bottom and right. If not set, will take entire canvas.
     * @param {Number} near Near clipping plane.
     * @param {Number} far Far clipping plane.
     */
    orthographic(region, near, far) 
    {
        if (region === undefined) {
            region = this.__gfx._internal.getRenderingRegionInternal();
        }
        this.__region = region;
        this.projection = Matrix.createOrthographic(region.left, region.right, region.bottom, region.top, near || -1, far || 400);
    }
}

// export the camera object
module.exports = Camera;