noisynode.cpp Example File

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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);
  }