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Three.js 3d热力图-体积版教程

news 2026/7/2 16:28:29

3d热力图-体积版 ·volumeHeatmap· ▶ 在线运行案例

案例合集：三维可视化功能案例（threehub.cn）
开源仓库github地址：https://github.com/z2586300277/three-cesium-examples
400个案例代码:网盘链接

你将学到什么

ShaderMaterial 自定义着色器实现核心视觉效果
OrbitControls 相机轨道交互
Canvas 动态纹理贴图
Raycaster 鼠标拾取与交互
CSS2D/3D 标签 DOM 叠加
requestAnimationFrame渲染循环与resize自适应

效果说明

本案例演示3d热力图-体积版效果：创建一个取色带，用 Canvas 2D 绘制内容并实时映射为 Three.js 纹理；核心用到 ShaderMaterial、OrbitControls、Canvas。建议先打开文首在线案例查看动态画面，再对照下方源码逐步理解。

核心概念

Scene / Camera / WebGLRenderer构成最小渲染闭环；大场景可开logarithmicDepthBuffer缓解 Z-fighting。
ShaderMaterial通过uniforms+ 自定义 GLSL 控制逐像素/逐点效果；透明粒子常配合depthTest: false。
OrbitControls提供轨道旋转/缩放；开启enableDamping后需在 animate 中controls.update()。
CanvasTexture每帧或按需把 2D Canvas 内容上传 GPU，适合动态文字、图表、视频帧贴图。
Raycaster将屏幕坐标转为射线，与场景求交得到世界坐标，常用于绘制/拾取。

实现步骤

搭建灯光与环境（如有）
requestAnimationFrame 循环 update + render

代码要点

import * as THREE from 'three';import Stats from 'three/examples/jsm/libs/stats.module.js'; import {OrbitControls} from 'three/examples/jsm/controls/OrbitControls.js' import {GUI} from "three/addons/libs/lil-gui.module.min.js" import { CSS2DRenderer, CSS2DObject } from 'three/examples/jsm/renderers/CSS2DRenderer.js' console.log('Three.js 版本:', THREE.REVISION); const gui = new GUI()
// 初始化场景、相机、渲染器 const scene = new THREE.Scene(); const camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 10000); camera.position.set(50, 100, 100) camera.lookAt(0, 0, 0) scene.add(camera); const renderer = new THREE.WebGLRenderer({ antialias: true, alpha: true, logarithmicDepthBuffer: true }); renderer.outputColorSpace = 'srgb' renderer.setSize(window.innerWidth, window.innerHeight); renderer.setClearColor(0x000000); document.body.appendChild(renderer.domElement);
const cssRender = new CSS2DRenderer() cssRender.setSize(window.innerWidth, window.innerHeight) cssRender.domElement.style.position = "absolute" cssRender.domElement.style.top = "0" cssRender.domElement.style.zIndex = "3" cssRender.domElement.style.pointerEvents = "none" document.body.appendChild(cssRender.domElement)
// 添加性能监控 const stats = new Stats(); document.body.appendChild(stats.dom); // 初始化控制器 const controls = new OrbitControls(camera, renderer.domElement); controls.enableDamping = true;
/**
创建一个取色带
*/ function initPalette() { let canvas = document.createElement("canvas") canvas.width = 256 canvas.height = 1 let ctx = canvas.getContext("2d") let lgrd = ctx.createLinearGradient(0, 0, 256, 1) let gradient = { "0": "rgba(0,0,255,0.1)", "0.1": "rgba(0,0,255,1)", "0.3": "rgba(0,255,0,1)", "0.75": "rgba(255,255,0,1)", "1": "rgba(255,0,0,1.0)", } for (let key in gradient) { lgrd.addColorStop(parseFloat(key), gradient[key]) } ctx.fillStyle = lgrd ctx.fillRect(0, 0, 256, 1) return canvas }const texture = new THREE.CanvasTexture(initPalette())
// 生成模拟热力数据 (64x64x64) const size = 64 const data = new Float32Array(sizesizesize) const cutoffHeight = size * 0.8 // 80%高度处 // 存储热力图数据用于查询 const heatmapData = { size: 64, data, } for (let z = 0; z < size; z++) { for (let y = 0; y < size; y++) { for (let x = 0; x < size; x++) { // 1. 垂直方向渐变（底部1.0 -> 80%高度0.0） const verticalFactor = Math.max(0, 1 - y / cutoffHeight)
// 2. 水平方向渐变（左侧0.0 -> 右侧1.0） const horizontalFactor = x / size
// 3. 组合两种渐变（相乘得到最终值） data[zsizesize + ysize + x] = verticalFactorhorizontalFactor
} } } // 创建3D纹理时添加配置 const heatMapTexture = new THREE.Data3DTexture(data, size, size, size) heatMapTexture.format = THREE.RedFormat heatMapTexture.type = THREE.FloatType heatMapTexture.wrapS = THREE.ClampToEdgeWrapping heatMapTexture.wrapT = THREE.ClampToEdgeWrapping heatMapTexture.wrapR = THREE.ClampToEdgeWrapping heatMapTexture.needsUpdate = true heatMapTexture.updateMatrix() // 关键！ const material = new THREE.ShaderMaterial({ uniforms: { uVolume: { value: heatMapTexture }, uColorMap: { value: texture }, // 传入取色带纹理 uResolution: { value: new THREE.Vector3(size, size, size) }, uCursorPos: { value: new THREE.Vector3(-1000, -1000, -1000) }, // 初始值设为屏幕外 uCursorRadius: { value: 2.0 }, // 高亮区域半径 uThreshold: { value: 0.01 }, // 显示阈值 uSteps: { value: 128 }, // 光线步进次数 }, vertexShader:varying vec3 vWorldPosition; varying vec3 vLocalPosition; // 新增局部坐标传递 void main() { vWorldPosition = (modelMatrix * vec4(position, 1.0)).xyz; vLocalPosition = position; // 传递局部坐标（-size/2到size/2） gl_Position = projectionMatrixmodelViewMatrixvec4(position, 1.0); }, fragmentShader:uniform sampler3D uVolume; uniform vec3 uResolution; uniform float uThreshold; uniform sampler2D uColorMap; // 取色带纹理 uniform int uSteps; varying vec3 vWorldPosition; varying vec3 vLocalPosition;
uniform vec3 uCursorPos; uniform float uCursorRadius;
// 热力值转颜色（保持不变） vec3 heatmap(float value) { return texture2D(uColorMap, vec2(clamp(value, 0.0, 1.0), 0.5)).rgb; }
void main() { // 1. 计算光线起点（相机位置）和方向（指向当前像素） vec3 rayOrigin = cameraPosition; vec3 rayDir = normalize(vWorldPosition - cameraPosition);
// 2. 计算光线与立方体的交点（避免从内部开始） vec3 boxMin = -uResolution * 0.5; vec3 boxMax = uResolution * 0.5; vec3 tMin = (boxMin - rayOrigin) / rayDir; vec3 tMax = (boxMax - rayOrigin) / rayDir; vec3 t1 = min(tMin, tMax); vec3 t2 = max(tMin, tMax); float tNear = max(max(t1.x, t1.y), t1.z); float tFar = min(min(t2.x, t2.y), t2.z);
// 3. 调整起点到最近的交点 rayOrigin += rayDir * tNear;
// 4. 光线步进参数 float stepSize = (tFar - tNear) / float(uSteps); vec4 color = vec4(0.0);
// 5. 光线步进循环 for (int i = 0; i < uSteps; i++) { vec3 samplePos = rayOrigin + rayDirfloat(i)stepSize; vec3 uv = (samplePos / uResolution) + 0.5; // 转换到纹理坐标
if (any(lessThan(uv, vec3(0.0))) || any(greaterThan(uv, vec3(1.0)))) continue;
float density = texture(uVolume, uv).r; if (density < uThreshold) continue;
vec3 heatColor = heatmap(density); float alpha = density * 0.5; // 提高透明度系数
// 从前到后混合 color.rgb += (1.0 - color.a)alphaheatColor; color.a += (1.0 - color.a) * alpha;
if (color.a > 0.95) break; }
// 添加光标交互高亮 float dist = distance(vLocalPosition, uCursorPos); if (dist < uCursorRadius) { color.rgb = vec3(1.0, 0.0, 0.0); }gl_FragColor = color; gl_FragColor.a = clamp(color.a, 0.0, 1.0)*0.5; // 确保透明度在0到1之间 }, side: THREE.BackSide, // 从内部渲染 transparent: true, alphaTest: 0.01, // 避免低透明度片元被丢弃 })
gui.add(material.uniforms.uThreshold, "value", 0, 1).name("阈值") gui.add(material.uniforms.uSteps, "value", 16, 1000).name("步进次数")
const geometry = new THREE.BoxGeometry(size, size, size) const mesh = new THREE.Mesh(geometry, material)
// 帧循环 function animate() { requestAnimationFrame(animate) renderer.render(scene, camera); cssRender.render(scene, camera); stats.update(); controls.update(); }
animate();
const raycaster = new THREE.Raycaster() const mouse = new THREE.Vector2() scene.add(mesh) const element = document.createElement("div") element.style.position = 'absolute'; element.style.width='200px' element.style.height='44px' element.style.textAlign = 'center' element.style.border = '1px solid #ffffff' element.style.lineHeight = '44px' element.style.color='#ffffff' const label = new CSS2DObject(element) label.position.set(0, 0, 0) scene.add(label)
function onMouseMove(event) { // 转换鼠标坐标到标准化设备坐标 [-1, 1] mouse.x = (event.clientX / window.innerWidth) * 2 - 1 mouse.y = -(event.clientY / window.innerHeight) * 2 + 1
checkIntersection() }
function checkIntersection() { // 更新射线 raycaster.setFromCamera(mouse, camera)
// 检测与热力立方体的相交 const intersects = raycaster.intersectObject(mesh)
if (intersects.length > 0) { const point = intersects[0].point
mesh.worldToLocal(point) material.uniforms.uCursorPos.value.copy(point) // 转换世界坐标到纹理坐标 [0,1] const uv = new THREE.Vector3() .copy(point) .add(new THREE.Vector3(size / 2, size / 2, size / 2)) // 补偿立方体中心偏移 .divideScalar(size)
// 获取精确数据值 const value = getDataAtUV(uv)
label.position.set(point.x, point.y+15, point.z) // 提示标签位置 element.innerText =${value}label.visible = true // // 显示数据（示例：控制台输出+屏幕提示） // console.log( //坐标: (${point.x.toFixed(2)}, ${point.y.toFixed(2)}, ${point.z.toFixed(2)}) 热力值: ${value?.toFixed(4)}// ) } else { // 鼠标未指向时重置位置（隐藏高亮） material.uniforms.uCursorPos.value.set(-1000, -1000, -1000) label.visible = false } // 标记需要更新uniforms material.uniformsNeedUpdate = true }
function getDataAtUV(uv) { // 计算数据索引 const x = Math.floor(uv.x * (heatmapData.size - 1)) const y = Math.floor(uv.y * (heatmapData.size - 1)) const z = Math.floor(uv.z * (heatmapData.size - 1))
const index = zsizesize + y * size + x return heatmapData.data[index] }
// 窗口大小调整 window.addEventListener("mousemove", onMouseMove) window.addEventListener('resize', onWindowResize, false); function onWindowResize() { camera.aspect = window.innerWidth / window.innerHeight; camera.updateProjectionMatrix(); renderer.setSize(window.innerWidth, window.innerHeight); cssRender.setSize(window.innerWidth, window.innerHeight); }