- Qt 6.4
- Qt 3D
- C++ Classes
- Qt3DRender
- QShaderProgram
- Qt 6.4.3 Reference Documentation

# QShaderProgram Class

class Qt3DRender::QShaderProgram

Encapsulates a Shader Program. More...

Header: | #include <QShaderProgram>
CMake: | find_package(Qt6 REQUIRED COMPONENTS 3drender) target_link_libraries(mytarget PRIVATE Qt6::3drender)
qmake: | QT += 3drender
Since: | Qt 5.5
Instantiated By: | ShaderProgram
Inherits: | Qt3DCore::QNode

- List of all members, including inherited members

## Public Types

enum | Format { GLSL, SPIRV }
enum | ShaderType { Vertex, Fragment, TessellationControl, TessellationEvaluation, Geometry, Compute }
enum | Status { NotReady, Ready, Error }

## Properties

computeShaderCode : QByteArray format : Format fragmentShaderCode : QByteArray geometryShaderCode : QByteArray log : const QString | status : const Status tessellationControlShaderCode : QByteArray tessellationEvaluationShaderCode : QByteArray vertexShaderCode : QByteArray

## Public Functions

QByteArray | computeShaderCode() const
Qt3DRender::QShaderProgram::Format | format() const
QByteArray | fragmentShaderCode() const
QByteArray | geometryShaderCode() const
QString | log() const
void | setFormat(Qt3DRender::QShaderProgram::Format format)
void | setShaderCode(Qt3DRender::QShaderProgram::ShaderType type, const QByteArray &shaderCode)
QByteArray | shaderCode(Qt3DRender::QShaderProgram::ShaderType type) const
Qt3DRender::QShaderProgram::Status | status() const
QByteArray | tessellationControlShaderCode() const
QByteArray | tessellationEvaluationShaderCode() const
QByteArray | vertexShaderCode() const

## Public Slots

void | setComputeShaderCode(const QByteArray &computeShaderCode)
void | setFragmentShaderCode(const QByteArray &fragmentShaderCode)
void | setGeometryShaderCode(const QByteArray &geometryShaderCode)
void | setTessellationControlShaderCode(const QByteArray &tessellationControlShaderCode)
void | setTessellationEvaluationShaderCode(const QByteArray &tessellationEvaluationShaderCode)
void | setVertexShaderCode(const QByteArray &vertexShaderCode)

## Signals

void | computeShaderCodeChanged(const QByteArray &computeShaderCode)
void | formatChanged(Qt3DRender::QShaderProgram::Format format)
void | fragmentShaderCodeChanged(const QByteArray &fragmentShaderCode)
void | geometryShaderCodeChanged(const QByteArray &geometryShaderCode)
void | logChanged(const QString &log)
void | statusChanged(Qt3DRender::QShaderProgram::Status status)
void | tessellationControlShaderCodeChanged(const QByteArray &tessellationControlShaderCode)
void | tessellationEvaluationShaderCodeChanged(const QByteArray &tessellationEvaluationShaderCode)
void | vertexShaderCodeChanged(const QByteArray &vertexShaderCode)

## Static Public Members

QByteArray | loadSource(const QUrl &sourceUrl)

## Detailed Description

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:

     QParameter *parameter = new QParameter();
     parameter->setName("myColor");
     parameter->setValue(QVariant::fromValue(QColor(Qt::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));
     }

## Member Type Documentation

### `[since 5.15]` enum QShaderProgram::Format

This enum identifies the format of the shader code used.

Constant | Value | Description
--- | --- | ---
`Qt3DRender::QShaderProgram::GLSL` | `0` | OpenGL
`Qt3DRender::QShaderProgram::SPIRV` | `1` | Vulkan, OpenGL 5

This enum was introduced or modified in Qt 5.15.

### enum QShaderProgram::ShaderType

This enum identifies the type of shader used.

Constant | Value | Description
--- | --- | ---
`Qt3DRender::QShaderProgram::Vertex` | `0` | Vertex shader
`Qt3DRender::QShaderProgram::Fragment` | `1` | Fragment shader
`Qt3DRender::QShaderProgram::TessellationControl` | `2` | Tesselation control shader
`Qt3DRender::QShaderProgram::TessellationEvaluation` | `3` | Tesselation evaluation shader
`Qt3DRender::QShaderProgram::Geometry` | `4` | Geometry shader
`Qt3DRender::QShaderProgram::Compute` | `5` | Compute shader

### enum QShaderProgram::Status

This enum identifies the status of shader used.

Constant | Value | Description
--- | --- | ---
`Qt3DRender::QShaderProgram::NotReady` | `0` | The shader hasn't been compiled and linked yet
`Qt3DRender::QShaderProgram::Ready` | `1` | The shader was successfully compiled
`Qt3DRender::QShaderProgram::Error` | `2` | An error occurred while compiling the shader

## Property Documentation

### computeShaderCode : QByteArray

Holds the compute shader code used by this shader program.

Access functions:

QByteArray | computeShaderCode() const
void | setComputeShaderCode(const QByteArray &computeShaderCode)

Notifier signal:

void | computeShaderCodeChanged(const QByteArray &computeShaderCode)

### `[since 5.15]` format : Format

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

This property was introduced in Qt 5.15.

Access functions:

Qt3DRender::QShaderProgram::Format | format() const
void | setFormat(Qt3DRender::QShaderProgram::Format format)

Notifier signal:

void | formatChanged(Qt3DRender::QShaderProgram::Format format)

### fragmentShaderCode : QByteArray

Holds the fragment shader code used by this shader program.

Access functions:

QByteArray | fragmentShaderCode() const
void | setFragmentShaderCode(const QByteArray &fragmentShaderCode)

Notifier signal:

void | fragmentShaderCodeChanged(const QByteArray &fragmentShaderCode)

### geometryShaderCode : QByteArray

Holds the geometry shader code used by this shader program.

Access functions:

QByteArray | geometryShaderCode() const
void | setGeometryShaderCode(const QByteArray &geometryShaderCode)

Notifier signal:

void | geometryShaderCodeChanged(const QByteArray &geometryShaderCode)

### `[read-only]` log : const QString

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

Access functions:

QString | log() const

Notifier signal:

void | logChanged(const QString &log)

### `[read-only]` status : const Status

Holds the status of the current shader program.

Access functions:

Qt3DRender::QShaderProgram::Status | status() const

Notifier signal:

void | statusChanged(Qt3DRender::QShaderProgram::Status status)

### tessellationControlShaderCode : QByteArray

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

Access functions:

QByteArray | tessellationControlShaderCode() const
void | setTessellationControlShaderCode(const QByteArray &tessellationControlShaderCode)

Notifier signal:

void | tessellationControlShaderCodeChanged(const QByteArray &tessellationControlShaderCode)

### tessellationEvaluationShaderCode : QByteArray

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

Access functions:

QByteArray | tessellationEvaluationShaderCode() const
void | setTessellationEvaluationShaderCode(const QByteArray &tessellationEvaluationShaderCode)

Notifier signal:

void | tessellationEvaluationShaderCodeChanged(const QByteArray &tessellationEvaluationShaderCode)

### vertexShaderCode : QByteArray

Holds the vertex shader code used by this shader program.

Access functions:

QByteArray | vertexShaderCode() const
void | setVertexShaderCode(const QByteArray &vertexShaderCode)

Notifier signal:

void | vertexShaderCodeChanged(const QByteArray &vertexShaderCode)

## Member Function Documentation

### `[static invokable]` QByteArray QShaderProgram::loadSource(const QUrl &sourceUrl)

Returns the shader code loaded from sourceUrl.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

### void QShaderProgram::setShaderCode(Qt3DRender::QShaderProgram::ShaderType type, const QByteArray &shaderCode)

Sets the shader code for type of shader to the shaderCode.

See also shaderCode().

### QByteArray QShaderProgram::shaderCode(Qt3DRender::QShaderProgram::ShaderType type) const

Returns the shader code for type.

See also setShaderCode().

### Qt3DRender::QShaderProgram::Status QShaderProgram::status() const

Returns the status of the current shader program.

Note: Getter function for property status.