mirror of
https://github.com/greggman/twgl.js.git
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389 lines
12 KiB
HTML
389 lines
12 KiB
HTML
<!DOCTYPE html>
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<html>
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<head>
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<meta charset="utf8">
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<!--
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@license twgl.js Copyright (c) 2015, Gregg Tavares All Rights Reserved.
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Available via the MIT license.
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see: http://github.com/greggman/twgl.js for details
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-->
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<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
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<meta property="og:title" content="TWGL.js - picking" />
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<meta property="og:type" content="website" />
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<meta property="og:image" content="http://twgljs.org/examples/screenshots/picking.png" />
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<meta property="og:description" content="TWGL.js - picking" />
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<meta property="og:url" content="http://twgljs.org" />
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<meta name="twitter:card" content="summary_large_image">
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<meta name="twitter:site" content="@greggman">
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<meta name="twitter:creator" content="@greggman">
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<meta name="twitter:domain" content="twgljs.org">
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<meta name="twitter:title" content="TWGL.js - picking">
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<meta name="twitter:url" content="http://twgljs.org/examples/picking.html">
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<meta name="twitter:description" content="TWGL.js - picking">
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<meta name="twitter:image:src" content="http://twgljs.org/examples/screenshots/picking.png">
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<link href="/resources/images/twgljs-icon.png" rel="shortcut icon" type="image/png">
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<title>twgl.js - picking (bad)</title>
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<style>
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*, *:before, *:after {
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-webkit-user-select: none;
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-moz-user-select: none;
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-ms-user-select: none;
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user-select: none;
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}
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html, body {
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margin: 0;
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font-family: monospace;
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height: 100%;
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}
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canvas {
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display: block;
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width: 100%;
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height: 100%;
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}
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#b {
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position: absolute;
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top: 10px;
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width: 100%;
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text-align: center;
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z-index: 2;
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}
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</style>
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</head>
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<body>
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<canvas id="c"></canvas>
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<div id="b"><a href="http://twgljs.org">twgl.js</a> - picking (bad)</div>
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</body>
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<script id="vs" type="notjs">
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uniform mat4 u_worldViewProjection;
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uniform vec3 u_lightWorldPos;
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uniform mat4 u_world;
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uniform mat4 u_viewInverse;
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uniform mat4 u_worldInverseTranspose;
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attribute vec4 a_position;
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attribute vec3 a_normal;
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attribute vec2 a_texcoord;
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varying vec4 v_position;
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varying vec2 v_texCoord;
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varying vec3 v_normal;
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varying vec3 v_surfaceToLight;
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varying vec3 v_surfaceToView;
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void main() {
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v_texCoord = a_texcoord;
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v_position = (u_worldViewProjection * a_position);
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v_normal = (u_worldInverseTranspose * vec4(a_normal, 0)).xyz;
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v_surfaceToLight = u_lightWorldPos - (u_world * a_position).xyz;
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v_surfaceToView = (u_viewInverse[3] - (u_world * a_position)).xyz;
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gl_Position = v_position;
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}
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</script>
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<script id="fs" type="notjs">
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precision mediump float;
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varying vec4 v_position;
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varying vec2 v_texCoord;
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varying vec3 v_normal;
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varying vec3 v_surfaceToLight;
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varying vec3 v_surfaceToView;
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uniform vec4 u_lightColor;
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uniform vec4 u_diffuseMult;
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uniform vec4 u_flashColor;
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uniform sampler2D u_diffuse;
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uniform vec4 u_specular;
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uniform float u_shininess;
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uniform float u_specularFactor;
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vec4 lit(float l ,float h, float m) {
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return vec4(1.0,
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abs(l),//max(l, 0.0),
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(l > 0.0) ? pow(max(0.0, h), m) : 0.0,
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1.0);
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}
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void main() {
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vec4 diffuseColor = texture2D(u_diffuse, v_texCoord) * u_diffuseMult;
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vec3 a_normal = normalize(v_normal);
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vec3 surfaceToLight = normalize(v_surfaceToLight);
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vec3 surfaceToView = normalize(v_surfaceToView);
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vec3 halfVector = normalize(surfaceToLight + surfaceToView);
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vec4 litR = lit(dot(a_normal, surfaceToLight),
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dot(a_normal, halfVector), u_shininess);
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vec4 outColor = vec4((
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u_lightColor * (diffuseColor * litR.y +
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u_specular * litR.z * u_specularFactor)).rgb,
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diffuseColor.a);
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gl_FragColor = outColor + u_flashColor;
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}
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</script>
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<script id="picking-vs" type="notjs">
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uniform mat4 u_worldViewProjection;
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attribute vec4 a_position;
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attribute vec2 a_texcoord;
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varying vec2 v_texCoord;
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void main() {
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v_texCoord = a_texcoord;
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gl_Position = u_worldViewProjection * a_position;
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}
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</script>
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<script id="picking-fs" type="notjs">
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precision mediump float;
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varying vec2 v_texCoord;
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uniform float u_threshhold;
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uniform vec4 u_pickColor;
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uniform vec4 u_diffuseMult;
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uniform sampler2D u_diffuse;
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void main() {
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vec4 diffuseColor = texture2D(u_diffuse, v_texCoord) * u_diffuseMult;
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if (diffuseColor.a <= u_threshhold) {
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discard;
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}
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gl_FragColor = u_pickColor;
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}
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</script>
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<script src="../3rdparty/chroma.min.js"></script>
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<script type="module">
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import * as twgl from '../dist/7.x/twgl-full.module.js';
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twgl.setDefaults({attribPrefix: "a_"});
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const m4 = twgl.m4;
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const gl = document.querySelector("#c").getContext("webgl");
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const programInfo = twgl.createProgramInfo(gl, ["vs", "fs"]);
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const pickingProgramInfo = twgl.createProgramInfo(gl, ["picking-vs", "picking-fs"]);
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const shapes = [
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twgl.primitives.createCubeBufferInfo(gl, 2),
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twgl.primitives.createSphereBufferInfo(gl, 1, 24, 12),
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twgl.primitives.createPlaneBufferInfo(gl, 2, 2),
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twgl.primitives.createTruncatedConeBufferInfo(gl, 1, 0, 2, 24, 1),
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twgl.primitives.createCresentBufferInfo(gl, 1, 1, 0.5, 0.1, 24),
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twgl.primitives.createCylinderBufferInfo(gl, 1, 2, 24, 2),
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twgl.primitives.createDiscBufferInfo(gl, 1, 24),
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twgl.primitives.createTorusBufferInfo(gl, 1, 0.4, 24, 12),
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];
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function rand(min, max) {
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return min + Math.random() * (max - min);
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}
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let pickId = -1;
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// Shared values
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const lightWorldPosition = [1, 8, -10];
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const lightColor = [1, 1, 1, 1];
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const camera = m4.identity();
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const view = m4.identity();
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const viewProjection = m4.identity();
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const tex = twgl.createTexture(gl, {
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min: gl.NEAREST,
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mag: gl.NEAREST,
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src: [
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255, 255, 255, 255,
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192, 192, 192, 255,
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192, 192, 192, 255,
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255, 255, 255, 255,
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],
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});
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function makePickingColor(id) {
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return [
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((id >> 0) & 0xFF) / 0xFF,
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((id >> 8) & 0xFF) / 0xFF,
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((id >> 16) & 0xFF) / 0xFF,
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((id >> 24) & 0xFF) / 0xFF,
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];
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}
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const objects = [];
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const drawObjects = [];
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const pickDrawObjects = [];
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const numObjects = 100;
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const baseHue = rand(0, 360);
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for (let ii = 0; ii < numObjects; ++ii) {
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const uniforms = {
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u_lightWorldPos: lightWorldPosition,
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u_lightColor: lightColor,
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u_diffuseMult: chroma.hsv((baseHue + rand(0, 60)) % 360, 0.4, 0.8).gl(),
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u_flashColor: [0, 0, 0, 0],
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u_specular: [1, 1, 1, 1],
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u_shininess: 50,
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u_specularFactor: 1,
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u_diffuse: tex,
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u_viewInverse: camera,
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u_world: m4.identity(),
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u_worldInverseTranspose: m4.identity(),
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u_worldViewProjection: m4.identity(),
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u_threshhold: 0.1,
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u_pickColor: makePickingColor(ii),
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};
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drawObjects.push({
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programInfo: programInfo,
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bufferInfo: shapes[ii % shapes.length],
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uniforms: uniforms,
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});
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pickDrawObjects.push({
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programInfo: pickingProgramInfo,
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bufferInfo: shapes[ii % shapes.length],
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uniforms: uniforms,
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});
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objects.push({
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translation: [rand(-10, 10), rand(-10, 10), rand(-10, 10)],
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ySpeed: rand(0.1, 0.3),
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zSpeed: rand(0.1, 0.3),
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uniforms: uniforms,
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});
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}
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const pickingFBI = twgl.createFramebufferInfo(gl);
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// NOTE: !!
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//
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// Picking doesn't really make sense in TWGL. Picking requires structure
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// There must be some kind of database or scene graph of things to pick.
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// TWGL doesn't impose any kind of database or scene graph because it's
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// just a set of helpers for raw WebGL. Any structure on top of TWGL is
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// your structure.
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//
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// It also requires some kind of material stucture so that all objects
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// can be rendered with both whatever shader(s) render them normally
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// AND a shader for picking.
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//
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// THREE.js on the other hand has a scene graph that contains objects
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// so it makes sense to be able to pick one of those objects. It also
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// contains various materials and shader generators and imposes a
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// standard structure on those, what their inputs are etc.
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//
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// The code in this exampele was just the quickest thing I could think
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// of to make picking example. It's the primitives.html example
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//
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// It works by
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//
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// 1. Making the picking shader compatible with the phong shader
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//
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// 2. Making the 2 shaders use the same uniforms
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//
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// Since they use the same uniforms then when drawing the picking
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// there are no matricies to set because we already set them all
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// last time things were drawn.
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//
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// 3. Adding a u_flashColor uniform to the phong shader
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//
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// 4. Having 2 parallel drawObjectList lists. One for drawing, one for picking
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//
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// Effectively it's a big hack that has nothing to do with the structure of
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// a program that would actually be used to pick something
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//
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// On the other hand what it does show is
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//
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// 1. using `twgl.createFrameBufferInfo` to create an RGBA + Depth buffer
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// the same size as the canvas which is the default with no arguments
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//
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// 2. using `twgl.resizeFramebufferInfo` to match the new size of the canvas
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// again the default with no extra arguments
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//
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// 3. indirectly the fact that `twgl.bindFramebufferInfo` sets the viewport
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//
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// 4. examples of getting a relative mouse and/or touch position
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//
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// NOTE: it assumes the canvas has no border, padding, margin.
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function pickObject(inputX, inputY) {
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// If something is picked restore its color
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if (pickId >= 0 && pickId < objects.length) {
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const object = objects[pickId];
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object.uniforms.u_flashColor = [0, 0, 0, 0];
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}
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const rect = gl.canvas.getBoundingClientRect();
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const w = gl.canvas.clientWidth;
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const h = gl.canvas.clientHeight;
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const x = (inputX - rect.left) * gl.canvas.width / w | 0;
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const y = gl.canvas.height - ((inputY - rect.top ) * gl.canvas.height / h | 0) - 1;
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// resize pickingFBI to match canvas
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twgl.resizeFramebufferInfo(gl, pickingFBI);
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twgl.bindFramebufferInfo(gl, pickingFBI);
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gl.clearColor(1, 1, 1, 1);
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gl.enable(gl.DEPTH_TEST);
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gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT | gl.STENCIL_BUFFER_BIT);
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twgl.drawObjectList(gl, pickDrawObjects);
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const pickColor = new Uint8Array(4);
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gl.readPixels(x, y, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, pickColor);
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pickId = (pickColor[0] << 0) +
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(pickColor[1] << 8) +
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(pickColor[2] << 16) +
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(pickColor[3] << 24);
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}
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gl.canvas.addEventListener('click', function(e) {
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pickObject(e.clientX, e.clientY);
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});
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gl.canvas.addEventListener('touchstart', function(e) {
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e.preventDefault();
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pickObject(e.touches[0].clientX, e.touches[0].clientY);
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});
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gl.canvas.addEventListener('contextmenu', function(e) {
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e.preventDefault();
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return false;
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});
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function render(time) {
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time *= 0.001;
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twgl.resizeCanvasToDisplaySize(gl.canvas);
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twgl.bindFramebufferInfo(gl, null);
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gl.enable(gl.DEPTH_TEST);
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gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
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const projection = m4.perspective(30 * Math.PI / 180, gl.canvas.clientWidth / gl.canvas.clientHeight, 0.5, 100);
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const eye = [1, 4, -20];
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const target = [0, 0, 0];
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const up = [0, 1, 0];
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m4.lookAt(eye, target, up, camera);
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m4.inverse(camera, view);
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m4.multiply(projection, view, viewProjection);
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objects.forEach(function(obj) {
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const uni = obj.uniforms;
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const world = uni.u_world;
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m4.identity(world);
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m4.rotateY(world, time * obj.ySpeed, world);
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m4.rotateZ(world, time * obj.zSpeed, world);
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m4.translate(world, obj.translation, world);
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m4.rotateX(world, time, world);
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m4.transpose(m4.inverse(world, uni.u_worldInverseTranspose), uni.u_worldInverseTranspose);
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m4.multiply(viewProjection, uni.u_world, uni.u_worldViewProjection);
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});
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// If something is picked flash its color
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if (pickId >= 0 && pickId < objects.length) {
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const object = objects[pickId];
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object.uniforms.u_flashColor = ((time * 20 | 0) % 2) ? [0.2, 0.2, 0.2, 0.2] : [1, 0, 0, 1];
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}
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twgl.drawObjectList(gl, drawObjects);
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requestAnimationFrame(render);
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}
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requestAnimationFrame(render);
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</script>
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</html>
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