QParameter¶

Provides storage for a name and value pair. This maps to a shader uniform. More…

Synopsis¶

Functions¶

def name ()
def value ()

Slots¶

def setName (name)
def setValue (dv)

Signals¶

def nameChanged (name)
def valueChanged (value)

Detailed Description¶

A QParameter can be referenced by a QRenderPass , QTechnique , QEffect , QMaterial , QTechniqueFilter , QRenderPassFilter . At runtime, depending on which shader is selected for a given step of the rendering, the value contained in a QParameter will be converted and uploaded if the shader contains a uniform with a name matching that of the QParameter .

QParameter *param = new QParameter();
param->setName(QStringLiteral("diffuseColor"));
param->setValue(QColor::fromRgbF(0.0f, 0.0f, 1.0f, 1.0f));

// Alternatively you can create and set a QParameter this way
QParameter *param2 = new QParameter(QStringLiteral("diffuseColor"), QColor::fromRgbF(0.0f, 0.0f, 1.0f, 1.0f));

// Such QParameters will work with the following GLSL uniform shader declarations
// uniform vec4 diffuseColor;
// uniform vec3 diffuseColor;
// uniform vec2 diffuseColor;
// uniform float diffuseColor;

Note

some care must be taken to ensure the value wrapped by a QParameter can actually be converted to what the real uniform expect. Giving a value stored as an int where the actual shader uniform is of type float could result in undefined behaviors.

Note

when the targeted uniform is an array, the name should be the name of the uniform with [0] appended to it.

Note

QParameter node can not be disabled.

QParameter *param = new QParameter();
QVariantList values = QVariantList() << 0.0f << 1.0f << 2.0f << 3.0f << 4.0f << 883.0f << 1340.0f << 1584.0f;

param->setName(QStringLiteral("diffuseValues[0]"));
param->setValue(values);

// Matching GLSL shader uniform  declaration
// uniform float diffuseValues[8];

When it comes to texture support, the QParameter value should be set to the appropriate QAbstractTexture subclass that matches the sampler type of the shader uniform.

QTexture2D *texture = new QTexture2D();
...
QParameter *param = new QParameter();
param->setName(QStringLiteral("diffuseTexture"));
param->setValue(QVariant::fromValue(texture));

// Works with the following GLSL uniform shader declaration
// uniform sampler2D diffuseTexture

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QParameter¶

Synopsis¶

Functions¶

Slots¶

Signals¶

Detailed Description¶