* any line completely parallel to the portal is rejected
* any line with one end on the same straight line than the portal is solely decided by the other vertex.
* any line with both ends behind the portal cannot be visible inside, so there's no need to check for an intersection with the view range.
* due to the above P_IntersectLines could be removed as it was redundant.
* for any line that does intersect with the portal straight, do a reverse check: If both ends of the portal lie on the other side of the line than the viewpoint, the line is between viewpoint and portal and needs to be rejected.
This fixes nearly all the phantom wall glitches in the demo map.
* when starting directly on a blockline the trace was offset by one map unit. Do this only for the internal block trace calculations but not for the variable that's being exposed to the outside because in rare situations that can create incorrect values.
* using startfrac could lead to an actor whose inside was right at that positon to be missed.
* when using startfrac the adjusted trace start was not used for all calculations, which could cause the trace to fail.
With these issues fixed, P_AimLineAttack can now successfully navigate line portals.
To allow processing the hit through an arbitrary portal without reference to the portal group table, P_AimLineAttack and P_LineAttack need to pass some more info than just the linetarget.
We need the relative positions of shooter and target within the visual reference of the other to calculate proper angles and we need to know if such a portal was crossed at all, because a few things, e.g. seeker missiles won't work with them.
- fixed setup of target acquisition for the Mage Staff.
The pre-acquired seeker target was never passed to the spawned projectiles.
- converted the P_TranslatePortal* functions to use floating point trigonometry. The combination of R_PointToAngle and finesine even created discrepancies with perfectly parallel portals which is just not acceptable.
- added a function to FPathTraverse to relocate the trace and restart from the new position.
- made P_UseLines portal aware. Traversal through line portals is complete (all types, even teleporters), whether sector portals need better treatment remains to be seen - at the moment it only checks the range at the player's vertical center.
The function to do the work scanned the full list of drawsegs to find portals, which with a large amount of masked geometry and/or drawsegs could become extremely slow.
Changed it so that R_DrawMasked collects all portal related drawsegs up front so that the actual clipping code can
a) scan a far shorter list and
b) can skip half of the validation.
Also using P_PointOnLinePrecise to shave off a small bit of additional time.
The reason is that in such a case it is very likely that the IWAD defines its own menu and will most likely not provide all assets for the base definitions. See 'Adventures of Square' for an example.
Attempts to output errors with bad characters encountered during text lumps parsing were failed miserably because of UTF-8 conversion
Example: loading of GZ-Models-r16.pk3 with GZDoom caused 'NSConcreteAttributedString initWithString:: nil value' exception
