three-instanced-uniforms-mesh
v0.50.3
Published
Extension to Three.js InstancedMesh supporting per-instance uniform values
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InstancedUniformsMesh
This package provides a InstancedUniformsMesh
class which extends Three.js's InstancedMesh
to allow its material's shader uniforms to be set individually per instance. It behaves just like InstancedMesh
but exposes a new method:
mesh.setUniformAt(uniformName, instanceIndex, value)
When you call setUniformAt
, the geometry and the material's shaders will be automatically upgraded behind the scenes to turn that uniform into an instanced buffer attribute, filling in the other indices with the uniform's default value. You can do this for any uniform of type float
, vec2
, vec3
, or vec4
. It works both for built-in Three.js materials and also for any custom ShaderMaterial.
For example, here is how you could set random emissive
and metalness
values for each instance using a MeshStandardMaterial
:
import { InstancedUniformsMesh } from 'three-instanced-uniforms-mesh'
const count = 100
const mesh = new InstancedUniformsMesh(
someGeometry,
new MeshStandardMaterial(),
count
)
const color = new Color()
for (let i = 0; i < count; i++) {
mesh.setMatrixAt(i, someMatrixValue)
mesh.setUniformAt('metalness', i, Math.random())
mesh.setUniformAt('emissive', i, color.set(Math.random() * 0xffffff))
}
While this is obviously useful for Three.js's built in materials, it really shines with custom shaders. Just declare any configurable parameters as uniforms in your custom shader, and then you can use that either on a single non-instanced Mesh
by setting the material's uniforms directly, or instance it using InstancedUniformsMesh
by calling setUniformAt
. Your shader doesn't need to change at all to support the instancing!
Note: Calling
setUniformAt
automatically marks the underlying buffer attributes for upload, so unlikesetMatrixAt
orsetColorAt
you don't need to setneedsUpdate
manually.
Value Types
The type of the value
argument should match the type of the uniform defined in the material's shader:
| For a uniform of type: | Pass a value of this type: |
|---------------------------|----------------------------------|
| float | Number |
| vec2 | THREE.Vector2
|
| vec3 | THREE.Vector3
or THREE.Color
|
| vec4 | THREE.Vector4
|
| mat3 (ThreeJS r132+ only) | THREE.Matrix3
|
| mat4 (ThreeJS r132+ only) | THREE.Matrix4
|
Resetting to defaults
If you have set instance-specific values for a given uniform but you want to revert all those to the single original uniform value, you can call:
mesh.unsetUniform(uniformName)