QShaderProgram Class
class Qt3DRender::QShaderProgramEncapsulates a Shader Program. More...
Header: | #include <QShaderProgram> |
CMake: | find_package(Qt6 REQUIRED COMPONENTS 3drender) target_link_libraries(mytarget PRIVATE Qt6::3drender) |
qmake: | QT += 3drender |
Instantiated By: | ShaderProgram |
Inherits: | Qt3DCore::QNode |
Public Types
enum | Format { GLSL, SPIRV } |
enum | ShaderType { Vertex, Fragment, TessellationControl, TessellationEvaluation, Geometry, Compute } |
enum | Status { NotReady, Ready, Error } |
Properties
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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
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 |
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) |
format : Format
Holds the format of the code provided on the ShaderProgram. The default is ShaderProgram.GLSL
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.