Qt 5.11 | Qt Widgets | Boxes | roundedbox.cpp Example File

Qt 5.11.3 Reference Documentation

# roundedbox.cpp Example File

graphicsview/boxes/roundedbox.cpp

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      #include "roundedbox.h"

      //============================================================================//
      //                                P3T2N3Vertex                                //
      //============================================================================//

      VertexDescription P3T2N3Vertex::description[] = {
          {VertexDescription::Position, GL_FLOAT, SIZE_OF_MEMBER(P3T2N3Vertex, position) / sizeof(float), 0, 0},
          {VertexDescription::TexCoord, GL_FLOAT, SIZE_OF_MEMBER(P3T2N3Vertex, texCoord) / sizeof(float), sizeof(QVector3D), 0},
          {VertexDescription::Normal, GL_FLOAT, SIZE_OF_MEMBER(P3T2N3Vertex, normal) / sizeof(float), sizeof(QVector3D) + sizeof(QVector2D), 0},

          {VertexDescription::Null, 0, 0, 0, 0},
      };

      //============================================================================//
      //                                GLRoundedBox                                //
      //============================================================================//

      float lerp(float a, float b, float t)
      {
          return a * (1.0f - t) + b * t;
      }

      GLRoundedBox::GLRoundedBox(float r, float scale, int n)
          : GLTriangleMesh<P3T2N3Vertex, unsigned short>((n+2)*(n+3)*4, (n+1)*(n+1)*24+36+72*(n+1))
      {
          int vidx = 0, iidx = 0;
          int vertexCountPerCorner = (n + 2) * (n + 3) / 2;

          P3T2N3Vertex *vp = m_vb.lock();
          unsigned short *ip = m_ib.lock();

          if (!vp || !ip) {
              qWarning("GLRoundedBox::GLRoundedBox: Failed to lock vertex buffer and/or index buffer.");
              m_ib.unlock();
              m_vb.unlock();
              return;
          }

          for (int corner = 0; corner < 8; ++corner) {
              QVector3D centre(corner & 1 ? 1.0f : -1.0f,
                      corner & 2 ? 1.0f : -1.0f,
                      corner & 4 ? 1.0f : -1.0f);
              int winding = (corner & 1) ^ ((corner >> 1) & 1) ^ (corner >> 2);
              int offsX = ((corner ^ 1) - corner) * vertexCountPerCorner;
              int offsY = ((corner ^ 2) - corner) * vertexCountPerCorner;
              int offsZ = ((corner ^ 4) - corner) * vertexCountPerCorner;

              // Face polygons
              if (winding) {
                  ip[iidx++] = vidx;
                  ip[iidx++] = vidx + offsX;
                  ip[iidx++] = vidx + offsY;

                  ip[iidx++] = vidx + vertexCountPerCorner - n - 2;
                  ip[iidx++] = vidx + vertexCountPerCorner - n - 2 + offsY;
                  ip[iidx++] = vidx + vertexCountPerCorner - n - 2 + offsZ;

                  ip[iidx++] = vidx + vertexCountPerCorner - 1;
                  ip[iidx++] = vidx + vertexCountPerCorner - 1 + offsZ;
                  ip[iidx++] = vidx + vertexCountPerCorner - 1 + offsX;
              }

              for (int i = 0; i < n + 2; ++i) {

                  // Edge polygons
                  if (winding && i < n + 1) {
                      ip[iidx++] = vidx + i + 1;
                      ip[iidx++] = vidx;
                      ip[iidx++] = vidx + offsY + i + 1;
                      ip[iidx++] = vidx + offsY;
                      ip[iidx++] = vidx + offsY + i + 1;
                      ip[iidx++] = vidx;

                      ip[iidx++] = vidx + i;
                      ip[iidx++] = vidx + 2 * i + 2;
                      ip[iidx++] = vidx + i + offsX;
                      ip[iidx++] = vidx + 2 * i + offsX + 2;
                      ip[iidx++] = vidx + i + offsX;
                      ip[iidx++] = vidx + 2 * i + 2;

                      ip[iidx++] = (corner + 1) * vertexCountPerCorner - 1 - i;
                      ip[iidx++] = (corner + 1) * vertexCountPerCorner - 2 - i;
                      ip[iidx++] = (corner + 1) * vertexCountPerCorner - 1 - i + offsZ;
                      ip[iidx++] = (corner + 1) * vertexCountPerCorner - 2 - i + offsZ;
                      ip[iidx++] = (corner + 1) * vertexCountPerCorner - 1 - i + offsZ;
                      ip[iidx++] = (corner + 1) * vertexCountPerCorner - 2 - i;
                  }

                  for (int j = 0; j <= i; ++j) {
                      QVector3D normal = QVector3D(i - j, j, n + 1 - i).normalized();
                      QVector3D offset(0.5f - r, 0.5f - r, 0.5f - r);
                      QVector3D pos = centre * (offset + r * normal);

                      vp[vidx].position = scale * pos;
                      vp[vidx].normal = centre * normal;
                      vp[vidx].texCoord = QVector2D(pos.x() + 0.5f, pos.y() + 0.5f);

                      // Corner polygons
                      if (i < n + 1) {
                          ip[iidx++] = vidx;
                          ip[iidx++] = vidx + i + 2 - winding;
                          ip[iidx++] = vidx + i + 1 + winding;
                      }
                      if (i < n) {
                          ip[iidx++] = vidx + i + 1 + winding;
                          ip[iidx++] = vidx + i + 2 - winding;
                          ip[iidx++] = vidx + 2 * i + 4;
                      }

                      ++vidx;
                  }
              }

          }

          m_ib.unlock();
          m_vb.unlock();
      }