QSGMaterial Class

Detailed Description

The QSGMaterial class encapsulates rendering state for a shader program.

The QSGMaterial API is very low-level. A more convenient API, which provides almost all the same features, is available through QSGSimpleMaterialShader.

The QSGMaterial and QSGMaterialShader subclasses form a tight relationship. For one scene graph (including nested graphs), there is one unique QSGMaterialShader instance which encapsulates the QOpenGLShaderProgram the scene graph uses to render that material, such as a shader to flat coloring of geometry. Each QSGGeometryNode can have a unique QSGMaterial containing the how the shader should be configured when drawing that node, such as the actual color to used to render the geometry.

The QSGMaterial has two virtual functions that both need to be implemented. The function type() should return a unique instance for all instances of a specific subclass. The createShader() function should return a new instance of QSGMaterialShader, specific to the subclass of QSGMaterial.

A minimal QSGMaterial implementation could look like this:

class Material : public QSGMaterial
{
public:
    QSGMaterialType *type() const { static QSGMaterialType type; return &type; }
    QSGMaterialShader *createShader() const { return new Shader; }
};

Note: All classes with QSG prefix should be used solely on the scene graph's rendering thread. See Scene Graph and Rendering for more information.