diff options
| -rw-r--r-- | engines/scumm/he/logic_he.cpp | 44 |
1 files changed, 26 insertions, 18 deletions
diff --git a/engines/scumm/he/logic_he.cpp b/engines/scumm/he/logic_he.cpp index 4ccc2ac5e8..371ea6b979 100644 --- a/engines/scumm/he/logic_he.cpp +++ b/engines/scumm/he/logic_he.cpp @@ -322,24 +322,32 @@ int32 LogicHErace::op_1130(int32 *args) { } int32 LogicHErace::op_1140(int32 *args) { - double arg2 = -args[2] * args[2]; - double arg3 = -args[3] * args[3]; - double sq = sqrt(arg2 + arg3); - double res; - - arg2 = arg2 / sq; - arg3 = arg3 / sq; - - res = (args[0] - 2 * (arg2 * args[0] + arg3 * args[1]) * arg2) * 0.86956525; - - writeScummVar(108, (int32)res); - - res = args[1] - 2 * (arg2 * args[0] + arg3 * args[1]) * arg3; - - if (-args[3] * args[3] >= 0) - res *= 0.83333331f; - - writeScummVar(109, (int32)res); + // This functions seems to perform some kind of projection: We project + // the vector (arg2,arg3) onto the vector (arg0,arg1), but also apply + // some kind of distortion factor ?!? + double x = args[2], y = args[3]; + + // We start by normalizing the vector described by arg2 and arg3. + // So compute its length and divide the x and y coordinates + const double sq = sqrt(x*x + y*y); + x /= sq; + y /= sq; + + // Compute the scaler product of the vectors (arg0,arg1) and (x,y) + const double scalarProduct = x * args[0] + y * args[1]; + + // Finally compute the projection of (arg2,arg3) onto (arg0,arg1) + double projX = args[0] - 2 * scalarProduct * args[2]; + double projY = args[1] - 2 * scalarProduct * args[3]; + + projX *= 0.86956525; // FIXME: Why is this here? + + writeScummVar(108, (int32)projX); + + if (args[3] >= 0) // FIXME: Why is this here? + projY *= 0.83333331f; // FIXME: This value looks like 5/6 + + writeScummVar(109, (int32)projY); return 1; } |