Duke07 v0.21b

v0.21 features (April 22, 2026):

• first attempt to implement wall aligned sprite portals.
  They're like 1-sided only but allow to connect any part of a map,
  in any place, via sprite portal, forming a window passage. It was
  developed really throughly to make sure they don't bog even systems
  as old as 486SX too much and not cause errors and crashes.

  HOW to create them: select a tile #4096 (PORTAL0), put it anywhere in map,
  make it flat (recommended) by placing a cursor at them and pressing "R",
  you may align them to walls by pressing "O", hold shift and hold left
  moust button and pull them slightly away from the wall so that it doesn't
  get swolen by it. Then place a tile #621 (CAMERA1) in any place of a map
  where you want this portal to show image from. Duplicate CAMERA1 and give
  it a tile #5062 (PRTLTELEPDEST) - that's your teleport destination. The
  engine makes both CAMERA1 and PRTLTELEPDEST that ARE LINKED to a portal
  INVISIBLE.

  Give your portal a hitag that corresponds to a lotag of CAMERA1 and
  PRTLTELEPDEST (yeah CAMERA1 and PRTLTELEPDEST are configured SAME WAY!).
  For example, PORTAL(hitag:9970,lotag:0), CAMERA1(hitag:0,lotag9970),
  PRTLTELEPDEST(hitag:0,lotag9970).
  E.g, they're set just like security cameras and don't interfere with them
  but make sure NOT to use a CAMERA1 sprite that is already connected to
  any security camera. Get in 2D mode (NumPad ENTER), get cursor
  over a sprite, press ALT+H to assign a hitag, enter a value, press reg-
  -ular ENTER, then press ALT+T to assign a lotag, enter a value, press reg
  -ular ENTER again.
  At this time you can only create 1 PORTAL PAIR (PORTAL0 and PORTAL1), do
  NOT use the same tile PORTAL0 for another side! Use PORTAL1 like that
  PORTAL1(hitag:9971,lotag:0), CAMERA1(hitag:0,lotag9971),
  PRTLTELEPDEST(hitag:0,lotag9971).

  Known limitations:

  • there's just ONE pair PORTAL0, PORTAL1, more to come;

  • low detail mode doesn't update picture in bottom left corner,
    I don't know how to fix this yet. At least I could fix tilt!

  • D07LQ2X still draws scanline tutti-frutti inside portals because
    the asm routines are designed to draw 320x200 image, not 128x128.
    The way to fix that would be externing "long ydim" in asm, load
    that in a register and use instead of hardcoded "200" or whatever
    value is there...

  • parallax inside portals suck, it's a subject to improve.

  • PORTAL tiles MUST BE SQUARE dimensions like 128x128 (low quality),
    192x192, 256x256 etc to work properly, there is NO way to fix that
    because there is NO need to do that as you may still resize sprite
    as you wish and it's not going to stretch contents inside.

  • it's best to have the same sizes of sprites for one pair like
    PORTAL0 and PORTAL1. In case it goes crazy, you'd delete and
    create them again without copy pasting one another for best
    stability.

     --- implementation details or how it works start ---
    

  global.c
  add new variables below "short camsprite":
  short portalsprite0 = -1; short portalsprite1 = -1;
  duke3d.h
  extern those two new variables below "extern char env_music_fn[4][13];"
  "extern short camsprite, portalsprite0, portalsprite1;"
  actors.c:
  for each PORTAL#x tile create a function that's gonna act like a trigger
  to activate this particular PORTAL#x tile. movestandablesportal0(ID#128)
  for PORTAL0 and movestandablesportal1(ID#129) for PORTAL1.
  game.c
  include "portals.c" file before displayrooms function, modify it as well
  in order to call particular portal drawing functions as se40codeportal#x
  and se40_DrawPortal#x and restore screen after them. Make a function
  before "short spawn" - startspriteportal and call movestandablesportal0,
  movestandablesportal1 inside. Modify function "domovethings" in order
  to call "startspriteportal" function after "movefta();" call.
  Modify function "short spawn" in order to include "PORTAL0 and PORTAL1"
  actors to be included in this line "if( PN != SPEAKER && PN != LETTER..."
  Place new cases on the new line like if(PN!=PORTAL0&&PN!=PORTAL1 etc),
  if not done, portals are not going to activate drawing automatically.
  In the same function "short spawn" extend T temp_data from 6 to 12...
  like "T1=T2=T3=T4=T5=T6=T7=T8=T9=T10=T11=T12=0;" In the same function,
  add "case PORTAL0, case PORTAL1" before or after "case VIEWSCREEN".
  Modify "case CAMERA1-CAMERA4-CAMERAPOLE" to identify cameras linked to
  portals and hide them. Also add "case PRTLTELEPDEST" to hide them too.
  portals.c contains code to draw portals to their respectve tiles.
  you can add it right in game.c before "displayrooms" but it was decided
  to put them out in a separate file for an ease of coding. Make sure that
  if you changed portals.c, you must delete "game.obj" before recompile,
  otherwise the changes are not going to become.
  sector.c. Modify function "void checksectors", the very beginning
  of that function contains a code of portals to teleport player in 3D
  space. That means it will not teleport you if you jump above it (made
  specially to allow for better 3D like windows and doors place on facade
  of multistory buildings). That makes it possible to stack many different
  portals in the same X,Y space but different height so you can have
  PORTAL0-1 pair on story #3 and PORTAL2-3 pair on story #4 for example
  (I didn't implement more than 1 pair though). Make sure that this version
  only teleports from a CENTER of a sprite, so that's a disatvantage I'm
  looking forward to fix...
  names.h, soundefs.h, user.con include new cases PORTAL0 4960,
  PORTAL1 4961, PRTLTELEPDEST 5062.
  engine.c, eng386.c. Modify "drawsprite and drawsprite_LQ2X" functs
  in order to depict texture contents on flats sprites like parascan does
  to floors and ceilings "parallax textures" but inside a trapezoid frame,
  also known as a "wall aligned flat sprite". I'd like to do the same to
  ground aligned sprites so that we could have holes in floors, ceilings.
  --- implementation details or how it works finish ---