1  //
 2  // Copyright(C) 1993-1996 Id Software, Inc.
 3  // Copyright(C) 1993-2008 Raven Software
 4  // Copyright(C) 2005-2014 Simon Howard
 5  //
 6  // This program is free software; you can redistribute it and/or
 7  // modify it under the terms of the GNU General Public License
 8  // as published by the Free Software Foundation; either version 2
 9  // of the License, or (at your option) any later version.
10  //
11  // This program is distributed in the hope that it will be useful,
12  // but WITHOUT ANY WARRANTY; without even the implied warranty of
13  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  // GNU General Public License for more details.
15  //
16  // DESCRIPTION:
17  //	Lookup tables.
18  //	Do not try to look them up :-).
19  //	In the order of appearance: 
20  //
21  //	int finetangent[4096]	- Tangens LUT.
22  //	 Should work with BAM fairly well (12 of 16bit,
23  //      effectively, by shifting).
24  //
25  //	int finesine[10240]		- Sine lookup.
26  //	 Guess what, serves as cosine, too.
27  //	 Remarkable thing is, how to use BAMs with this? 
28  //
29  //	int tantoangle[2049]	- ArcTan LUT,
30  //	  maps tan(angle) to angle fast. Gotta search.	
31  //    
32  
33  
34  #ifndef __TABLES__
35  #define __TABLES__
36  
37  #include "doomtype.h"
38  
39  #include "m_fixed.h"
40  	
41  #define FINEANGLES		8192
42  #define FINEMASK		(FINEANGLES-1)
43  
44  
45  // 0x100000000 to 0x2000
46  #define ANGLETOFINESHIFT	19		
47  
48  // Effective size is 10240.
49  extern const fixed_t finesine[5*FINEANGLES/4];
50  
51  // Re-use data, is just PI/2 pahse shift.
52  extern const fixed_t *finecosine;
53  
54  
55  // Effective size is 4096.
56  extern const fixed_t finetangent[FINEANGLES/2];
57  
58  // Gamma correction tables.
59  extern const byte gammatable[5][256];
60  
61  // Binary Angle Measument, BAM.
62  
63  #define ANG45           0x20000000
64  #define ANG90           0x40000000
65  #define ANG180          0x80000000
66  #define ANG270          0xc0000000
67  #define ANG_MAX         0xffffffff
68  
69  #define ANG1            (ANG45 / 45)
70  #define ANG60           (ANG180 / 3)
71  
72  // Heretic code uses this definition as though it represents one 
73  // degree, but it is not!  This is actually ~1.40 degrees.
74  
75  #define ANG1_X          0x01000000
76  
77  #define SLOPERANGE		2048
78  #define SLOPEBITS		11
79  #define DBITS			(FRACBITS-SLOPEBITS)
80  
81  typedef unsigned angle_t;
82  
83  
84  // Effective size is 2049;
85  // The +1 size is to handle the case when x==y
86  //  without additional checking.
87  extern const angle_t tantoangle[SLOPERANGE+1];
88  
89  
90  // Utility function,
91  //  called by R_PointToAngle.
92  int SlopeDiv(unsigned int num, unsigned int den);
93  
94  
95  #endif
96