I am study render 3Dtexture with a unity demo ===>Unity - Manual: 3D textures, the unity demo render result is
by my result is
I seems three.js data3dTexture only read Red Pixel
And here is my code
three.js webgl2 - volumeBlockquote
<body>
<div id="info">
<a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> webgl2 - volume
</div>
<script type="importmap">
{
"imports": {
"three": "../build/three.module.js",
"three/addons/": "./jsm/"
}
}
</script>
<script type="module">
import * as THREE from 'three';
import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
import { GUI } from 'three/addons/libs/lil-gui.module.min.js';
let renderer, scene, camera;
let mesh;
init();
animate();
function init() {
renderer = new THREE.WebGLRenderer();
renderer.setPixelRatio( window.devicePixelRatio );
renderer.setSize( window.innerWidth, window.innerHeight );
document.body.appendChild( renderer.domElement );
scene = new THREE.Scene();
camera = new THREE.PerspectiveCamera( 60, window.innerWidth / window.innerHeight, 0.1, 100 );
camera.position.set( 0, 0, 2 );
new OrbitControls( camera, renderer.domElement );
// Texture
let i = 0;
const size = 32;
const data = new Uint8Array( size * size * size );
let inverseResolution = 1.0 / (size - 1.0);
for (let z = 0; z < size; z++)
{
let zOffset = z * size * size;
for (let y = 0; y < size; y++)
{
let yOffset = y * size;
for (let x = 0; x < size; x++)
{
const index = x + yOffset + zOffset;
data[index] = (x * inverseResolution)*128+128;
data[index+1] = (y * inverseResolution)*128+128;
data[index+2] = (z * inverseResolution)*128+128;
}
}
}
const texture = new THREE.Data3DTexture( data, size, size, size );
texture.format = THREE.RedFormat;
// texture.type = THREE.Float;
texture.minFilter = THREE.LinearFilter;
texture.magFilter = THREE.LinearFilter;
texture.unpackAlignment = 4;
texture.needsUpdate = true;
// Material
const vertexShader = /* glsl */`
in vec3 position;
uniform mat4 modelMatrix;
uniform mat4 modelViewMatrix;
uniform mat4 projectionMatrix;
uniform vec3 cameraPos;
out vec3 vOrigin;
out vec3 vDirection;
void main() {
vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );
vOrigin = vec3( inverse( modelMatrix ) * vec4( cameraPos, 1.0 ) ).xyz;
vDirection = position - vOrigin;
gl_Position = projectionMatrix * mvPosition;
}
`;
const fragmentShader = /* glsl */`
precision highp float;
precision highp sampler3D;
uniform mat4 modelViewMatrix;
uniform mat4 projectionMatrix;
in vec3 vOrigin;
in vec3 vDirection;
out vec4 color;
uniform sampler3D map;
uniform float threshold;
uniform float steps;
vec2 hitBox( vec3 orig, vec3 dir ) {
const vec3 box_min = vec3( - 0.5 );
const vec3 box_max = vec3( 0.5 );
vec3 inv_dir = 1.0 / dir;
vec3 tmin_tmp = ( box_min - orig ) * inv_dir;
vec3 tmax_tmp = ( box_max - orig ) * inv_dir;
vec3 tmin = min( tmin_tmp, tmax_tmp );
vec3 tmax = max( tmin_tmp, tmax_tmp );
float t0 = max( tmin.x, max( tmin.y, tmin.z ) );
float t1 = min( tmax.x, min( tmax.y, tmax.z ) );
return vec2( t0, t1 );
}
float sample1( vec3 p ) {
return texture( map, p ).r;
}
vec4 sample2( vec3 p ) {
return texture( map, p );
}
#define epsilon .0001
vec3 normal( vec3 coord ) {
if ( coord.x < epsilon ) return vec3( 1.0, 0.0, 0.0 );
if ( coord.y < epsilon ) return vec3( 0.0, 1.0, 0.0 );
if ( coord.z < epsilon ) return vec3( 0.0, 0.0, 1.0 );
if ( coord.x > 1.0 - epsilon ) return vec3( - 1.0, 0.0, 0.0 );
if ( coord.y > 1.0 - epsilon ) return vec3( 0.0, - 1.0, 0.0 );
if ( coord.z > 1.0 - epsilon ) return vec3( 0.0, 0.0, - 1.0 );
float step = 0.01;
float x = sample1( coord + vec3( - step, 0.0, 0.0 ) ) - sample1( coord + vec3( step, 0.0, 0.0 ) );
float y = sample1( coord + vec3( 0.0, - step, 0.0 ) ) - sample1( coord + vec3( 0.0, step, 0.0 ) );
float z = sample1( coord + vec3( 0.0, 0.0, - step ) ) - sample1( coord + vec3( 0.0, 0.0, step ) );
return normalize( vec3( x, y, z ) );
}
vec4 BlendUnder(vec4 color, vec4 newColor)
{
color.rgb += (1.0 - color.a) * newColor.a * newColor.rgb;
color.a += (1.0 - color.a) * newColor.a;
return color;
}
void main(){
vec3 rayDir = normalize( vDirection );
vec2 bounds = hitBox( vOrigin, rayDir );
if ( bounds.x > bounds.y ) discard;
bounds.x = max( bounds.x, 0.0 );
vec3 p = vOrigin + bounds.x * rayDir;
vec3 inc = 1.0 / abs( rayDir );
float delta = min( inc.x, min( inc.y, inc.z ) );
delta /= steps;
for ( float t = bounds.x; t < bounds.y; t += delta ) {
vec4 samplerColor = sample2( p + 0.5 );
samplerColor.a *= .02;
color = BlendUnder(color, samplerColor);
p += rayDir * delta;
}
if ( color.a == 0.0 ) discard;
}
`;
const geometry = new THREE.BoxGeometry( 1, 1, 1 );
const material = new THREE.RawShaderMaterial( {
glslVersion: THREE.GLSL3,
uniforms: {
map: { value: texture },
cameraPos: { value: new THREE.Vector3() },
threshold: { value: 0. },
steps: { value: 200 }
},
vertexShader,
fragmentShader,
side: THREE.BackSide,
transparent:true
} );
mesh = new THREE.Mesh( geometry, material );
scene.add( mesh );
//
const parameters = { threshold: 0., steps: 200 };
function update() {
material.uniforms.threshold.value = parameters.threshold;
material.uniforms.steps.value = parameters.steps;
}
const gui = new GUI();
gui.add( parameters, 'steps', 0, 300, 1 ).onChange( update );
window.addEventListener( 'resize', onWindowResize );
}
function onWindowResize() {
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
renderer.setSize( window.innerWidth, window.innerHeight );
}
function animate() {
requestAnimationFrame( animate );
mesh.material.uniforms.cameraPos.value.copy( camera.position );
renderer.render( scene, camera );
}
</script>
</body>
