Custom Shader Material (CSM) lets you extend Three.js' material library with your own Vertex and Fragment shaders. It Supports both Vanilla and React!

import CustomShaderMaterial from "three-custom-shader-material/vanilla";

function Box() {
  const geometry = new THREE.BoxGeometry();
  const material = new CustomShaderMaterial({
    baseMaterial: THREE.MeshPhysicalMaterial,
    vertexShader: /* glsl */ ` ... `, // Your vertex Shader
    fragmentShader: /* glsl */ ` ... `, // Your fragment Shader
    // Your Uniforms
    uniforms: {
      uTime: { value: 0 },
      ...
    },
    // Base material properties
    flatShading: true,
    color: 0xff00ff,
    ...
  });

  return new THREE.Mesh(geometry, material);
}

import CustomShaderMaterial from 'three-custom-shader-material'

function Cube() {
  const materialRef = useRef()

  useFrame((state) => {
    if (materialRef.current) {
      materialRef.current.uniforms.uTime.value = state.clock.elapsedTime
    }
  })

  return (
    <mesh>
      <boxGeometry />
      <CustomShaderMaterial
        ref={materialRef}
        baseMaterial={THREE.MeshPhysicalMaterial}
        vertexShader={/* glsl */ ` ... `} // Your vertex Shader
        fragmentShader={/* glsl */ ` ... `} // Your fragment Shader
        // Your Uniforms
        uniforms={{
          uTime: { value: 0 },
          ...
        }}
        // Base material properties
        flatShading
        color={0xff00ff}
        ...
      />
    </mesh>
  )
}

Moved to Cientos' Docs

Installation

npm install three-custom-shader-material
yarn add three-custom-shader-material

Output Variables

CSM provides the following output variables, all of them are optional but you MUST use these variables like you would use standard GLSL output variables to see results.

| Variable | Type | Description | Available In | Notes | | --------------------------------- | ------- | ---------------------------------------------------------- | ----------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Vertex Shader | - | - | - | - | | csm_Position | vec3 | Custom vertex position. | Vertex Shader | csm_Position will be projected furthur down the line. Thus, no projection is needed here. | | csm_PositionRaw | vec4 | Direct equivalent of gl_Position. | Vertex Shader | | | csm_Normal | vec3 | Custom vertex normals. | Vertex Shader | | csm_PointSize | float | Direct equivalent of gl_PointSize. | Vertex Shader | Only available in PointsMaterial | | Fragmet Shader | - | - | - | - | | csm_DiffuseColor | vec4 | Custom diffuse color. | Fragment Shader | Base material's shading will be applied to this color. | | csm_FragColor | vec4 | Direct equivalent of gl_FragColor. | Fragment Shader | csm_FragColor will override any shading applied by a base material. To preserve shading and other effects like roughness and metalness, use csm_DiffuseColor | | csm_Roughness | float | Custom roughness. | Fragment Shader | Only available in materials with an roughnessMap. | | csm_Metalness | float | Custom metalness. | Fragment Shader | Only available in materials with an metalnessMap. | | csm_AO | float | Custom AO. | Fragment Shader | Only available in materials with an aoMap. | | csm_Bump | vec3 | Custom bump as perturbation to fragment normals. | Fragment Shader | Only available in materials with a bumpMap. | | csm_Clearcoat | float | Custom clearcoat factor. | Fragment Shader | Only available in materials with a clearcoat. | | csm_ClearcoatRoughness | float | Custom clearcoat roughenss factor. | Fragment Shader | Only available in materials with a clearcoat. | | csm_ClearcoatNormal | vec3 | Custom clearcoat normal. | Fragment Shader | Only available in materials with a clearcoat. | | csm_Transmission | float | Custom transmission factor. | Fragment Shader | Only available in materials with a transmission. | | csm_Thickness | float | Custom transmission thickness. | Fragment Shader | Only available in materials with a transmission. | | csm_Iridescence | float | Custom iridescence factor. | Fragment Shader | Only available in materials with a iridescence. | | csm_Emissive | vec3 | Custom emissive color. | Fragment Shader | Only available in materials with a emissive. | | csm_FragNormal | vec3 | Custom fragment normal. | Only available in materials with a normalMap. | | Fragmet Shader (Special) | - | - | - | - | | csm_DepthAlpha | float | Custom alpha for MeshDepthMaterial. | Fragment Shader | Useful for controlling customDepthMaterial with same shader as the shader material. | | csm_UnlitFac | float | Custom mix between csm_DiffuseColor and csm_FragColor. | Fragment Shader | Can be used to mix lit and unlit materials. Set to 1.0 by default if csm_FragColor is found in shader string. |

Typing

CSM infers prop types based on the baseMaterial prop. However, if this does not work for what ever reason, you can pass your base material type as a generic to CustomShaderMaterial<T>.

// Vanilla
const material = new CustomShaderMaterial<THREE.MeshPhysicalMaterial>({
  baseMaterial: THREE.MeshPhysicalMaterial,
  //...Any props
});

// React
<CustomShaderMaterial<THREE.MeshPhysicalMaterial>
  baseMaterial={THREE.MeshPhysicalMaterial}
  //...Any props

Custom overrides

You can define any custom overrides you'd like using the patchMap prop. The prop is used as shown below.

const material = new CustomShaderMaterial({
   baseMaterial: THREE.MeshPhysicalMaterial,
   vertexShader: ` ... `,
   fragmentShader: ... `,
   uniforms: {...},
   patchMap={{
      "<KEYWORD>": {        // The keyword you will assign to in your custom shader
        "TO_REPLACE":       // The chunk you'd like to replace.
          "REPLACED_WITH"   // The chunk you'd like put in place of `TO_REPLACE`
      }
   }}
})

Note: If <KEYWORD> is not found in shader string, the patch map will not be applied. To ALWAYS apply a patch map, use the special keyword - * (star).

patchMap={{
  "*": { "TO_REPLACE": "REPLACED_WITH" }
}}

Extending already extended materials

CSM allows you to extend other CSM instances. Values set in the first shader will affect the next.

Note: Extending of other materials that use onBeforeCompile may or may not work depending on if the default #includes are mangled.

import CustomShaderMaterial from "three-custom-shader-material/vanilla";

function Box() {
  const material1 = new CustomShaderMaterial({
    baseMaterial: THREE.MeshPhysicalMaterial,
    //...Any props
  });
  const material2 = new CustomShaderMaterial({
    baseMaterial: material1,
    //...Any props
  });
}

import CustomShaderMaterial from "three-custom-shader-material";
import CustomShaderMaterialImpl from "three-custom-shader-material/vanilla";

function Cube() {
  const [materialRef, setMaterialRef] = useState();

  return (
    <>
      <CustomShaderMaterial
        ref={setMaterialRef}
        baseMaterial={THREE.MeshPhysicalMaterial}
        //...Any props
      />

      {materialRef && (
        <CustomShaderMaterial
          baseMaterial={materialRef}
          //...Any props
        />
      )}
    </>
  );
}

Gotchas

• csm_Position MUST be a non-projected vector. i.e., no need to multiply projectionMatrix or modelViewPosition with it. If you require projection, use csm_PositionRaw.

• Instancing must be handled manually when using csm_PositionRaw by multiplying in instanceMatrix into your projection math.

• When extending already extended material, variables, uniforms, attributes, varyings and functions are NOT scoped to the material they are defined in. Thus, you WILL get redefinition errors if you do not manually scope these identifiers.

• Extending of other materials that use onBeforeCompile may or may not work depending on if the default #includes are mangled.

• When using an instance of CSM as the baseMaterial, or chining multiple CSM instances, or when extending any material that uses onBeforeCompile the injection order is as follows:

  void main() {
    // shader A
    // shader B
    // shader C
    // shader D
  
    // original shader
  }

  Where A was the first in the chain.

• Cache key calculation takes into account base material's cache key. Useful for propagating changes across multiple chained CSM instances.

• If you find yourself lost in a patchMap, it's often simpler to just make a ShaderMaterial with the necessary #includes.

Performance

With v6, CSM's initialization cost is now negligible 🥳 Still, a couple important notes about performance:

• Changing these props will rebuild the material

  • baseMaterial
  • fragmentShader
  • vertexShader
  • uniforms
  • cacheKey

• CSM uses ThreeJS's default shader program caching system. Materials with the same cache key, will use the the same shader program.

• <meshPhysicalMaterial /> and <CSM baseMaterial={meshPhysicalMaterial}> are the same, and will use the same cached shader program. The default cache key is such:

  (cacheKey?.() || hash((vertexShader || "") + (fragmentShader || ""))) +
    baseMaterialCacheKey?.();

  You can provide your own cache key function via the cacheKey prop.

Note: CSM will only rebuild if the reference to the above props change, for example, in React, doing uniforms={{...}} means that the uniforms object is unstable, i.e. it is re-created, with a new reference every render. Instead, condsider memoizing the uniforms prop const uniforms = useMemo(() -> ({...}));. The uniforms object will then have the same refrence on every render.

If the uniforms are memoized, changing their value by doing uniforms.foo.value = ... will not cause CSM to rebuild, as the refrence of uniforms does not change.

License

MIT License

Copyright (c) 2024 Faraz Shaikh

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
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copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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