simplematerial.cpp Example File

  /****************************************************************************
  **
  ** Copyright (C) 2016 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the demonstration applications of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:BSD$
  ** Commercial License Usage
  ** Licensees holding valid commercial Qt licenses may use this file in
  ** accordance with the commercial license agreement provided with the
  ** Software or, alternatively, in accordance with the terms contained in
  ** a written agreement between you and The Qt Company. For licensing terms
  ** and conditions see https://www.qt.io/terms-conditions. For further
  ** information use the contact form at https://www.qt.io/contact-us.
  **
  ** BSD License Usage
  ** Alternatively, you may use this file under the terms of the BSD license
  ** as follows:
  **
  ** "Redistribution and use in source and binary forms, with or without
  ** modification, are permitted provided that the following conditions are
  ** met:
  **   * Redistributions of source code must retain the above copyright
  **     notice, this list of conditions and the following disclaimer.
  **   * Redistributions in binary form must reproduce the above copyright
  **     notice, this list of conditions and the following disclaimer in
  **     the documentation and/or other materials provided with the
  **     distribution.
  **   * Neither the name of The Qt Company Ltd nor the names of its
  **     contributors may be used to endorse or promote products derived
  **     from this software without specific prior written permission.
  **
  **
  ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
  **
  ** $QT_END_LICENSE$
  **
  ****************************************************************************/

  #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"