User Guide Cancel

Shader API | Substance 3D Painter

Last updated on Jul 13, 2023

Substance 3D home
Home
Getting Started
1. Getting Started overview
2. Activation and licenses
3. System requirements
4. Project creation
5. Export
  1. Export overview
  2. Export window
  3. Export presets
    1. Export presets overview
    2. Predefined presets
    3. Creating export presets
6. Glossary
7. Performance
Interface
1. Assets
2. Substance 3D Assets
3. Color picker
4. Display settings
5. History
6. Layer stack
7. Main menu
8. Project configuration
9. Properties
10. Settings
11. Shader settings
  1. Shader settings overview
  2. Updating a shader
12. Texture Set
13. Toolbars
14. Viewport
15. Miscellaneous
Painting
1. Painting overview
2. Tool list
  1. Paint brush
  2. Eraser
  3. Projection
  4. Polygon fill
  5. Smudge tool
  6. Clone Tool
  7. Quick mask
  8. Path tool
3. Straight line
4. Lazy mouse
5. Symmetry
  1. Symmetry overview
  2. Mirror Symmetry
6. Fill projections
7. Presets
  1. Presets overview
  2. Creating and saving presets
  3. Creating particles presets
  4. Photoshop brush presets (ABR)
8. Dynamic strokes
9. Advanced channel painting
10. Vector graphic (.svg & .ai)
11. Text resource
Effects
1. Effects overview
2. Generator
3. Paint
4. Fill
5. Levels
6. Compare Mask
7. Filter
8. Anchor Point
Baking
Content
1. Creating custom effects
2. Importing assets
Features
1. Automatic UV Unwrapping
2. Physical size
3. Smart Materials and Masks
4. Subsurface Scattering
5. Dynamic Material Layering
6. UV Reprojection
7. UV Tiles
  1. UV Tiles overview
  2. Image Sequence
8. Color Management
9. Post Processing
10. Iray Renderer
11. Plugins
12. Sparse Virtual Textures
13. Custom Shaders
14. SpaceMouse® by 3Dconnexion
15. Universal Scene Description (USD)
16. Send to
Technical Support
1. Performance Guidelines
2. Configuring Pens and Tablets
3. Exporting the log file
4. Exporting a DXDiag
5. Technical issues
6. Workflow Issues
  1. Export Issues
    1. My exported opacity map is totally black
    2. Texture dilation or Padding
  2. Tools Issues
    1. Normal map looks incorrect when loaded in layer or tool properties
    2. Paint Tool bleeds on other UV islands
  3. Project Issues
  4. Library Issues
    1. Thumbnails in the shelf look incorrect
    2. Error when importing a Font
  5. Viewport Issues
    1. Mesh faces disappear when looking at them from behind
    2. Viewports and textures are blurry or lack sharpness
  6. Plugins Issues
    1. Substance Source plugin doesn't load
  7. License Issues
    1. Maintenance is expired dialog on startup
Pipeline and integration
1. Installation and preferences
2. Configuration
3. Resource management
Scripting and development
1. Scripts and plugins
  1. Creating a Javascript plugin
  2. Remote control with scripting
2. Shader API Reference
  1. Shader API overview
  2. Changelog - Shader API
  3. Libraries - Shader API
  4. Parameters - Shader API
  5. Shaders - Shader API
Release notes
1. Release notes overview
2. All Changes
3. Version 10.1
4. Version 10.0
5. Version 9.1
6. Old versions

Shader API

Substance Painter uses shaders to render materials in its realtime viewport. It is possible to write custom shaders to implement new behaviors or to simply make the viewport match other renderers.

Additional shaders for Substance Painter can be found on Substance Share.

Note:

The Shader API is also available directly from the application, by going into the menu Help > Documentation > Shader API.

Shader reference

Changelog

Full changelog file

Warm up

In Substance Painter, you can write your own shaders in GLSL. We allow you to write only a portion of the fragment shader, which is sometimes called a surface shader. Without further ado, let's introduce the "Hello world" Substance Painter surface shader:

void shade(V2F inputs) { 
  diffuseShadingOutput(vec3(1.0, 0.0, 1.0)); 
}

Now, if you save this snippet into a .glsl file and load it into Substance Painter by dropping it into your shelf's shader tab, you can now use it and see a beautiful uniform pink color on your mesh.

Surface shader

surface-shader.glsl

Engine provided data (or how do I access my channels?)

In Substance Painter, you can access rendering engine parameters (document's channels, additional textures, camera-related data and the like). Here is an exhaustive list of all engine provided parameters :

all-engine-params.glsl

Engine settings (or how do I specify rendering states?)

In some cases you may want to use a specific rendering configuration (culling, blending, sampling locality, and the like) for an effect. Some rendering states are exposed and can be set in the shader. Here is an exhaustive list of all exposed rendering states :

all-rendering-states-params.glsl

Custom tweaks (or how do I tweak my shader?)

It's usual to have custom tweaks in a shader. To do so in Substance Painter's shaders, we have introduced a way to specify custom tweaks. Here is an exhaustive list of all custom shader tweaks types :

all-custom-params.glsl

Embedded libraries

In order to avoid writing a lot of boilerplate code in all of your shaders, we created a small yet practical library of useful functions. Please note that you can't edit it nor create your own at the moment.

lib-alpha.glsl : contains opacity related helpers
lib-bayer.glsl : contains bayer matrix helpers
lib-defines.glsl : contains useful math constants
lib-emissive.glsl : contains emissive properties helpers
lib-env.glsl : contains environment map related helpers
lib-normal.glsl : contains normal map related helpers (and height-map generated normal map)
lib-pbr.glsl : contains physically based rendering helpers
lib-pbr-aniso.glsl : contains anisotropic physically based rendering helpers
lib-pom.glsl : contains parallax occlusion mapping helpers
lib-random.glsl : contains random utilities (low discrepancy sequences)
lib-sampler.glsl : contains channel getters helpers
lib-sparse.glsl : contains safe sparse texture sampling helpers
lib-sss.glsl : contains subsurface scattering helpers
lib-utils.glsl : contains color utility functions (sRGB conversions, tone mapping)
lib-vectors.glsl : contains common vectors helpers

Metadata

You can declare additional non required information to give some hint to the rendering system. Here is the syntax:

//: metadata { 
//:   "key1":"value1", 
//:   "key2":"value2" 
//: }

Supported keys are:

custom-ui: Replace the standard shader parameters user interface with a custom view written as a QML module (see scripting documentation). The path can be absolute or relative to one of your shelf custom-ui folder.
mdl: define the Iray mdl material to use with the shader. The path syntax is as follow: mdl::folder1::folder2::mdl_filename::material_name where folder1::folder2::mdl_filename is the path inside one of your shelf mdl folder to a mdl file and ::material_name is the name of a material declared inside this mdl file. (ex: "mdl" : "mdl::alg::materials::physically_metallic_roughness::physically_metallic_roughness")

Example shaders (yeah, finally!)

To get a taste of what looks like a real shader, here are a few sample shader, ordered by increasing complexity:

pixelated.glsl : a pixelating shader
toon.glsl : a toon shader
pbr-metal-rough.glsl : the default PBR shader embedded in Substance Painter

Dynamic material layering

The Dynamic Material Layering is a specific workflow where materials are mixed together inside a shader and let the user dynamically edit blending masks in Substance Painter. To enable this workflow, there are two new functionalities:

declare editable stacks from a shader definition: layering_declare_stacks.glsl
bind materials as shader parameters: layering_bind_materials.glsl

Get help faster and easier

New user?