Function BmpCopyBlock2

xdevice.cpp:379–435

// of integers. Can be used to render only subsections of source pixels.

void BmpCopyBlock2(CONST Bitmap *bs, real x1, real y1, real x2, real y2,
  Bitmap *bd, int x3, int y3, int x4, int y4)
{
  int xd = x4-x3+1, yd = y4-y3+1, x, y, xT, yT, nR, nG, nB;
  real xs, ys, lonS, latS, rx, ry;
  byte *pbDst;
  flag fDoEclipse = fFalse;
  KV kv;

  // Sanity checks of coordinate bounds, which shouldn't ever fail.
  Assert(FBetween(x1, 0.0, (real)bs->x - rSmall));
  Assert(FBetween(y1, 0.0, (real)bs->y - rSmall));
  Assert(FBetween(x2, 0.0, (real)bs->x - rSmall));
  Assert(FBetween(y2, 0.0, (real)bs->y - rSmall));
  Assert(FBetween(x3, 0, bd->x-1));
  Assert(FBetween(y3, 0, bd->y-1));
  Assert(FBetween(x4, 0, bd->x-1));
  Assert(FBetween(y4, 0, bd->y-1));

  if (gs.fMollweide) {
    lonS = Tropical(planet[oSun]);
    latS = planetalt[oSun];
    EclToEqu(&lonS, &latS);
    lonS = Mod(lonS - cp0.lonMC + rDegHalf - Lon);
    if (us.fEclipse &&
      NCheckEclipseSolar(oEar, oMoo, oSun, NULL) > etNone)
      fDoEclipse = fTrue;
  }

  xs = (x2-x1) / (real)xd;
  ys = (y2-y1) / (real)yd;
  for (y = y3; y <= y4; y++) {
    pbDst = _PbXY(bd, x3, y);
    ry = y1 + (real)(y-y3) * ys;
    yT = (int)ry;
    if (!gs.fMollweide) {
      // Fast loop that just copies pixels.
      for (x = x3; x <= x4; x++) {
        xT = (int)(x1 + (real)(x-x3) * xs);
        _GetRGB(_PbXY(bs, xT, yT), &nR, &nG, &nB);
        _SetRGB(pbDst, nR, nG, nB);
        pbDst += cbPixelK;
      }
    } else {
      // Slower loop that may modify colors based on position on Earth.
      ry = ry * rDegMax / (real)bs->x;
      for (x = x3; x <= x4; x++) {
        rx = x1 + (real)(x-x3) * xs;
        xT = (int)rx;
        rx = rx * rDegMax / (real)bs->x;
        kv = _GetXY(bs, xT, yT);
        BmpDarkenKv(rx, ry, lonS, latS, fDoEclipse, &kv);
        BmpSetXY(bd, x, y, kv);
      }
    }
  }
}