Custom Shader Material

Since 2.0.0

Shader selection, reload, and parameters generated from the Core Shader JSON.

Custom Shader Material loads Minecraft Core Shader JSON, VSH, and FSH files directly. It is not a deprecated predecessor to Shader Graph. Use it to port GLSL, add a geometry stage, or implement an algorithm that graph nodes do not cover.

The subject is split into three pages:

• This page: create the material, select a shader, and configure parameters in the Inspector.
• Hand-written Core Shaders and ExtendedShader: a complete JSON/VSH/FSH material.
• Built-in Uniform and Sampler Reference: exact names, types, sources, and limitations.

For input layouts and particle data, also see Vertex Formats and GPU Instancing and Additional GPU Data.

Resource Layout

assets/<namespace>/shaders/core/<name>.json
assets/<namespace>/shaders/core/<vertex>.vsh
assets/<namespace>/shaders/core/<fragment>.fsh
assets/<namespace>/shaders/include/<library>.glsl   # optional

The material's shader ID is <namespace>:<name>, without assets/, shaders/core/, or .json:

assets/wiki/shaders/core/dissolve_particle.json
                         ↓
wiki:dissolve_particle

Development assets can live in an enabled resource pack or a mod JAR. When using the editor's file picker, the file must still be below assets/<namespace>/shaders/core/ so Photon can derive the shader ID.

Use It in the Editor

1. Add Custom Shader Material under an emitter's Renderer > Materials.
2. Click Select Shader and choose the Core Shader JSON, or enter its shader ID.
3. After a successful compile, expand Shader Settings.
4. Assign custom textures, numbers, vectors, and colors.
5. After editing JSON/VSH/FSH, click Reload Shader.

A red error message in the preview means the shader did not compile. Photon caches this failure so it does not create another failed GL program every frame; fix the error and reload explicitly.

How the Inspector Finds Parameters

LDShaderHolder reads the JSON declarations and creates controls for entries that are not built in.

JSON declaration	Inspector control
Custom sampler such as Texture or NoiseTexture	texture picker and preview
int, count 1–4	integer or integer vector
float, count 1–4	float or float vector
vec3 name containing color or rgb	RGB color
vec4 name containing color or rgba	RGBA color
vec4 name containing hdr or emission	HDR color and intensity

Names therefore affect the editor. TintColor gets a color control; Direction gets a vector control.

Reserved names

Every sampler beginning with Sampler and every uniform beginning with U_ is considered built in and is hidden from Shader Settings. Use only names listed in the reference; do not use either prefix for custom parameters.

Parameter values are saved with the material. On reload, Photon retains values whose names and types still match. Renamed or removed entries must be configured again.

Shader Graph or Hand-written Shader?

Requirement	Choose
General material logic and reuse across renderers	Shader Graph
Existing GLSL/Core Shader	Custom Shader Material
Geometry shader	Custom Shader Material
Automatic GPU-channel declaration	Shader Graph
Manual attributes, varyings, and GLSL includes	Custom Shader Material

A hand-written shader does not infer the Additional GPU Data it needs. Enable each channel in the emitter and check whether its render path supports that channel.

Next

Build the three-file example in Hand-written Core Shaders and ExtendedShader. Keep the Built-in Uniform and Sampler Reference open while authoring.