simplematerial.cpp Example File

scenegraph/simplematerial/simplematerial.cpp

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  ** This file is part of the demonstration applications of the Qt Toolkit.
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  ** $QT_BEGIN_LICENSE:LGPL21$
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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 {
          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 {
          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
      {
          return QList<QByteArray>() << "aVertex" << "aTexCoord";
      }
      void updateState(const State *state, const State *)
      {
          program()->setUniformValue(id_color, state->color);
      }
      void resolveUniforms()
      {
          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 *)
      {
          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"