text: import { Color } from '../math/color.js';
  
  import { ADDRESS_CLAMP_TO_EDGE, CLEARFLAG_DEPTH, FILTER_NEAREST, PIXELFORMAT_R8_G8_B8_A8 } from '../graphics/constants.js';
  import { GraphicsDevice } from '../graphics/graphics-device.js';
  import { RenderTarget } from '../graphics/render-target.js';
  import { Texture } from '../graphics/texture.js';
  
  import { SHADER_PICK, SORTMODE_NONE } from './constants.js';
  import { Camera } from './camera.js';
  import { Command } from './mesh-instance.js';
  import { Layer } from './layer.js';
  import { LayerComposition } from './composition/layer-composition.js';
  
  import { getApplication } from '../framework/globals.js';
  import { Entity } from '../framework/entity.js';
  import { Debug } from '../core/debug.js';
  
  /** @typedef {import('../framework/app-base.js').AppBase} AppBase */
  /** @typedef {import('../framework/components/camera/component.js').CameraComponent} CameraComponent */
  /** @typedef {import('./mesh-instance.js').MeshInstance} MeshInstance */
  /** @typedef {import('./scene.js').Scene} Scene */
  
  const tempSet = new Set();
  
  const clearDepthOptions = {
      depth: 1.0,
      flags: CLEARFLAG_DEPTH
  };
  
  /**
   * Picker object used to select mesh instances from screen coordinates.
   *
   * @property {number} width Width of the pick buffer in pixels (read-only).
   * @property {number} height Height of the pick buffer in pixels (read-only).
   * @property {RenderTarget} renderTarget The render target used by the picker internally
   * (read-only).
   */
  class Picker {
      /**
       * Create a new Picker instance.
       *
       * @param {AppBase} app - The application managing this picker instance.
       * @param {number} width - The width of the pick buffer in pixels.
       * @param {number} height - The height of the pick buffer in pixels.
       */
      constructor(app, width, height) {
          if (app instanceof GraphicsDevice) {
              app = getApplication();
              Debug.deprecated('pc.Picker now takes pc.AppBase as first argument. Passing pc.GraphicsDevice is deprecated.');
          }
  
          this.app = app;
          this.device = app.graphicsDevice;
  
          // uniform for the mesh index encoded into rgba
          this.pickColor = new Float32Array(4);
          this.pickColor[3] = 1;
  
          // mapping table from ids to meshInstances
          this.mapping = [];
  
          // create layer composition with the layer and camera
          this.cameraEntity = null;
          this.layer = null;
          this.layerComp = null;
          this.initLayerComposition();
  
          // internal render target
          this._renderTarget = null;
  
          // clear command user to simulate layer clearing, required due to storing meshes from multiple layers on a singe layer
          const device = this.device;
          this.clearDepthCommand = new Command(0, 0, function () {
              device.clear(clearDepthOptions);
          });
  
          this.width = 0;
          this.height = 0;
          this.resize(width, height);
      }
  
      /**
       * Return the list of mesh instances selected by the specified rectangle in the previously
       * prepared pick buffer.The rectangle using top-left coordinate system.
       *
       * @param {number} x - The left edge of the rectangle.
       * @param {number} y - The top edge of the rectangle.
       * @param {number} [width] - The width of the rectangle.
       * @param {number} [height] - The height of the rectangle.
       * @returns {MeshInstance[]} An array of mesh instances that are in the selection.
       * @example
       * // Get the selection at the point (10,20)
       * var selection = picker.getSelection(10, 20);
       * @example
       * // Get all models in rectangle with corners at (10,20) and (20,40)
       * var selection = picker.getSelection(10, 20, 10, 20);
       */
      getSelection(x, y, width, height) {
          const device = this.device;
  
          if (typeof x === 'object') {
              Debug.deprecated('Picker.getSelection:param \'rect\' is deprecated, use \'x, y, width, height\' instead.');
  
              const rect = x;
              x = rect.x;
              y = rect.y;
              width = rect.width;
              height = rect.height;
          } else {
              y = this.renderTarget.height - (y + (height || 1));
          }
  
          // make sure we have nice numbers to work with
          x = Math.floor(x);
          y = Math.floor(y);
          width = Math.floor(Math.max(width || 1, 1));
          height = Math.floor(Math.max(height || 1, 1));
  
          // backup active render target
          const origRenderTarget = device.renderTarget;
  
          // Ready the device for rendering to the pick buffer
          device.setRenderTarget(this.renderTarget);
          device.updateBegin();
  
          const pixels = new Uint8Array(4 * width * height);
          device.readPixels(x, y, width, height, pixels);
  
          device.updateEnd();
  
          // Restore render target
          device.setRenderTarget(origRenderTarget);
  
          const mapping = this.mapping;
          for (let i = 0; i < width * height; i++) {
              const r = pixels[4 * i + 0];
              const g = pixels[4 * i + 1];
              const b = pixels[4 * i + 2];
              const index = r << 16 | g << 8 | b;
  
              // White is 'no selection'
              if (index !== 0xffffff) {
                  tempSet.add(mapping[index]);
              }
          }
  
          // return the content of the set as an array
          const selection = [];
          tempSet.forEach(meshInstance => selection.push(meshInstance));
          tempSet.clear();
  
          return selection;
      }
  
      allocateRenderTarget() {
  
          const colorBuffer = new Texture(this.device, {
              format: PIXELFORMAT_R8_G8_B8_A8,
              width: this.width,
              height: this.height,
              mipmaps: false,
              minFilter: FILTER_NEAREST,
              magFilter: FILTER_NEAREST,
              addressU: ADDRESS_CLAMP_TO_EDGE,
              addressV: ADDRESS_CLAMP_TO_EDGE,
              name: 'pick'
          });
  
          this.renderTarget = new RenderTarget({
              colorBuffer: colorBuffer,
              depth: true
          });
      }
  
      releaseRenderTarget() {
  
          // unset it from the camera
          this.cameraEntity.camera.renderTarget = null;
  
          if (this._renderTarget) {
              this._renderTarget._colorBuffer.destroy();
              this._renderTarget.destroy();
              this._renderTarget = null;
          }
      }
  
      initLayerComposition() {
  
          const device = this.device;
          const self = this;
          const pickColorId = device.scope.resolve('uColor');
  
          // camera
          this.cameraEntity = new Entity();
          this.cameraEntity.addComponent('camera');
  
          // layer all meshes rendered for picking at added to
          this.layer = new Layer({
              name: 'Picker',
              shaderPass: SHADER_PICK,
              opaqueSortMode: SORTMODE_NONE,
  
              // executes just before the mesh is rendered. And index encoded in rgb is assigned to it
              onDrawCall: function (meshInstance, index) {
                  self.pickColor[0] = ((index >> 16) & 0xff) / 255;
                  self.pickColor[1] = ((index >> 8) & 0xff) / 255;
                  self.pickColor[2] = (index & 0xff) / 255;
                  pickColorId.setValue(self.pickColor);
                  device.setBlending(false);
  
                  // keep the index -> meshInstance index mapping
                  self.mapping[index] = meshInstance;
              }
          });
          this.layer.addCamera(this.cameraEntity.camera);
  
          // composition
          this.layerComp = new LayerComposition('picker');
          this.layerComp.pushOpaque(this.layer);
      }
  
      /**
       * Primes the pick buffer with a rendering of the specified models from the point of view of
       * the supplied camera. Once the pick buffer has been prepared, {@link Picker#getSelection} can
       * be called multiple times on the same picker object. Therefore, if the models or camera do
       * not change in any way, {@link Picker#prepare} does not need to be called again.
       *
       * @param {CameraComponent} camera - The camera component used to render the scene.
       * @param {Scene} scene - The scene containing the pickable mesh instances.
       * @param {Layer[]} [layers] - Layers from which objects will be picked. If not supplied, all layers of the specified camera will be used.
       */
      prepare(camera, scene, layers) {
  
          // handle deprecated arguments
          if (camera instanceof Camera) {
              Debug.deprecated('pc.Picker#prepare now takes pc.CameraComponent as first argument. Passing pc.Camera is deprecated.');
  
              // Get the camera component
              camera = camera.node.camera;
          }
  
          if (layers instanceof Layer) {
              layers = [layers];
          }
  
          // populate the layer with meshes and depth clear commands
          this.layer.clearMeshInstances();
          const destMeshInstances = this.layer.opaqueMeshInstances;
  
          // source mesh instances
          const srcLayers = scene.layers.layerList;
          const subLayerEnabled = scene.layers.subLayerEnabled;
          const isTransparent = scene.layers.subLayerList;
  
          for (let i = 0; i < srcLayers.length; i++) {
              const srcLayer = srcLayers[i];
  
              // skip the layer if it does not match the provided ones
              if (layers && layers.indexOf(srcLayer) < 0) {
                  continue;
              }
  
              if (srcLayer.enabled && subLayerEnabled[i]) {
  
                  // if the layer is rendered by the camera
                  const layerCamId = srcLayer.cameras.indexOf(camera);
                  if (layerCamId >= 0) {
  
                      // if the layer clears the depth, add command to clear it
                      if (srcLayer._clearDepthBuffer) {
                          destMeshInstances.push(this.clearDepthCommand);
                      }
  
                      // copy all pickable mesh instances
                      const meshInstances = isTransparent[i] ? srcLayer.instances.transparentMeshInstances : srcLayer.instances.opaqueMeshInstances;
                      for (let j = 0; j < meshInstances.length; j++) {
                          const meshInstance = meshInstances[j];
                          if (meshInstance.pick) {
                              destMeshInstances.push(meshInstance);
                          }
                      }
                  }
              }
          }
  
          // make the render target the right size
          if (!this.renderTarget || (this.width !== this.renderTarget.width || this.height !== this.renderTarget.height)) {
              this.releaseRenderTarget();
              this.allocateRenderTarget();
          }
  
          // prepare the rendering camera
          this.updateCamera(camera);
  
          // clear registered meshes mapping
          this.mapping.length = 0;
  
          // render
          this.app.renderer.renderComposition(this.layerComp);
      }
  
      updateCamera(srcCamera) {
  
          // copy transform
          this.cameraEntity.copy(srcCamera.entity);
          this.cameraEntity.name = 'PickerCamera';
  
          // copy camera component properties - which overwrites few properties we change to what is needed later
          const destCamera = this.cameraEntity.camera;
          destCamera.copy(srcCamera);
  
          // set up clears
          destCamera.clearColorBuffer = true;
          destCamera.clearDepthBuffer = true;
          destCamera.clearStencilBuffer = true;
          destCamera.clearColor = Color.WHITE;
  
          // render target
          destCamera.renderTarget = this.renderTarget;
  
          // layers
          this.layer.clearCameras();
          this.layer.addCamera(destCamera);
          destCamera.layers = [this.layer.id];
      }
  
      /**
       * Sets the resolution of the pick buffer. The pick buffer resolution does not need to match
       * the resolution of the corresponding frame buffer use for general rendering of the 3D scene.
       * However, the lower the resolution of the pick buffer, the less accurate the selection
       * results returned by {@link Picker#getSelection}. On the other hand, smaller pick buffers
       * will yield greater performance, so there is a trade off.
       *
       * @param {number} width - The width of the pick buffer in pixels.
       * @param {number} height - The height of the pick buffer in pixels.
       */
      resize(width, height) {
          this.width = Math.floor(width);
          this.height = Math.floor(height);
      }
  }
  
  export { Picker };
  