noisynode.cpp Example File | Qt Quick 5.12.9

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- noisynode.cpp Example File
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# noisynode.cpp Example File

scenegraph/graph/noisynode.cpp

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     #include "noisynode.h"

     #include <QtCore/QRandomGenerator>
     #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() {
             setShaderSourceFile(QOpenGLShader::Vertex, ":/scenegraph/graph/shaders/noisy.vsh");
             setShaderSourceFile(QOpenGLShader::Fragment, ":/scenegraph/graph/shaders/noisy.fsh");
         }

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

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

             // 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() override {
             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 = -1;
         int id_texture = -1;
         int id_textureSize = -1;
     };

     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 = QRandomGenerator::global()->bounded(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);
     }