@animech-public/playcanvas/build/playcanvas.prf/src/framework/graphics/picker.js

PlayCanvas WebGL game engine

import { Color } from '../../core/math/color.js';
import { PIXELFORMAT_RGBA8, FILTER_NEAREST, ADDRESS_CLAMP_TO_EDGE } from '../../platform/graphics/constants.js';
import { GraphicsDevice } from '../../platform/graphics/graphics-device.js';
import { RenderTarget } from '../../platform/graphics/render-target.js';
import { Texture } from '../../platform/graphics/texture.js';
import { Camera } from '../../scene/camera.js';
import { Layer } from '../../scene/layer.js';
import { getApplication } from '../globals.js';
import { RenderPassPicker } from './render-pass-picker.js';

const tempSet = new Set();
class Picker {
	constructor(app, width, height) {
		this.renderTarget = null;
		this.mapping = new Map();
		if (app instanceof GraphicsDevice) {
			app = getApplication();
		}
		this.renderer = app.renderer;
		this.device = app.graphicsDevice;
		this.renderPass = new RenderPassPicker(this.device, app.renderer);
		this.width = 0;
		this.height = 0;
		this.resize(width, height);
	}
	getSelection(x, y, width = 1, height = 1) {
		const device = this.device;
		y = this.renderTarget.height - (y + height);
		x = Math.floor(x);
		y = Math.floor(y);
		width = Math.floor(Math.max(width, 1));
		height = Math.floor(Math.max(height, 1));
		device.setRenderTarget(this.renderTarget);
		device.updateBegin();
		const pixels = new Uint8Array(4 * width * height);
		device.readPixels(x, y, width, height, pixels);
		device.updateEnd();
		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 a = pixels[4 * i + 3];
			const index = a << 24 | r << 16 | g << 8 | b;
			if (index !== -1) {
				tempSet.add(mapping.get(index));
			}
		}
		const selection = [];
		tempSet.forEach(meshInstance => selection.push(meshInstance));
		tempSet.clear();
		return selection;
	}
	allocateRenderTarget() {
		const colorBuffer = new Texture(this.device, {
			format: PIXELFORMAT_RGBA8,
			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() {
		if (this.renderTarget) {
			this.renderTarget.destroyTextureBuffers();
			this.renderTarget.destroy();
			this.renderTarget = null;
		}
	}
	prepare(camera, scene, layers) {
		if (camera instanceof Camera) {
			camera = camera.node.camera;
		}
		if (layers instanceof Layer) {
			layers = [layers];
		}
		if (!this.renderTarget || this.width !== this.renderTarget.width || this.height !== this.renderTarget.height) {
			this.releaseRenderTarget();
			this.allocateRenderTarget();
		}
		this.mapping.clear();
		const renderPass = this.renderPass;
		renderPass.init(this.renderTarget);
		renderPass.colorOps.clearValue = Color.WHITE;
		renderPass.colorOps.clear = true;
		renderPass.depthStencilOps.clearDepth = true;
		renderPass.update(camera, scene, layers, this.mapping);
		renderPass.render();
	}
	resize(width, height) {
		this.width = Math.floor(width);
		this.height = Math.floor(height);
	}
}

export { Picker };