QShaderProgram Class

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));
}

This enum identifies the format of the shader code used.

This enum was introduced or modified in Qt 5.15.

This enum identifies the type of shader used.

This enum identifies the status of shader used.

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)

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:

• format() const

• void setFormat( format)

Notifier signal:

• void formatChanged( format)

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)

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)

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)

Holds the status of the current shader program.

Access functions:

• status() const

Notifier signal:

• void statusChanged( status)

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)

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)

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)

Returns the shader code loaded from sourceUrl.

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

See Also▲

Returns the shader code for type.

See Also▲

Returns the status of the current shader program.