QShaderProgram

Encapsulates a Shader Program. More…

Synopsis

Functions

• def computeShaderCode ()

• def format ()

• def fragmentShaderCode ()

• def geometryShaderCode ()

• def log ()

• def setFormat (format)

• def setShaderCode (type, shaderCode)

• def shaderCode (type)

• def status ()

• def tessellationControlShaderCode ()

• def tessellationEvaluationShaderCode ()

• def vertexShaderCode ()

Slots

• def setComputeShaderCode (computeShaderCode)

• def setFragmentShaderCode (fragmentShaderCode)

• def setGeometryShaderCode (geometryShaderCode)

• def setTessellationControlShaderCode (tessellationControlShaderCode)

• def setTessellationEvaluationShaderCode (tessellationEvaluationShaderCode)

• def setVertexShaderCode (vertexShaderCode)

Signals

• def computeShaderCodeChanged (computeShaderCode)

• def formatChanged (format)

• def fragmentShaderCodeChanged (fragmentShaderCode)

• def geometryShaderCodeChanged (geometryShaderCode)

• def logChanged (log)

• def statusChanged (status)

• def tessellationControlShaderCodeChanged (tessellationControlShaderCode)

• def tessellationEvaluationShaderCodeChanged (tessellationEvaluationShaderCode)

• def vertexShaderCodeChanged (vertexShaderCode)

Static functions

• def loadSource (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));
}

class PySide6.Qt3DRender.Qt3DRender.QShaderProgram([parent=None])

Parameters

parent – PySide6.Qt3DCore.Qt3DCore.QNode

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.ShaderType

This enum identifies the type of shader used.

Constant	Description
Qt3DRender.QShaderProgram.Vertex	Vertex shader
Qt3DRender.QShaderProgram.Fragment	Fragment shader
Qt3DRender.QShaderProgram.TessellationControl	Tesselation control shader
Qt3DRender.QShaderProgram.TessellationEvaluation	Tesselation evaluation shader
Qt3DRender.QShaderProgram.Geometry	Geometry shader
Qt3DRender.QShaderProgram.Compute	Compute shader

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.Status

This enum identifies the status of shader used.

Constant	Description
Qt3DRender.QShaderProgram.NotReady	The shader hasn’t been compiled and linked yet
Qt3DRender.QShaderProgram.Ready	The shader was successfully compiled
Qt3DRender.QShaderProgram.Error	An error occurred while compiling the shader

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.Format

This enum identifies the format of the shader code used.

Constant	Description
Qt3DRender.QShaderProgram.GLSL	OpenGL
Qt3DRender.QShaderProgram.SPIRV	Vulkan, OpenGL 5

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.computeShaderCode()

Return type

PySide6.QtCore.QByteArray

Holds the compute shader code used by this shader program.

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.computeShaderCodeChanged(computeShaderCode)

Parameters

computeShaderCode – PySide6.QtCore.QByteArray

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.format()

Return type

Format

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

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.formatChanged(format)

Parameters

format – Format

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.fragmentShaderCode()

Return type

PySide6.QtCore.QByteArray

Holds the fragment shader code used by this shader program.

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.fragmentShaderCodeChanged(fragmentShaderCode)

Parameters

fragmentShaderCode – PySide6.QtCore.QByteArray

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.geometryShaderCode()

Return type

PySide6.QtCore.QByteArray

Holds the geometry shader code used by this shader program.

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.geometryShaderCodeChanged(geometryShaderCode)

Parameters

geometryShaderCode – PySide6.QtCore.QByteArray

static PySide6.Qt3DRender.Qt3DRender.QShaderProgram.loadSource(sourceUrl)

Parameters

sourceUrl – PySide6.QtCore.QUrl

Return type

PySide6.QtCore.QByteArray

Returns the shader code loaded from sourceUrl.

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.log()

Return type

str

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

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.logChanged(log)

Parameters

log – str

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.setComputeShaderCode(computeShaderCode)

Parameters

computeShaderCode – PySide6.QtCore.QByteArray

Holds the compute shader code used by this shader program.

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.setFormat(format)

Parameters

format – Format

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

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.setFragmentShaderCode(fragmentShaderCode)

Parameters

fragmentShaderCode – PySide6.QtCore.QByteArray

Holds the fragment shader code used by this shader program.

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.setGeometryShaderCode(geometryShaderCode)

Parameters

geometryShaderCode – PySide6.QtCore.QByteArray

Holds the geometry shader code used by this shader program.

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.setShaderCode(type, shaderCode)

Parameters

• type – ShaderType

• shaderCode – PySide6.QtCore.QByteArray

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

See also

shaderCode()

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.setTessellationControlShaderCode(tessellationControlShaderCode)

Parameters

tessellationControlShaderCode – PySide6.QtCore.QByteArray

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

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.setTessellationEvaluationShaderCode(tessellationEvaluationShaderCode)

Parameters

tessellationEvaluationShaderCode – PySide6.QtCore.QByteArray

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

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.setVertexShaderCode(vertexShaderCode)

Parameters

vertexShaderCode – PySide6.QtCore.QByteArray

Holds the vertex shader code used by this shader program.

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.shaderCode(type)

Parameters

type – ShaderType

Return type

PySide6.QtCore.QByteArray

Returns the shader code for type.

See also

setShaderCode()

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.status()

Return type

Status

Holds the status of the current shader program.

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.statusChanged(status)

Parameters

status – Status

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.tessellationControlShaderCode()

Return type

PySide6.QtCore.QByteArray

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

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.tessellationControlShaderCodeChanged(tessellationControlShaderCode)

Parameters

tessellationControlShaderCode – PySide6.QtCore.QByteArray

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.tessellationEvaluationShaderCode()

Return type

PySide6.QtCore.QByteArray

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

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.tessellationEvaluationShaderCodeChanged(tessellationEvaluationShaderCode)

Parameters

tessellationEvaluationShaderCode – PySide6.QtCore.QByteArray

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.vertexShaderCode()

Return type

PySide6.QtCore.QByteArray

Holds the vertex shader code used by this shader program.

PySide6.Qt3DRender.Qt3DRender.QShaderProgram.vertexShaderCodeChanged(vertexShaderCode)

Parameters

vertexShaderCode – PySide6.QtCore.QByteArray