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();
  }