simplematerial.cpp Example File | Qt Quick 5.12.8

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- simplematerial.cpp Example File
- Qt 5.12.8 Reference Documentation

# simplematerial.cpp Example File

scenegraph/simplematerial/simplematerial.cpp

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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"