Threejs Shaders

Three.js 着色器

适用场景

• 需要在 Three.js 中编写自定义着色器逻辑。
• 任务涉及 ShaderMaterial、uniforms、GLSL、顶点变形或基于 fragment 的效果。
• 需要扩展内置材质无法满足的行为。

快速开始

import * as THREE from "three";

const material = new THREE.ShaderMaterial({
  uniforms: {
    time: { value: 0 },
    color: { value: new THREE.Color(0xff0000) },
  },
  vertexShader: `
    void main() {
      gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
    }
  `,
  fragmentShader: `
    uniform vec3 color;

    void main() {
      gl_FragColor = vec4(color, 1.0);
    }
  `,
});

// Update in animation loop
material.uniforms.time.value = clock.getElapsedTime();

ShaderMaterial 与 RawShaderMaterial 对比

ShaderMaterial

Three.js 提供内置 uniforms 和 attributes。

const material = new THREE.ShaderMaterial({
  vertexShader: `
    // Built-in uniforms available:
    // uniform mat4 modelMatrix;
    // uniform mat4 modelViewMatrix;
    // uniform mat4 projectionMatrix;
    // uniform mat4 viewMatrix;
    // uniform mat3 normalMatrix;
    // uniform vec3 cameraPosition;

    // Built-in attributes available:
    // attribute vec3 position;
    // attribute vec3 normal;
    // attribute vec2 uv;

    void main() {
      gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
    }
  `,
  fragmentShader: `
    void main() {
      gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
    }
  `,
});

RawShaderMaterial

完全自主控制——所有内容都需要自行定义。

const material = new THREE.RawShaderMaterial({
  uniforms: {
    projectionMatrix: { value: camera.projectionMatrix },
    modelViewMatrix: { value: new THREE.Matrix4() },
  },
  vertexShader: `
    precision highp float;

    attribute vec3 position;
    uniform mat4 projectionMatrix;
    uniform mat4 modelViewMatrix;

    void main() {
      gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
    }
  `,
  fragmentShader: `
    precision highp float;

    void main() {
      gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
    }
  `,
});

Uniforms

Uniform 类型

const material = new THREE.ShaderMaterial({
  uniforms: {
    // Numbers
    floatValue: { value: 1.5 },
    intValue: { value: 1 },

    // Vectors
    vec2Value: { value: new THREE.Vector2(1, 2) },
    vec3Value: { value: new THREE.Vector3(1, 2, 3) },
    vec4Value: { value: new THREE.Vector4(1, 2, 3, 4) },

    // Colors (converted to vec3)
    colorValue: { value: new THREE.Color(0xff0000) },

    // Matrices
    mat3Value: { value: new THREE.Matrix3() },
    mat4Value: { value: new THREE.Matrix4() },

    // Textures
    textureValue: { value: texture },
    cubeTextureValue: { value: cubeTexture },

    // Arrays
    floatArray: { value: [1.0, 2.0, 3.0] },
    vec3Array: {
      value: [new THREE.Vector3(1, 0, 0), new THREE.Vector3(0, 1, 0)],
    },
  },
});

GLSL 声明

// In shader
uniform float floatValue;
uniform int intValue;
uniform vec2 vec2Value;
uniform vec3 vec3Value;
uniform vec3 colorValue;    // Color becomes vec3
uniform vec4 vec4Value;
uniform mat3 mat3Value;
uniform mat4 mat4Value;
uniform sampler2D textureValue;
uniform samplerCube cubeTextureValue;
uniform float floatArray[3];
uniform vec3 vec3Array[2];

更新 Uniforms

// Direct assignment
material.uniforms.time.value = clock.getElapsedTime();

// Vector/Color updates
material.uniforms.position.value.set(x, y, z);
material.uniforms.color.value.setHSL(hue, 1, 0.5);

// Matrix updates
material.uniforms.matrix.value.copy(mesh.matrixWorld);

Varyings

将数据从 vertex shader 传递到 fragment shader。

const material = new THREE.ShaderMaterial({
  vertexShader: `
    varying vec2 vUv;
    varying vec3 vNormal;
    varying vec3 vPosition;

    void main() {
      vUv = uv;
      vNormal = normalize(normalMatrix * normal);
      vPosition = (modelViewMatrix * vec4(position, 1.0)).xyz;

      gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
    }
  `,
  fragmentShader: `
    varying vec2 vUv;
    varying vec3 vNormal;
    varying vec3 vPosition;

    void main() {
      // Use interpolated values
      gl_FragColor = vec4(vNormal * 0.5 + 0.5, 1.0);
    }
  `,
});

常用着色器模式

纹理采样

const material = new THREE.ShaderMaterial({
  uniforms: {
    map: { value: texture },
  },
  vertexShader: `
    varying vec2 vUv;

    void main() {
      vUv = uv;
      gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
    }
  `,
  fragmentShader: `
    uniform sampler2D map;
    varying vec2 vUv;

    void main() {
      vec4 texColor = texture2D(map, vUv);
      gl_FragColor = texColor;
    }
  `,
});

顶点位移

const material = new THREE.ShaderMaterial({
  uniforms: {
    time: { value: 0 },
    amplitude: { value: 0.5 },
  },
  vertexShader: `
    uniform float time;
    uniform float amplitude;

    void main() {
      vec3 pos = position;

      // Wave displacement
      pos.z += sin(pos.x * 5.0 + time) * amplitude;
      pos.z += sin(pos.y * 5.0 + time) * amplitude;

      gl_Position = projectionMatrix * modelViewMatrix * vec4(pos, 1.0);
    }
  `,
  fragmentShader: `
    void main() {
      gl_FragColor = vec4(0.5, 0.8, 1.0, 1.0);
    }
  `,
});

菲涅尔效果

const material = new THREE.ShaderMaterial({
  vertexShader: `
    varying vec3 vNormal;
    varying vec3 vWorldPosition;

    void main() {
      vNormal = normalize(normalMatrix * normal);
      vWorldPosition = (modelMatrix * vec4(position, 1.0)).xyz;
      gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
    }
  `,
  fragmentShader: `
    varying vec3 vNormal;
    varying vec3 vWorldPosition;

    void main() {
      // cameraPosition is auto-provided by ShaderMaterial
      vec3 viewDirection = normalize(cameraPosition - vWorldPosition);
      float fresnel = pow(1.0 - dot(viewDirection, vNormal), 3.0);

      vec3 baseColor = vec3(0.0, 0.0, 0.5);
      vec3 fresnelColor = vec3(0.5, 0.8, 1.0);

      gl_FragColor = vec4(mix(baseColor, fresnelColor, fresnel), 1.0);
    }
  `,
});

基于噪声的效果

// Simple noise function
float random(vec2 st) {
  return fract(sin(dot(st.xy, vec2(12.9898, 78.233))) * 43758.5453);
}

// Value noise
float noise(vec2 st) {
  vec2 i = floor(st);
  vec2 f = fract(st);

  float a = random(i);
  float b = random(i + vec2(1.0, 0.0));
  float c = random(i + vec2(0.0, 1.0));
  float d = random(i + vec2(1.0, 1.0));

  vec2 u = f * f * (3.0 - 2.0 * f);

  return mix(a, b, u.x) + (c - a) * u.y * (1.0 - u.x) + (d - b) * u.x * u.y;
}

// Usage
float n = noise(vUv * 10.0 + time);

渐变

// Linear gradient
vec3 color = mix(colorA, colorB, vUv.y);

// Radial gradient
float dist = distance(vUv, vec2(0.5));
vec3 color = mix(centerColor, edgeColor, dist * 2.0);

// Smooth gradient with custom curve
float t = smoothstep(0.0, 1.0, vUv.y);
vec3 color = mix(colorA, colorB, t);

边缘光

const material = new THREE.ShaderMaterial({
  vertexShader: `
    varying vec3 vNormal;
    varying vec3 vViewPosition;

    void main() {
      vNormal = normalize(normalMatrix * normal);
      vec4 mvPosition = modelViewMatrix * vec4(position, 1.0);
      vViewPosition = mvPosition.xyz;
      gl_Position = projectionMatrix * mvPosition;
    }
  `,
  fragmentShader: `
    varying vec3 vNormal;
    varying vec3 vViewPosition;

    void main() {
      vec3 viewDir = normalize(-vViewPosition);
      float rim = 1.0 - max(0.0, dot(viewDir, vNormal));
      rim = pow(rim, 4.0);

      vec3 baseColor = vec3(0.2, 0.2, 0.8);
      vec3 rimColor = vec3(1.0, 0.5, 0.0);

      gl_FragColor = vec4(baseColor + rimColor * rim, 1.0);
    }
  `,
});

溶解效果

uniform float progress;
uniform sampler2D noiseMap;

void main() {
  float noise = texture2D(noiseMap, vUv).r;

  if (noise < progress) {
    discard;
  }

  // Edge glow
  float edge = smoothstep(progress, progress + 0.1, noise);
  vec3 edgeColor = vec3(1.0, 0.5, 0.0);
  vec3 baseColor = vec3(0.5);

  gl_FragColor = vec4(mix(edgeColor, baseColor, edge), 1.0);
}

扩展内置材质

onBeforeCompile

修改已有材质的着色器。

const material = new THREE.MeshStandardMaterial({ color: 0x00ff00 });

material.onBeforeCompile = (shader) => {
  // Add custom uniform
  shader.uniforms.time = { value: 0 };

  // Store reference for updates
  material.userData.shader = shader;

  // Modify vertex shader
  shader.vertexShader = shader.vertexShader.replace(
    "#include <begin_vertex>",
    `
    #include <begin_vertex>
    transformed.y += sin(position.x * 10.0 + time) * 0.1;
    `,
  );

  // Add uniform declaration
  shader.vertexShader = "uniform float time;\n" + shader.vertexShader;
};

// Update in animation loop
if (material.userData.shader) {
  material.userData.shader.uniforms.time.value = clock.getElapsedTime();
}

常用注入点

// Vertex shader chunks
"#include <begin_vertex>"; // After position is calculated
"#include <project_vertex>"; // After gl_Position
"#include <beginnormal_vertex>"; // Normal calculation start

// Fragment shader chunks
"#include <color_fragment>"; // After diffuse color
"#include <output_fragment>"; // Final output
"#include <fog_fragment>"; // After fog applied

GLSL 内置函数

数学函数

// Basic
abs(x), sign(x), floor(x), ceil(x), fract(x)
mod(x, y), min(x, y), max(x, y), clamp(x, min, max)
mix(a, b, t), step(edge, x), smoothstep(edge0, edge1, x)

// Trigonometry
sin(x), cos(x), tan(x)
asin(x), acos(x), atan(y, x), atan(x)
radians(degrees), degrees(radians)

// Exponential
pow(x, y), exp(x), log(x), exp2(x), log2(x)
sqrt(x), inversesqrt(x)

向量函数

// Length and distance
length(v), distance(p0, p1), dot(x, y), cross(x, y)

// Normalization
normalize(v)

// Reflection and refraction
reflect(I, N), refract(I, N, eta)

// Component-wise
lessThan(x, y), lessThanEqual(x, y)
greaterThan(x, y), greaterThanEqual(x, y)
equal(x, y), notEqual(x, y)
any(bvec), all(bvec)

纹理函数

// GLSL 1.0 (default) - use texture2D/textureCube
texture2D(sampler, coord)
texture2D(sampler, coord, bias)
textureCube(sampler, coord)

// GLSL 3.0 (glslVersion: THREE.GLSL3) - use texture()
// texture(sampler, coord) replaces texture2D/textureCube
// Also use: out vec4 fragColor instead of gl_FragColor

// Texture size (GLSL 1.30+)
textureSize(sampler, lod)

常用材质属性

const material = new THREE.ShaderMaterial({
  uniforms: {
    /* ... */
  },
  vertexShader: "/* ... */",
  fragmentShader: "/* ... */",

  // Rendering
  transparent: true,
  opacity: 1.0,
  side: THREE.DoubleSide,
  depthTest: true,
  depthWrite: true,

  // Blending
  blending: THREE.NormalBlending,
  // AdditiveBlending, SubtractiveBlending, MultiplyBlending

  // Wireframe
  wireframe: false,
  wireframeLinewidth: 1, // Note: >1 has no effect on most platforms (WebGL limitation)

  // Extensions
  extensions: {
    derivatives: true, // For fwidth, dFdx, dFdy
    fragDepth: true, // gl_FragDepth
    drawBuffers: true, // Multiple render targets
    shaderTextureLOD: true, // texture2DLod
  },

  // GLSL version
  glslVersion: THREE.GLSL3, // For WebGL2 features
});

着色器包含

使用 Three.js Shader Chunks

import { ShaderChunk } from "three";

const fragmentShader = `
  ${ShaderChunk.common}
  ${ShaderChunk.packing}

  uniform sampler2D depthTexture;
  varying vec2 vUv;

  void main() {
    float depth = texture2D(depthTexture, vUv).r;
    float linearDepth = perspectiveDepthToViewZ(depth, 0.1, 1000.0);
    gl_FragColor = vec4(vec3(-linearDepth / 100.0), 1.0);
  }
`;

外部着色器文件

// With vite/webpack
import vertexShader from "./shaders/vertex.glsl";
import fragmentShader from "./shaders/fragment.glsl";

const material = new THREE.ShaderMaterial({
  vertexShader,
  fragmentShader,
});

实例化着色器

// Instanced attribute
const offsets = new Float32Array(instanceCount * 3);
// Fill offsets...
geometry.setAttribute("offset", new THREE.InstancedBufferAttribute(offsets, 3));

const material = new THREE.ShaderMaterial({
  vertexShader: `
    attribute vec3 offset;

    void main() {
      vec3 pos = position + offset;
      gl_Position = projectionMatrix * modelViewMatrix * vec4(pos, 1.0);
    }
  `,
  fragmentShader: `
    void main() {
      gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
    }
  `,
});

着色器调试

// Check for compile errors
material.onBeforeCompile = (shader) => {
  console.log("Vertex Shader:", shader.vertexShader);
  console.log("Fragment Shader:", shader.fragmentShader);
};

// Visual debugging
fragmentShader: `
  void main() {
    // Debug UV
    gl_FragColor = vec4(vUv, 0.0, 1.0);

    // Debug normals
    gl_FragColor = vec4(vNormal * 0.5 + 0.5, 1.0);

    // Debug position
    gl_FragColor = vec4(vPosition * 0.1 + 0.5, 1.0);
  }
`;

// Check WebGL errors
renderer.debug.checkShaderErrors = true;

性能优化建议

1. 减少 uniforms 数量：将相关值合并为向量
2. 避免条件分支：用 mix/step 替代 if/else
3. 预计算：尽可能将计算移到 JS 中完成
4. 善用纹理：复杂函数可用查找表（LUT）实现
5. 减少过度绘制：尽量避免透明对象

// Instead of:
if (value > 0.5) {
  color = colorA;
} else {
  color = colorB;
}

// Use:
color = mix(colorB, colorA, step(0.5, value));

TSL（Three.js Shading Language）— 未来方向

TSL 是 Three.js 的新一代着色器编写系统，同时支持 WebGL 和 WebGPU 渲染器。上面的 GLSL 模式仅适用于 WebGL，无法在 WebGPU 渲染器中使用。

TSL 快速开始

import { MeshStandardNodeMaterial } from "three/addons/nodes/Nodes.js";
import {
  uv, sin, timerLocal, vec4, color, positionLocal, normalLocal,
  float, mul, add
} from "three/addons/nodes/Nodes.js";

const material = new MeshStandardNodeMaterial();

// Animated color based on UV and time
const time = timerLocal();
material.colorNode = color(sin(add(uv().x, time)), uv().y, 0.5);

// Vertex displacement
material.positionNode = add(
  positionLocal,
  mul(normalLocal, sin(add(positionLocal.x, time)).mul(0.1))
);

TSL 与 GLSL 的核心差异

如何选择

• GLSL ShaderMaterial：已有 WebGL 项目、需要最大着色器控制力、移植已有着色器
• TSL NodeMaterial：新项目、需要 WebGPU 支持、跨渲染器兼容

相关技能

• threejs-materials — 内置材质类型
• threejs-postprocessing — 全屏着色器效果
• threejs-textures — 着色器中的纹理采样

限制条件

• 仅在任务明确匹配上述范围时使用此技能。
• 不可将输出视为环境特定验证、测试或专家评审的替代品。
• 缺少所需输入、权限、安全边界或成功标准时，应停下来请求澄清。