Custom Shader Material

Extend Three.js standard materials with your own shaders!

The demo is real, you can click it! It contains full code, too. 📦

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

Show Vanilla example

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

function Box() {
  const geometry = new THREE.BoxGeometry()
  const material = new CustomShaderMaterial({
    baseMaterial: THREE.MeshPhysicalMaterial,
    vertexShader: /* glsl */ ` ... `,
    fragmentShader: /* glsl */ ` ... `,
    silent: true, // Disables the default warning if true
    uniforms: {
      uTime: {
        value: 0,
      },
    },
    flatShading: true,
    color: 0xff00ff,
  })

  return new THREE.Mesh(geometry, material)
}

Show React example

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 */ ` ... `}
        fragmentShader={/* glsl */ ` ... `}
        {/*silent parameter to true disables the default warning if needed*/}
        silent
        uniforms={{
          uTime: {
            value: 0,
          },
        }}
        flatShading
        color={0xff00ff}
        // ...
      />
    </mesh>
  )
}

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
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	`vec3`	Direct equivalent of `gl_Position`.	Vertex Shader
csm_Normal	`vec3`	Custom vertex normals.	Vertex Shader
csm_PointSize	`float`	Custom gl_PointSize.	Vertex Shader	Only available in `PointsMaterial`
-	-	-	-	-
csm_DiffuseColor	`vec4`	Custom diffuse color.	Fragment Shader
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_Emissive	`vec3`	Custom emissive color.	Fragment Shader	Only available in `MeshPhysicalMaterial` and `MeshStandardMaterial`
csm_Roughness	`float`	Custom roughness.	Fragment Shader	Only available in `MeshPhysicalMaterial` and `MeshStandardMaterial`
csm_Metalness	`float`	Custom metalness.	Fragment Shader	Only available in `MeshPhysicalMaterial` and `MeshStandardMaterial`
csm_AO	`float`	Custom AO.	Fragment Shader	Only available in materials with an `aoMap`.
csm_Bump	`vec3`	Custom Bump.	Fragment Shader	Only available in materials with a `bumpMap`.

// gl_Position = projectionMatrix * modelViewPosition * position * vec3(2.0);
csm_Position = position * vec3(2.0);

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`
      }
   }}
})

Extending already extended materials

CSM allows you to extend other CSM instances or materials that already use onBeforeCompile to extend base functionality such as MeshTransmissionMaterial. It is as simple as passing a ref to that material in as the baseMaterial:

Show Vanilla example

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
  })

  // OR
  const material1 = new MeshTransmissionMaterial()
  const material2 = new CustomShaderMaterial({
    baseMaterial: material1,
    //...Any props
  })
}

Show React example

import CustomShaderMaterial from 'three-custom-shader-material'
import CustomShaderMaterialImpl from 'three-custom-shader-material/vanilla'

function Cube() {
  const [materialRef, setMaterialRef] = useState()
  // OR
  const materialRef = useMemo(
    () =>
      new CustomShaderMaterialImpl({
        baseMaterial: THREE.MeshPhysicalMaterial,
      }),
    []
  )

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

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

Gotchas

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.
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
}
```
The last injected shader will contain values set in all the shaders injected before it.

Performance

CSM is great for small overrides. Even though doable, if you find yourself lost in a patchMap, it's often simpler to just make a ShaderMaterial with the necessary #includes.

CSM has a non-negligible startup cost, i.e it does take more milliseconds than a plain ShaderMaterial to load. However, once loaded it is practically free. It also uses caching so reusing materials will not incur any extra cost. Couple important notes about performance:

Changing these props will rebuild the material
- baseMaterial
- fragmentShader
- vertexShader
- uniforms
- cacheKey
<meshPhysicalMaterial /> and <CSM baseMaterial={meshPhysicalMaterial}> are the same, and will use the same cached shader program. The default cache key is such:
```
hash(stripSpaces(fragmentShader) + stripSpaces(vertexShader) + serializedUniforms)
```
You can provide your own cache key function via the cacheKey prop.

Development

git clone https://github.com/FarazzShaikh/THREE-CustomShaderMaterial
cd THREE-CustomShaderMaterial
yarn
yarn dev

Will watch for changes in package/ and will hot-reload examples/debug.

License

MIT License

Copyright (c) 2021 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
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

supperjet/THREE-CustomShaderMaterial