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123 lines
3 KiB
C++
123 lines
3 KiB
C++
// Emacs style mode select -*- C++ -*-
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//-----------------------------------------------------------------------------
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//
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// $Id:$
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//
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// Copyright (C) 1993-1996 by id Software, Inc.
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//
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// This source is available for distribution and/or modification
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// only under the terms of the DOOM Source Code License as
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// published by id Software. All rights reserved.
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//
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// The source is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// FITNESS FOR A PARTICULAR PURPOSE. See the DOOM Source Code License
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// for more details.
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//
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// DESCRIPTION:
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// Lookup tables.
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// Do not try to look them up :-).
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// In the order of appearance:
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//
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// int finetangent[4096] - Tangens LUT.
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// Should work with BAM fairly well (12 of 16bit,
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// effectively, by shifting).
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//
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// int finesine[10240] - Sine lookup.
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// Guess what, serves as cosine, too.
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// Remarkable thing is, how to use BAMs with this?
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//
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// int tantoangle[2049] - ArcTan LUT,
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// maps tan(angle) to angle fast. Gotta search.
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//
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//-----------------------------------------------------------------------------
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#ifndef __TABLES_H__
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#define __TABLES_H__
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#include <math.h>
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#ifndef PI
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#define PI 3.14159265358979323846 // matches value in gcc v2 math.h
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#endif
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#include "m_fixed.h"
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#define FINEANGLES 8192
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#define FINEMASK (FINEANGLES-1)
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// 0x100000000 to 0x2000
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#define ANGLETOFINESHIFT 19
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// Effective size is 10240.
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extern fixed_t finesine[5*FINEANGLES/4];
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// Re-use data, is just PI/2 phase shift.
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// [RH] Instead of using a pointer, use some inline code
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// (encapsulated in a struct so that we can still use array accesses).
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struct cosine_inline
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{
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fixed_t operator[] (unsigned int x)
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{
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return finesine[x+FINEANGLES/4];
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}
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};
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extern cosine_inline finecosine;
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// Effective size is 4096.
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extern fixed_t finetangent[FINEANGLES/2];
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// Binary Angle Measument, BAM.
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#define ANG45 (0x20000000)
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#define ANG90 (0x40000000)
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#define ANG180 (0x80000000)
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#define ANG270 (0xc0000000)
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#define ANGLE_45 (0x20000000)
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#define ANGLE_90 (0x40000000)
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#define ANGLE_180 (0x80000000)
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#define ANGLE_270 (0xc0000000)
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#define ANGLE_MAX (0xffffffff)
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#define ANGLE_1 (ANGLE_45/45)
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#define ANGLE_60 (ANGLE_180/3)
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#define SLOPERANGE 2048
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#define SLOPEBITS 11
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#define DBITS (FRACBITS-SLOPEBITS)
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typedef DWORD angle_t;
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// Avoid "ambiguous call to overloaded function" errors
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// Only to be used when you have subtracted two angles.
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#ifndef __GNUC__
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inline angle_t abs (angle_t ang)
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{
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return (angle_t)abs((SDWORD)ang);
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}
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#endif
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// Effective size is 2049;
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// The +1 size is to handle the case when x==y
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// without additional checking.
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extern angle_t tantoangle[SLOPERANGE+1];
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// Utility function,
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// called by R_PointToAngle.
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inline int SlopeDiv (unsigned int num, unsigned den)
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{
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unsigned int ans;
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if (den < 512)
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return SLOPERANGE;
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ans = (num << 3) / (den >> 8);
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return ans <= SLOPERANGE ? ans : SLOPERANGE;
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}
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#endif // __TABLES_H__
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