Qt 5.7 | Qt Data Visualization | Textured Surface Example | topographicseries.cpp Example File

Qt 5.7.1 Reference Documentation

# topographicseries.cpp Example File

texturesurface/topographicseries.cpp

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      #include "topographicseries.h"

      using namespace QtDataVisualization;

      // Value used to encode height data as RGB value on PNG file
      const float packingFactor = 11983.0f;

      TopographicSeries::TopographicSeries()
      {
          setDrawMode(QSurface3DSeries::DrawSurface);
          setFlatShadingEnabled(true);
          setBaseColor(Qt::white);
      }

      TopographicSeries::~TopographicSeries()
      {
      }

      void TopographicSeries::setTopographyFile(const QString file, float width, float height)
      {
          QImage heightMapImage(file);
          uchar *bits = heightMapImage.bits();
          int imageHeight = heightMapImage.height();
          int imageWidth = heightMapImage.width();
          int widthBits = imageWidth * 4;
          float stepX = width / float(imageWidth);
          float stepZ = height / float(imageHeight);

          QSurfaceDataArray *dataArray = new QSurfaceDataArray;
          dataArray->reserve(imageHeight);
          for (int i = 0; i < imageHeight; i++) {
              int p = i * widthBits;
              float z = height - float(i) * stepZ;
              QSurfaceDataRow *newRow = new QSurfaceDataRow(imageWidth);
              for (int j = 0; j < imageWidth; j++) {
                  uchar aa = bits[p + 0];
                  uchar rr = bits[p + 1];
                  uchar gg = bits[p + 2];
                  uint color = uint((gg << 16) + (rr << 8) + aa);
                  float y = float(color) / packingFactor;
                  (*newRow)[j].setPosition(QVector3D(float(j) * stepX, y, z));
                  p = p + 4;
              }
              *dataArray << newRow;
          }

          dataProxy()->resetArray(dataArray);

          m_sampleCountX = float(imageWidth);
          m_sampleCountZ = float(imageHeight);
      }