Renderers/RenderTexture.js

import Color from '../Color';
import Image from '../Image';
import RenderTarget from './RenderTarget';
import Texture from '../Textures/Texture';
import WebGL from './WebGL/RenderWebGL';

/**
 * A rendering texture: Supported by WebGL only.
 *
 * @category Rendering
 * @extends {RenderTarget}
 */
class RenderTexture extends RenderTarget {
    /**
     * Constructor
     *
     * @param {number} width Texture's width
     * @param {number} height Texture's height
     * @param {number} textureCount Texture count
     * @param {boolean=} useDepthBuffer True to use a depth buffer
     * @param {boolean=} useStencilBuffer True to use a stencil buffer
     */
    constructor(width, height, textureCount, useDepthBuffer = true, useStencilBuffer = false) {
        super();

        /**
         * The render API to use
         *
         * @type {RenderAPI}
         * @protected
         */
        this.renderApi = WebGL.getInstance();

        /**
         * Frame buffer identifier
         *
         * @type {number}
         * @private
         */
        this.framebuffer = this.renderApi.createFrameBuffer();

        /**
         * An array with the textures to draw in
         *
         * @type {Array.<Texture>}
         * @private
         */
        this.textures = [];

        // Init the render texture
        this.init(width, height, textureCount, useDepthBuffer, useStencilBuffer);
    }

    /**
     * Init
     *
     * @param {number} width Texture's width
     * @param {number} height Texture's height
     * @param {number} textureCount Texture count
     * @param {boolean=} useDepthBuffer True to use a depth buffer
     * @param {boolean=} useStencilBuffer True to use a depth buffer
     * @private
     */
    init(width, height, textureCount, useDepthBuffer = true, useStencilBuffer = false) {
        // Create textures.
        for (let i = 0; i < textureCount; i += 1) {
            const image = new Image();
            image.create(width, height, null);

            const texture = new Texture();
            texture.setRepeated(false);
            texture.setSmooth(true);
            texture.useMipmap(false);
            texture.loadFromImage(image);
            this.textures.push(texture);
        }

        // Attach the texture to the frame buffer
        this.renderApi.initFrameBuffer(this.framebuffer, this.textures, useDepthBuffer, useStencilBuffer);
    }

    /**
     * Clear the texture
     *
     * @param {?Color} color A Color instance
     */
    clear(color = new Color(0, 0, 0)) {
        // Remove previous tasks.
        this.removeTasks();

        // Bind frame buffer.
        this.begin();

        // Clear screen.
        this.renderApi.clear(color);
    }

    /**
     * Begin rendering to texture
     */
    begin() {
        this.renderApi.bindFrameBuffer(this.framebuffer);
    }

    /**
     * Display
     */
    display() {
        super.display();

        // Go back to the default buffer
        this.renderApi.bindFrameBuffer(-1);
    }

    /**
     * Output Textures
     *
     * @return {Array.<Texture>} An array of Texture
     */
    getTextures() {
        return this.textures;
    }
}

export default RenderTexture;