Creating Effects

Effects are json-based layers that specify a shader and expose its parameters. Material Painter ships with some useful effects by default, for example blur, hsv adjust and invert.

Structure of an Effect

This is the structure of the Scalar layer:

{
        "name": "Scalar",
        "properties" : [
                {
                        "name": "value",
                        "type": "float",
                        "range": [0, 1],
                        "default": 0.5
                }
        ],
        "blends": true,
        "in_context_menu": true,
        "shader": "return vec4({value}, {value}, {value}, 1.0);"
}

The name is how the effect will be called in Material Painter. The properties array holds the properties that can be used in the shader and are exposed in the editor. If in_context_menu is true, the effect will appear when right clicking in the Layer Stack.

The Shader

The shader property holds the shader that is used to compose the final material. It should return a vec4.

Information about Godot’s shader language can be found in the Godot Shader Reference.

Properties

There are properties for each shader uniform type. The type of a property is specified in the type value.

Here are the available types and their unique settings:

color

float and int

range:An array with two numbers, for example [0.0, 5.5]. default:The default value, for example 1.0.

enum

options:An array of values, for example ["r", "g", "b"]. default:An element of the options array that is the default value.

Using Properties in the Shader

By default, every property will be added to the shader as a uniform and can be used in the shader with {property_name}. If shader_param is set to false, the property will not be added as a uniform, and can be used in the shader directly. This is used in the Isolate Channel layer to specify if the red, green or blue channel should be isolated.

Blending and modifying

Layers can either return a value that is blended with the previous layer, like a Scalar or a Color layer. This can be enabled by setting blends to true. By default they modify the previous layer, like Blur or HSVAdjust. You can use {previous}(uv) to refer to the previous result; {previous} is the function of the previous layer, so you can pass any uv coordinates you want. This is used in the Blur layer.

Using the Effect

Like any asset, you can add it to your global library by dropping the effect file into the Asset Browser. It will be stored in user://assets/effects. To add an effect to your project library, you can put it in the asset/effects folder alongside your project file.