- Qt 6.6
- Qt 3D
- QML Types
- Qt3D.Render
- ShaderProgram
- Qt 6.6.1 Reference Documentation

# ShaderProgram QML Type

Encapsulates a Shader Program. More...

Import Statement: | import Qt3D.Render 2.6
Instantiates: | QShaderProgram

- List of all members, including inherited members

## Properties

- computeShaderCode : string
- computeShaderGraph : string
- format : enumeration
- fragmentShaderCode : string
- fragmentShaderGraph : string
- geometryShaderCode : string
- geometryShaderGraph : string
- log : string
- status : enumeration
- tessellationControlShaderCode : string
- tessellationControlShaderGraph : string
- tessellationEvaluationShaderCode : string
- tessellationEvaluationShaderGraph : string
- vertexShaderCode : string
- vertexShaderGraph : string

## Methods

- string loadSource(url sourceUrl)

## Detailed Description

ShaderProgram class encapsulates a shader program. A shader program consists of several different shaders, such as vertex and fragment shaders.

Qt3D will automatically populate a set of default uniforms if they are encountered during the shader instrospection phase.

Default Uniform | Associated Qt3D Parameter name | GLSL declaration
--- | --- | ---
ModelMatrix | modelMatrix | uniform mat4 modelMatrix;
ViewMatrix | viewMatrix | uniform mat4 viewMatrix;
ProjectionMatrix | projectionMatrix | uniform mat4 projectionMatrix;
ModelViewMatrix | modelView | uniform mat4 modelView;
ViewProjectionMatrix | viewProjectionMatrix | uniform mat4 viewProjectionMatrix;
ModelViewProjectionMatrix | modelViewProjection mvp | uniform mat4 modelViewProjection; uniform mat4 mvp;
InverseModelMatrix | inverseModelMatrix | uniform mat4 inverseModelMatrix;
InverseViewMatrix | inverseViewMatrix | uniform mat4 inverseViewMatrix;
InverseProjectionMatrix | inverseProjectionMatrix | uniform mat4 inverseProjectionMatrix;
InverseModelViewMatrix | inverseModelView | uniform mat4 inverseModelView;
InverseViewProjectionMatrix | inverseViewProjectionMatrix | uniform mat4 inverseViewProjectionMatrix;
InverseModelViewProjectionMatrix | inverseModelViewProjection | uniform mat4 inverseModelViewProjection;
ModelNormalMatrix | modelNormalMatrix | uniform mat3 modelNormalMatrix;
ModelViewNormalMatrix | modelViewNormal | uniform mat3 modelViewNormal;
ViewportMatrix | viewportMatrix | uniform mat4 viewportMatrix;
InverseViewportMatrix | inverseViewportMatrix | uniform mat4 inverseViewportMatrix;
AspectRatio (surface width / surface height) | aspectRatio | uniform float aspectRatio;
Exposure | exposure | uniform float exposure;
Gamma | gamma | uniform float gamma;
Time (in nano seconds) | time | uniform float time;
EyePosition | eyePosition | uniform vec3 eyePosition;
SkinningPalette | skinningPalette[0] | const int maxJoints = 100; uniform mat4 skinningPalette[maxJoints];

## RHI Support

When writing GLSL 450 shader code to use with Qt 3D's RHI backend, the default uniforms will be provided as 2 uniform buffer objects.

The binding locations for these is set to bindings 0 for RenderView uniforms and 1 for Command uniforms.

     #version 450 core

     layout(location = 0) in vec3 vertexPosition;

     layout(std140, binding = 0) uniform qt3d_render_view_uniforms {
       mat4 viewMatrix;
       mat4 projectionMatrix;
       mat4 uncorrectedProjectionMatrix;
       mat4 clipCorrectionMatrix;
       mat4 viewProjectionMatrix;
       mat4 inverseViewMatrix;
       mat4 inverseProjectionMatrix;
       mat4 inverseViewProjectionMatrix;
       mat4 viewportMatrix;
       mat4 inverseViewportMatrix;
       vec4 textureTransformMatrix;
       vec3 eyePosition;
       float aspectRatio;
       float gamma;
       float exposure;
       float time;
       float yUpInNDC;
       float yUpInFBO;
     };

     layout(std140, binding = 1) uniform qt3d_command_uniforms {
       mat4 modelMatrix;
       mat4 inverseModelMatrix;
       mat4 modelViewMatrix;
       mat3 modelNormalMatrix;
       mat4 inverseModelViewMatrix;
       mat4 modelViewProjection;
       mat4 inverseModelViewProjectionMatrix;
     };

     void main()
     {
         gl_Position = (projectionMatrix * viewMatrix * modelMatrix * vertexPosition);
     }

For user defined uniform buffer object, use binding starting at 2 or auto to let Qt 3D work out the binding automatically. Make sure to remain consistent between the different shader stages.

     #version 450 core

     layout(std140, binding = auto) uniform my_uniforms {
       vec4 myColor;
     };

     layout(location=0) out vec4 fragColor;

     void main()
     {
         fragColor = myColor;
     }

There is no change involved when it comes to feeding values to uniforms.

For the above example, setting myColor could be done with:

     Parameter { name: "myColor"; value: "blue" }

Textures still have to be defined as standalone uniforms.

     #version 450 core

     layout(binding=0) uniform sampler2D source;

     layout(location=0) out vec4 fragColor;

     void main()
     {
         fragColor = texture(source, vec2(0.5, 0.5));
     }

## Property Documentation

computeShaderCode : string

Holds the compute shader code used by this shader program.

computeShaderGraph : string

Holds the URL to the compute shader graph used by this shader program builder.

format : enumeration

Holds the format of the code provided on the ShaderProgram. The default is ShaderProgram.GLSL

fragmentShaderCode : string

Holds the fragment shader code used by this shader program.

fragmentShaderGraph : string

Holds the URL to the fragment shader graph used by this shader program builder.

geometryShaderCode : string

Holds the geometry shader code used by this shader program.

geometryShaderGraph : string

Holds the URL to the geometry shader graph used by this shader program builder.

[read-only] log : string

Holds the log of the current shader program. This is useful to diagnose a compilation failure of the shader program.

[read-only] status : enumeration

Holds the status of the current shader program.

tessellationControlShaderCode : string

Holds the tesselation control shader code used by this shader program.

tessellationControlShaderGraph : string

Holds the URL to the tesselation control shader graph used by this shader program builder.

tessellationEvaluationShaderCode : string

Holds the tesselation evaluation shader code used by this shader program.

tessellationEvaluationShaderGraph : string

Holds the URL to the tesselation evaluation shader graph used by this shader program builder.

vertexShaderCode : string

Holds the vertex shader code used by this shader program.

vertexShaderGraph : string

Holds the URL to the vertex shader graph used by this shader program builder.

## Method Documentation

string loadSource(url sourceUrl)

Returns the shader code loaded from sourceUrl.