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2 years ago
<!DOCTYPE html>
<html lang="en">
<head>
<title>three.js webgl - read float pixels</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
<link type="text/css" rel="stylesheet" href="main.css">
</head>
<body>
<div id="container"></div>
<div id="info">
<a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> read float pixels webgl example<br/>
<span id="values"></span>
</div>
<script id="fragment_shader_screen" type="x-shader/x-fragment">
varying vec2 vUv;
uniform sampler2D tDiffuse;
void main() {
gl_FragColor = texture2D( tDiffuse, vUv );
}
</script>
<script id="fragment_shader_pass_1" type="x-shader/x-fragment">
varying vec2 vUv;
uniform float time;
void main() {
float r = vUv.x;
if( vUv.y < 0.5 ) r = 0.0;
float g = vUv.y;
if( vUv.x < 0.5 ) g = 0.0;
gl_FragColor = vec4( r, g, time, 1.0 );
}
</script>
<script id="vertexShader" type="x-shader/x-vertex">
varying vec2 vUv;
void main() {
vUv = uv;
gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );
}
</script>
<!-- Import maps polyfill -->
<!-- Remove this when import maps will be widely supported -->
<script async src="https://unpkg.com/es-module-shims@1.3.6/dist/es-module-shims.js"></script>
<script type="importmap">
{
"imports": {
"three": "../build/three.module.js",
"three/addons/": "./jsm/"
}
}
</script>
<script type="module">
import * as THREE from 'three';
import Stats from 'three/addons/libs/stats.module.js';
let container, stats;
let cameraRTT, sceneRTT, sceneScreen, renderer, zmesh1, zmesh2;
let mouseX = 0, mouseY = 0;
const windowHalfX = window.innerWidth / 2;
const windowHalfY = window.innerHeight / 2;
let rtTexture, material, quad;
let delta = 0.01;
let valueNode;
init();
animate();
function init() {
container = document.getElementById( 'container' );
cameraRTT = new THREE.OrthographicCamera( window.innerWidth / - 2, window.innerWidth / 2, window.innerHeight / 2, window.innerHeight / - 2, - 10000, 10000 );
cameraRTT.position.z = 100;
//
sceneRTT = new THREE.Scene();
sceneScreen = new THREE.Scene();
let light = new THREE.DirectionalLight( 0xffffff );
light.position.set( 0, 0, 1 ).normalize();
sceneRTT.add( light );
light = new THREE.DirectionalLight( 0xffaaaa, 1.5 );
light.position.set( 0, 0, - 1 ).normalize();
sceneRTT.add( light );
rtTexture = new THREE.WebGLRenderTarget( window.innerWidth, window.innerHeight, { minFilter: THREE.LinearFilter, magFilter: THREE.NearestFilter, format: THREE.RGBAFormat, type: THREE.FloatType } );
material = new THREE.ShaderMaterial( {
uniforms: { 'time': { value: 0.0 } },
vertexShader: document.getElementById( 'vertexShader' ).textContent,
fragmentShader: document.getElementById( 'fragment_shader_pass_1' ).textContent
} );
const materialScreen = new THREE.ShaderMaterial( {
uniforms: { 'tDiffuse': { value: rtTexture.texture } },
vertexShader: document.getElementById( 'vertexShader' ).textContent,
fragmentShader: document.getElementById( 'fragment_shader_screen' ).textContent,
depthWrite: false
} );
const plane = new THREE.PlaneGeometry( window.innerWidth, window.innerHeight );
quad = new THREE.Mesh( plane, material );
quad.position.z = - 100;
sceneRTT.add( quad );
const geometry = new THREE.TorusGeometry( 100, 25, 15, 30 );
const mat1 = new THREE.MeshPhongMaterial( { color: 0x555555, specular: 0xffaa00, shininess: 5 } );
const mat2 = new THREE.MeshPhongMaterial( { color: 0x550000, specular: 0xff2200, shininess: 5 } );
zmesh1 = new THREE.Mesh( geometry, mat1 );
zmesh1.position.set( 0, 0, 100 );
zmesh1.scale.set( 1.5, 1.5, 1.5 );
sceneRTT.add( zmesh1 );
zmesh2 = new THREE.Mesh( geometry, mat2 );
zmesh2.position.set( 0, 150, 100 );
zmesh2.scale.set( 0.75, 0.75, 0.75 );
sceneRTT.add( zmesh2 );
quad = new THREE.Mesh( plane, materialScreen );
quad.position.z = - 100;
sceneScreen.add( quad );
renderer = new THREE.WebGLRenderer();
renderer.setPixelRatio( window.devicePixelRatio );
renderer.setSize( window.innerWidth, window.innerHeight );
renderer.autoClear = false;
container.appendChild( renderer.domElement );
stats = new Stats();
container.appendChild( stats.dom );
valueNode = document.getElementById( 'values' );
document.addEventListener( 'mousemove', onDocumentMouseMove );
}
function onDocumentMouseMove( event ) {
mouseX = ( event.clientX - windowHalfX );
mouseY = ( event.clientY - windowHalfY );
}
//
function animate() {
requestAnimationFrame( animate );
render();
stats.update();
}
function render() {
const time = Date.now() * 0.0015;
if ( zmesh1 && zmesh2 ) {
zmesh1.rotation.y = - time;
zmesh2.rotation.y = - time + Math.PI / 2;
}
if ( material.uniforms[ 'time' ].value > 1 || material.uniforms[ 'time' ].value < 0 ) {
delta *= - 1;
}
material.uniforms[ 'time' ].value += delta;
renderer.clear();
// Render first scene into texture
renderer.setRenderTarget( rtTexture );
renderer.clear();
renderer.render( sceneRTT, cameraRTT );
// Render full screen quad with generated texture
renderer.setRenderTarget( null );
renderer.render( sceneScreen, cameraRTT );
const read = new Float32Array( 4 );
renderer.readRenderTargetPixels( rtTexture, windowHalfX + mouseX, windowHalfY - mouseY, 1, 1, read );
valueNode.innerHTML = 'r:' + read[ 0 ] + '<br/>g:' + read[ 1 ] + '<br/>b:' + read[ 2 ];
}
</script>
</body>
</html>