Qt 5.11 | Qt OpenGL | Hello GL2 Example | logo.cpp Example File

Qt 5.11.3 Reference Documentation

# logo.cpp Example File

hellogl2/logo.cpp

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      #include "logo.h"
      #include <qmath.h>

      Logo::Logo()
          : m_count(0)
      {
          m_data.resize(2500 * 6);

          const GLfloat x1 = +0.06f;
          const GLfloat y1 = -0.14f;
          const GLfloat x2 = +0.14f;
          const GLfloat y2 = -0.06f;
          const GLfloat x3 = +0.08f;
          const GLfloat y3 = +0.00f;
          const GLfloat x4 = +0.30f;
          const GLfloat y4 = +0.22f;

          quad(x1, y1, x2, y2, y2, x2, y1, x1);
          quad(x3, y3, x4, y4, y4, x4, y3, x3);

          extrude(x1, y1, x2, y2);
          extrude(x2, y2, y2, x2);
          extrude(y2, x2, y1, x1);
          extrude(y1, x1, x1, y1);
          extrude(x3, y3, x4, y4);
          extrude(x4, y4, y4, x4);
          extrude(y4, x4, y3, x3);

          const int NumSectors = 100;

          for (int i = 0; i < NumSectors; ++i) {
              GLfloat angle = (i * 2 * M_PI) / NumSectors;
              GLfloat angleSin = qSin(angle);
              GLfloat angleCos = qCos(angle);
              const GLfloat x5 = 0.30f * angleSin;
              const GLfloat y5 = 0.30f * angleCos;
              const GLfloat x6 = 0.20f * angleSin;
              const GLfloat y6 = 0.20f * angleCos;

              angle = ((i + 1) * 2 * M_PI) / NumSectors;
              angleSin = qSin(angle);
              angleCos = qCos(angle);
              const GLfloat x7 = 0.20f * angleSin;
              const GLfloat y7 = 0.20f * angleCos;
              const GLfloat x8 = 0.30f * angleSin;
              const GLfloat y8 = 0.30f * angleCos;

              quad(x5, y5, x6, y6, x7, y7, x8, y8);

              extrude(x6, y6, x7, y7);
              extrude(x8, y8, x5, y5);
          }
      }

      void Logo::add(const QVector3D &v, const QVector3D &n)
      {
          GLfloat *p = m_data.data() + m_count;
          *p++ = v.x();
          *p++ = v.y();
          *p++ = v.z();
          *p++ = n.x();
          *p++ = n.y();
          *p++ = n.z();
          m_count += 6;
      }

      void Logo::quad(GLfloat x1, GLfloat y1, GLfloat x2, GLfloat y2, GLfloat x3, GLfloat y3, GLfloat x4, GLfloat y4)
      {
          QVector3D n = QVector3D::normal(QVector3D(x4 - x1, y4 - y1, 0.0f), QVector3D(x2 - x1, y2 - y1, 0.0f));

          add(QVector3D(x1, y1, -0.05f), n);
          add(QVector3D(x4, y4, -0.05f), n);
          add(QVector3D(x2, y2, -0.05f), n);

          add(QVector3D(x3, y3, -0.05f), n);
          add(QVector3D(x2, y2, -0.05f), n);
          add(QVector3D(x4, y4, -0.05f), n);

          n = QVector3D::normal(QVector3D(x1 - x4, y1 - y4, 0.0f), QVector3D(x2 - x4, y2 - y4, 0.0f));

          add(QVector3D(x4, y4, 0.05f), n);
          add(QVector3D(x1, y1, 0.05f), n);
          add(QVector3D(x2, y2, 0.05f), n);

          add(QVector3D(x2, y2, 0.05f), n);
          add(QVector3D(x3, y3, 0.05f), n);
          add(QVector3D(x4, y4, 0.05f), n);
      }

      void Logo::extrude(GLfloat x1, GLfloat y1, GLfloat x2, GLfloat y2)
      {
          QVector3D n = QVector3D::normal(QVector3D(0.0f, 0.0f, -0.1f), QVector3D(x2 - x1, y2 - y1, 0.0f));

          add(QVector3D(x1, y1, +0.05f), n);
          add(QVector3D(x1, y1, -0.05f), n);
          add(QVector3D(x2, y2, +0.05f), n);

          add(QVector3D(x2, y2, -0.05f), n);
          add(QVector3D(x2, y2, +0.05f), n);
          add(QVector3D(x1, y1, -0.05f), n);
      }