PySide6.Qt3DRender.Qt3DRender.QShaderProgram

class QShaderProgram

Encapsulates a Shader Program. More…

Inheritance diagram of PySide6.Qt3DRender.Qt3DRender.QShaderProgram

Synopsis

Properties

Methods

Slots

Signals

Static functions

Note

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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 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
class 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
class Format

This enum identifies the format of the shader code used.

Constant

Description

Qt3DRender.QShaderProgram.GLSL

OpenGL

Qt3DRender.QShaderProgram.SPIRV

Vulkan, OpenGL 5

Note

Properties can be used directly when from __feature__ import true_property is used or via accessor functions otherwise.

property computeShaderCodeᅟ: QByteArray

Holds the compute shader code used by this shader program.

Access functions:
property formatᅟ: Qt3DRender.QShaderProgram.Format

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

Access functions:
property fragmentShaderCodeᅟ: QByteArray

Holds the fragment shader code used by this shader program.

Access functions:
property geometryShaderCodeᅟ: QByteArray

Holds the geometry shader code used by this shader program.

Access functions:
property logᅟ: str

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

Access functions:
property statusᅟ: Qt3DRender.QShaderProgram.Status

Holds the status of the current shader program.

Access functions:
property tessellationControlShaderCodeᅟ: QByteArray

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

Access functions:
property tessellationEvaluationShaderCodeᅟ: QByteArray

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

Access functions:
property vertexShaderCodeᅟ: QByteArray

Holds the vertex shader code used by this shader program.

Access functions:
__init__([parent=None])
Parameters:

parent – QNode

computeShaderCode()
Return type:

QByteArray

See also

setComputeShaderCode()

Getter of property computeShaderCodeᅟ .

computeShaderCodeChanged(computeShaderCode)
Parameters:

computeShaderCode – QByteArray

Notification signal of property computeShaderCodeᅟ .

format()
Return type:

Format

See also

setFormat()

Getter of property formatᅟ .

formatChanged(format)
Parameters:

format – Format

Notification signal of property formatᅟ .

fragmentShaderCode()
Return type:

QByteArray

See also

setFragmentShaderCode()

Getter of property fragmentShaderCodeᅟ .

fragmentShaderCodeChanged(fragmentShaderCode)
Parameters:

fragmentShaderCode – QByteArray

Notification signal of property fragmentShaderCodeᅟ .

geometryShaderCode()
Return type:

QByteArray

See also

setGeometryShaderCode()

Getter of property geometryShaderCodeᅟ .

geometryShaderCodeChanged(geometryShaderCode)
Parameters:

geometryShaderCode – QByteArray

Notification signal of property geometryShaderCodeᅟ .

static loadSource(sourceUrl)
Parameters:

sourceUrl – QUrl

Return type:

QByteArray

Returns the shader code loaded from sourceUrl.

log()
Return type:

str

Getter of property logᅟ .

logChanged(log)
Parameters:

log – str

Notification signal of property logᅟ .

setComputeShaderCode(computeShaderCode)
Parameters:

computeShaderCode – QByteArray

See also

computeShaderCode()

Setter of property computeShaderCodeᅟ .

setFormat(format)
Parameters:

format – Format

See also

format()

Setter of property formatᅟ .

setFragmentShaderCode(fragmentShaderCode)
Parameters:

fragmentShaderCode – QByteArray

See also

fragmentShaderCode()

Setter of property fragmentShaderCodeᅟ .

setGeometryShaderCode(geometryShaderCode)
Parameters:

geometryShaderCode – QByteArray

See also

geometryShaderCode()

Setter of property geometryShaderCodeᅟ .

setShaderCode(type, shaderCode)
Parameters:

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

See also

shaderCode()

setTessellationControlShaderCode(tessellationControlShaderCode)
Parameters:

tessellationControlShaderCode – QByteArray

See also

tessellationControlShaderCode()

Setter of property tessellationControlShaderCodeᅟ .

setTessellationEvaluationShaderCode(tessellationEvaluationShaderCode)
Parameters:

tessellationEvaluationShaderCode – QByteArray

See also

tessellationEvaluationShaderCode()

Setter of property tessellationEvaluationShaderCodeᅟ .

setVertexShaderCode(vertexShaderCode)
Parameters:

vertexShaderCode – QByteArray

See also

vertexShaderCode()

Setter of property vertexShaderCodeᅟ .

shaderCode(type)
Parameters:

type – ShaderType

Return type:

QByteArray

Returns the shader code for type.

See also

setShaderCode()

status()
Return type:

Status

Returns the status of the current shader program.

Getter of property statusᅟ .

statusChanged(status)
Parameters:

status – Status

Notification signal of property statusᅟ .

tessellationControlShaderCode()
Return type:

QByteArray

See also

setTessellationControlShaderCode()

Getter of property tessellationControlShaderCodeᅟ .

tessellationControlShaderCodeChanged(tessellationControlShaderCode)
Parameters:

tessellationControlShaderCode – QByteArray

Notification signal of property tessellationControlShaderCodeᅟ .

tessellationEvaluationShaderCode()
Return type:

QByteArray

See also

setTessellationEvaluationShaderCode()

Getter of property tessellationEvaluationShaderCodeᅟ .

tessellationEvaluationShaderCodeChanged(tessellationEvaluationShaderCode)
Parameters:

tessellationEvaluationShaderCode – QByteArray

Notification signal of property tessellationEvaluationShaderCodeᅟ .

vertexShaderCode()
Return type:

QByteArray

See also

setVertexShaderCode()

Getter of property vertexShaderCodeᅟ .

vertexShaderCodeChanged(vertexShaderCode)
Parameters:

vertexShaderCode – QByteArray

Notification signal of property vertexShaderCodeᅟ .