src/tables.h

   1 // Emacs style mode select   -*- C++ -*-
   2 //-----------------------------------------------------------------------------
   3 //
   4 // Copyright(C) 1993-1996 Id Software, Inc.
   5 // Copyright(C) 2005 Simon Howard
   6 //
   7 // This program is free software; you can redistribute it and/or
   8 // modify it under the terms of the GNU General Public License
   9 // as published by the Free Software Foundation; either version 2
  10 // of the License, or (at your option) any later version.
  11 //
  12 // This program is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16 //
  17 // You should have received a copy of the GNU General Public License
  18 // along with this program; if not, write to the Free Software
  19 // Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  20 // 02111-1307, USA.
  21 //
  22 // DESCRIPTION:
  23 //      Lookup tables.
  24 //      Do not try to look them up :-).
  25 //      In the order of appearance:
  26 //
  27 //      int finetangent[4096]   - Tangens LUT.
  28 //       Should work with BAM fairly well (12 of 16bit,
  29 //      effectively, by shifting).
  30 //
  31 //      int finesine[10240]             - Sine lookup.
  32 //       Guess what, serves as cosine, too.
  33 //       Remarkable thing is, how to use BAMs with this?
  34 //
  35 //      int tantoangle[2049]    - ArcTan LUT,
  36 //        maps tan(angle) to angle fast. Gotta search.
  37 //
  38 //-----------------------------------------------------------------------------
  39
  40
  41 #ifndef __TABLES__
  42 #define __TABLES__
  43
  44
  45
  46 #include "m_fixed.h"
  47
  48 #define FINEANGLES              8192
  49 #define FINEMASK                (FINEANGLES-1)
  50
  51
  52 // 0x100000000 to 0x2000
  53 #define ANGLETOFINESHIFT        19
  54
  55 // Effective size is 10240.
  56 extern const fixed_t finesine[5*FINEANGLES/4];
  57
  58 // Re-use data, is just PI/2 pahse shift.
  59 extern const fixed_t *finecosine;
  60
  61
  62 // Effective size is 4096.
  63 extern const fixed_t finetangent[FINEANGLES/2];
  64
  65 // Binary Angle Measument, BAM.
  66 #define ANG45                   0x20000000
  67 #define ANG90                   0x40000000
  68 #define ANG180          0x80000000
  69 #define ANG270          0xc0000000
  70
  71
  72 #define SLOPERANGE              2048
  73 #define SLOPEBITS               11
  74 #define DBITS                   (FRACBITS-SLOPEBITS)
  75
  76 typedef unsigned angle_t;
  77
  78
  79 // Effective size is 2049;
  80 // The +1 size is to handle the case when x==y
  81 //  without additional checking.
  82 extern const angle_t tantoangle[SLOPERANGE+1];
  83
  84
  85 // Utility function,
  86 //  called by R_PointToAngle.
  87 int
  88 SlopeDiv
  89 ( unsigned      num,
  90   unsigned      den);
  91
  92
  93 #endif
  94