Function DrawMapTriangle

xcharts0.cpp:1742–1775

// triangles should be nested a specified number of levels deep.

void DrawMapTriangle(real lon1, real lat1, real lon2, real lat2, real lon3,
  real lat3, flag fGlobe, int nScl, CIRC *pcr, real deg, int nLevel, int grf)
{
  real x1, y1, x2, y2, x3, y3;

  // Recursive case: Draw four smaller triangles composing this triangle.
  if (nLevel > 0) {
    SphRatio(lon1, lat1, lon2, lat2, 0.5, &x1, &y1);
    SphRatio(lon2, lat2, lon3, lat3, 0.5, &x2, &y2);
    SphRatio(lon3, lat3, lon1, lat1, 0.5, &x3, &y3);
    DrawMapTriangle(x1,   y1,   x2, y2, x3, y3, fGlobe, nScl, pcr, deg,
      nLevel-1, 7);
    DrawMapTriangle(lon1, lat1, x1, y1, x3, y3, fGlobe, nScl, pcr, deg,
      nLevel-1, grf & 5);
    DrawMapTriangle(lon2, lat2, x1, y1, x2, y2, fGlobe, nScl, pcr, deg,
      nLevel-1, grf & 5);
    DrawMapTriangle(lon3, lat3, x2, y2, x3, y3, fGlobe, nScl, pcr, deg,
      nLevel-1, grf & 5);
    return;
  }

  // Base case: Draw the three sides of the triangle.
  if (!fGlobe) {
    lon1 = Mod(lon1 + deg);
    lon2 = Mod(lon2 + deg);
    lon3 = Mod(lon3 + deg);
  }
  if (grf & 1)
    DrawMapLine(lon1, lat1, lon2, lat2, fGlobe, nScl, pcr, deg);
  if (grf & 2)
    DrawMapLine(lon2, lat2, lon3, lat3, fGlobe, nScl, pcr, deg);
  if (grf & 4)
    DrawMapLine(lon3, lat3, lon1, lat1, fGlobe, nScl, pcr, deg);
}


// Draw a square between four coordinates on the globe, in which other