@openhps/core/dist/esm/three/renderers/common/RenderContexts.js

Open Hybrid Positioning System - Core component

import ChainMap from './ChainMap.js';
import RenderContext from './RenderContext.js';
import { Scene } from '../../scenes/Scene.js';
import { Camera } from '../../cameras/Camera.js';
const _chainKeys = [];
const _defaultScene = /*@__PURE__*/new Scene();
const _defaultCamera = /*@__PURE__*/new Camera();

/**
 * This module manages the render contexts of the renderer.
 *
 * @private
 */
class RenderContexts {
  /**
   * Constructs a new render context management component.
   */
  constructor() {
    /**
     * A dictionary that manages render contexts in chain maps
     * for each attachment state.
     *
     * @type {Object<string,ChainMap>}
     */
    this.chainMaps = {};
  }

  /**
   * Returns a render context for the given scene, camera and render target.
   *
   * @param {Scene} scene - The scene.
   * @param {Camera} camera - The camera that is used to render the scene.
   * @param {?RenderTarget} [renderTarget=null] - The active render target.
   * @return {RenderContext} The render context.
   */
  get(scene, camera, renderTarget = null) {
    _chainKeys[0] = scene;
    _chainKeys[1] = camera;
    let attachmentState;
    if (renderTarget === null) {
      attachmentState = 'default';
    } else {
      const format = renderTarget.texture.format;
      const count = renderTarget.textures.length;
      attachmentState = `${count}:${format}:${renderTarget.samples}:${renderTarget.depthBuffer}:${renderTarget.stencilBuffer}`;
    }
    const chainMap = this._getChainMap(attachmentState);
    let renderState = chainMap.get(_chainKeys);
    if (renderState === undefined) {
      renderState = new RenderContext();
      chainMap.set(_chainKeys, renderState);
    }
    _chainKeys.length = 0;
    if (renderTarget !== null) renderState.sampleCount = renderTarget.samples === 0 ? 1 : renderTarget.samples;
    return renderState;
  }

  /**
   * Returns a render context intended for clear operations.
   *
   * @param {?RenderTarget} [renderTarget=null] - The active render target.
   * @return {RenderContext} The render context.
   */
  getForClear(renderTarget = null) {
    return this.get(_defaultScene, _defaultCamera, renderTarget);
  }

  /**
   * Returns a chain map for the given attachment state.
   *
   * @private
   * @param {string} attachmentState - The attachment state.
   * @return {ChainMap} The chain map.
   */
  _getChainMap(attachmentState) {
    return this.chainMaps[attachmentState] || (this.chainMaps[attachmentState] = new ChainMap());
  }

  /**
   * Frees internal resources.
   */
  dispose() {
    this.chainMaps = {};
  }
}
export default RenderContexts;