Qt 5.6 | Qt Quick | Scene Graph - Graph | noisynode.cpp Example File

Qt 5.6.2 Reference Documentation

# noisynode.cpp Example File

scenegraph/graph/noisynode.cpp

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      #include "noisynode.h"

      #include <QtQuick/QSGSimpleMaterialShader>
      #include <QtQuick/QSGTexture>
      #include <QtQuick/QQuickWindow>

      #define NOISE_SIZE 64

      struct NoisyMaterial
      {
          ~NoisyMaterial() {
              delete texture;
          }

          QColor color;
          QSGTexture *texture;
      };

      class NoisyShader : public QSGSimpleMaterialShader<NoisyMaterial>
      {
          QSG_DECLARE_SIMPLE_SHADER(NoisyShader, NoisyMaterial)

      public:
          NoisyShader() : id_color(-1), id_texture(-1), id_textureSize(-1) {
              setShaderSourceFile(QOpenGLShader::Vertex, ":/scenegraph/graph/shaders/noisy.vsh");
              setShaderSourceFile(QOpenGLShader::Fragment, ":/scenegraph/graph/shaders/noisy.fsh");
          }

          QList<QByteArray> attributes() const {  return QList<QByteArray>() << "aVertex" << "aTexCoord"; }

          void updateState(const NoisyMaterial *m, const NoisyMaterial *) {

              // Set the color
              program()->setUniformValue(id_color, m->color);

              // Bind the texture and set program to use texture unit 0 (the default)
              m->texture->bind();

              // Then set the texture size so we can adjust the texture coordinates accordingly in the
              // vertex shader..
              QSize s = m->texture->textureSize();
              program()->setUniformValue(id_textureSize, QSizeF(1.0 / s.width(), 1.0 / s.height()));
          }

          void resolveUniforms() {
              id_texture = program()->uniformLocation("texture");
              id_textureSize = program()->uniformLocation("textureSize");
              id_color = program()->uniformLocation("color");

              // We will only use texture unit 0, so set it only once.
              program()->setUniformValue(id_texture, 0);
          }

      private:
          int id_color;
          int id_texture;
          int id_textureSize;
      };

      NoisyNode::NoisyNode(QQuickWindow *window)
      {
          // Make some noise...
          QImage image(NOISE_SIZE, NOISE_SIZE, QImage::Format_RGB32);
          uint *data = (uint *) image.bits();
          for (int i=0; i<NOISE_SIZE * NOISE_SIZE; ++i) {
              uint g = rand() & 0xff;
              data[i] = 0xff000000 | (g << 16) | (g << 8) | g;
          }

          QSGTexture *t = window->createTextureFromImage(image);
          t->setFiltering(QSGTexture::Nearest);
          t->setHorizontalWrapMode(QSGTexture::Repeat);
          t->setVerticalWrapMode(QSGTexture::Repeat);

          QSGSimpleMaterial<NoisyMaterial> *m = NoisyShader::createMaterial();
          m->state()->texture = t;
          m->state()->color = QColor::fromRgbF(0.95, 0.95, 0.97);
          m->setFlag(QSGMaterial::Blending);

          setMaterial(m);
          setFlag(OwnsMaterial, true);

          QSGGeometry *g = new QSGGeometry(QSGGeometry::defaultAttributes_TexturedPoint2D(), 4);
          QSGGeometry::updateTexturedRectGeometry(g, QRect(), QRect());
          setGeometry(g);
          setFlag(OwnsGeometry, true);
      }

      void NoisyNode::setRect(const QRectF &bounds)
      {
          QSGGeometry::updateTexturedRectGeometry(geometry(), bounds, QRectF(0, 0, 1, 1));
          markDirty(QSGNode::DirtyGeometry);
      }