simplematerial.cpp Example File

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 #include <qguiapplication.h>

 #include <qsgmaterial.h>
 #include <qsgnode.h>

 #include <qquickitem.h>
 #include <qquickview.h>

 #include <qsgsimplerectnode.h>

 #include <qsgsimplematerial.h>

 struct State
 {
     QColor color;

     int compare(const State *other) const {
         uint rgb = color.rgba();
         uint otherRgb = other->color.rgba();

         if (rgb == otherRgb) {
             return 0;
         } else if (rgb < otherRgb) {
             return -1;
         } else {
             return 1;
         }
     }
 };

 class Shader : public QSGSimpleMaterialShader<State>
 {
     QSG_DECLARE_SIMPLE_COMPARABLE_SHADER(Shader, State);
 public:

     const char *vertexShader() const override {
         return
                 "attribute highp vec4 aVertex;                              \n"
                 "attribute highp vec2 aTexCoord;                            \n"
                 "uniform highp mat4 qt_Matrix;                              \n"
                 "varying highp vec2 texCoord;                               \n"
                 "void main() {                                              \n"
                 "    gl_Position = qt_Matrix * aVertex;                     \n"
                 "    texCoord = aTexCoord;                                  \n"
                 "}";
     }

     const char *fragmentShader() const override {
         return
                 "uniform lowp float qt_Opacity;                             \n"
                 "uniform lowp vec4 color;                                   \n"
                 "varying highp vec2 texCoord;                               \n"
                 "void main ()                                               \n"
                 "{                                                          \n"
                 "    gl_FragColor = texCoord.y * texCoord.x * color * qt_Opacity;  \n"
                 "}";
     }
     QList<QByteArray> attributes() const override
     {
         return QList<QByteArray>() << "aVertex" << "aTexCoord";
     }
     void updateState(const State *state, const State *) override
     {
         program()->setUniformValue(id_color, state->color);
     }
     void resolveUniforms() override
     {
         id_color = program()->uniformLocation("color");
     }

 private:
     int id_color;
 };

 class ColorNode : public QSGGeometryNode
 {
 public:
     ColorNode()
         : m_geometry(QSGGeometry::defaultAttributes_TexturedPoint2D(), 4)
     {
         setGeometry(&m_geometry);

         QSGSimpleMaterial<State> *material = Shader::createMaterial();
         material->setFlag(QSGMaterial::Blending);
         setMaterial(material);
         setFlag(OwnsMaterial);
     }

     QSGGeometry m_geometry;
 };

 class Item : public QQuickItem
 {
     Q_OBJECT

     Q_PROPERTY(QColor color READ color WRITE setColor NOTIFY colorChanged)

 public:

     Item()
     {
         setFlag(ItemHasContents, true);
     }

     void setColor(const QColor &color) {
         if (m_color != color) {
             m_color = color;
             emit colorChanged();
             update();
         }
     }
     QColor color() const {
         return m_color;
     }

 signals:
     void colorChanged();

 private:
   QColor m_color;

 public:
     QSGNode *updatePaintNode(QSGNode *node, UpdatePaintNodeData *) override
     {
         ColorNode *n = static_cast<ColorNode *>(node);
         if (!node)
             n = new ColorNode();

         QSGGeometry::updateTexturedRectGeometry(n->geometry(), boundingRect(), QRectF(0, 0, 1, 1));
         static_cast<QSGSimpleMaterial<State>*>(n->material())->state()->color = m_color;

         n->markDirty(QSGNode::DirtyGeometry | QSGNode::DirtyMaterial);

         return n;
     }
 };
 int main(int argc, char **argv)
 {
     QGuiApplication app(argc, argv);

     qmlRegisterType<Item>("SimpleMaterial", 1, 0, "SimpleMaterialItem");

     QQuickView view;
     view.setResizeMode(QQuickView::SizeRootObjectToView);
     view.setSource(QUrl("qrc:///scenegraph/simplematerial/main.qml"));
     view.show();

     return app.exec();
 }

 #include "simplematerial.moc"