WebSVN – gelsvn – Diff – /trunk/src/CGLA/TableTrigonometry.h


/* ----------------------------------------------------------------------- *
 * This file is part of GEL, http://www.imm.dtu.dk/GEL
 * Copyright (C) the authors and DTU Informatics
 * For license and list of authors, see ../../doc/intro.pdf
 * ----------------------------------------------------------------------- */
 
/** @file TableTrigonometry.h
 * @brief Tabulated trigonometry - not certain this is useful.
 */
 
#ifndef __CGLA_TABLETRIGONOMETRY_H__
#define __CGLA_TABLETRIGONOMETRY_H__
 
#include <vector>
#include "CGLA.h"
 
namespace CGLA {
 
	namespace TableTrigonometry
	{
		typedef unsigned short int Angle;
 
		const Angle  ANGLE_MAX = USHRT_MAX>>2;
		const float ANGLE_FACTOR = float(ANGLE_MAX) / M_PI_2;
	
		class CosTable
		{
			std::vector<float> tab;
 
		public:
		
			CosTable(): tab(ANGLE_MAX+1)
			{
				for(int i=0;i<ANGLE_MAX+1; i++)
					tab[i] = cos(i/ANGLE_FACTOR);
			}
		
			float operator[](int i) const {return tab[i];}
		};
 
		const CosTable& COS_TABLE();
 
		inline float angle2float(Angle theta)
		{
			static float MPI2 = (float)(M_PI * 2);
			switch(theta & 3)
				{
				case 0: return   (theta>>2)/ANGLE_FACTOR;
				case 1: return M_PI - (theta>>2)/ANGLE_FACTOR;
				case 2: return M_PI + (theta>>2)/ANGLE_FACTOR;
				case 3: return MPI2 - (theta>>2)/ANGLE_FACTOR;
				}
			return 0;	
		}
 
		inline float t_cos(Angle theta)
		{
			switch(theta & 3)
				{
				case 0: return   COS_TABLE()[ theta>>2 ];
				case 1: return - COS_TABLE()[ theta>>2 ];
				case 2: return - COS_TABLE()[ theta>>2 ];
				case 3: return   COS_TABLE()[ theta>>2 ];
				}
			return 0;
		}
 
		inline float t_sin(Angle theta)
		{
			switch(theta & 3)
				{
				case 0: return   COS_TABLE()[ ANGLE_MAX - (theta>>2) ];
				case 1: return   COS_TABLE()[ ANGLE_MAX - (theta>>2) ];
				case 2: return - COS_TABLE()[ ANGLE_MAX - (theta>>2) ];
				case 3: return - COS_TABLE()[ ANGLE_MAX - (theta>>2) ];
				}
			return 0;
		}
 
		inline Angle t_atan(float x, float y)
		{
			Angle theta = Angle( acos(fabs(x)/sqrt(x*x+y*y)) * ANGLE_FACTOR );
			Angle key = (x>=0 ? (y>=0 ? 0 : 3) : (y>=0 ? 1 : 2));
			return (theta<<2) | key;
		}
 
	}
 
 
}
#endif
 

Rev 2	Rev 595
-		1	`/* ----------------------------------------------------------------------- *`
-		2	`* This file is part of GEL, http://www.imm.dtu.dk/GEL`
-		3	`* Copyright (C) the authors and DTU Informatics`
-		4	`* For license and list of authors, see ../../doc/intro.pdf`
-		5	`* ----------------------------------------------------------------------- */`
-		6
-		7	`/** @file TableTrigonometry.h`
-		8	`* @brief Tabulated trigonometry - not certain this is useful.`
-		9	`*/`
-		10
1	`#ifndef __CGLA_TABLETRIGONOMETRY_H__`	11	`#ifndef __CGLA_TABLETRIGONOMETRY_H__`
2	`#define __CGLA_TABLETRIGONOMETRY_H__`	12	`#define __CGLA_TABLETRIGONOMETRY_H__`
3		13
4	`#include <vector>`	14	`#include <vector>`
5	`#include "CGLA.h"`	15	`#include "CGLA.h"`
6		16
7	`namespace CGLA {`	17	`namespace CGLA {`
8		18
9	`namespace TableTrigonometry`	19	`namespace TableTrigonometry`
10	`{`	20	`{`
11	`typedef unsigned short int Angle;`	21	`typedef unsigned short int Angle;`
12		22
13	`const Angle ANGLE_MAX = USHRT_MAX>>2;`	23	`const Angle ANGLE_MAX = USHRT_MAX>>2;`
14	`const float ANGLE_FACTOR = float(ANGLE_MAX) / M_PI_2;`	24	`const float ANGLE_FACTOR = float(ANGLE_MAX) / M_PI_2;`
15		25
16	`class CosTable`	26	`class CosTable`
17	`{`	27	`{`
18	`std::vector<float> tab;`	28	`std::vector<float> tab;`
19		29
20	`public:`	30	`public:`
21		31
22	`CosTable(): tab(ANGLE_MAX+1)`	32	`CosTable(): tab(ANGLE_MAX+1)`
23	`{`	33	`{`
24	`for(int i=0;i<ANGLE_MAX+1; i++)`	34	`for(int i=0;i<ANGLE_MAX+1; i++)`
25	`tab[i] = cos(i/ANGLE_FACTOR);`	35	`tab[i] = cos(i/ANGLE_FACTOR);`
26	`}`	36	`}`
27		37
28	`float operator[](int i) const {return tab[i];}`	38	`float operator[](int i) const {return tab[i];}`
29	`};`	39	`};`
30		40
31	`const CosTable& COS_TABLE();`	41	`const CosTable& COS_TABLE();`
32		42
33	`inline float angle2float(Angle theta)`	43	`inline float angle2float(Angle theta)`
34	`{`	44	`{`
35	`static float MPI2 = (float)(M_PI * 2);`	45	`static float MPI2 = (float)(M_PI * 2);`
36	`switch(theta & 3)`	46	`switch(theta & 3)`
37	`{`	47	`{`
38	`case 0: return (theta>>2)/ANGLE_FACTOR;`	48	`case 0: return (theta>>2)/ANGLE_FACTOR;`
39	`case 1: return M_PI - (theta>>2)/ANGLE_FACTOR;`	49	`case 1: return M_PI - (theta>>2)/ANGLE_FACTOR;`
40	`case 2: return M_PI + (theta>>2)/ANGLE_FACTOR;`	50	`case 2: return M_PI + (theta>>2)/ANGLE_FACTOR;`
41	`case 3: return MPI2 - (theta>>2)/ANGLE_FACTOR;`	51	`case 3: return MPI2 - (theta>>2)/ANGLE_FACTOR;`
42	`}`	52	`}`
43	`return 0;`	53	`return 0;`
44	`}`	54	`}`
45		55
46	`inline float t_cos(Angle theta)`	56	`inline float t_cos(Angle theta)`
47	`{`	57	`{`
48	`switch(theta & 3)`	58	`switch(theta & 3)`
49	`{`	59	`{`
50	`case 0: return COS_TABLE()[ theta>>2 ];`	60	`case 0: return COS_TABLE()[ theta>>2 ];`
51	`case 1: return - COS_TABLE()[ theta>>2 ];`	61	`case 1: return - COS_TABLE()[ theta>>2 ];`
52	`case 2: return - COS_TABLE()[ theta>>2 ];`	62	`case 2: return - COS_TABLE()[ theta>>2 ];`
53	`case 3: return COS_TABLE()[ theta>>2 ];`	63	`case 3: return COS_TABLE()[ theta>>2 ];`
54	`}`	64	`}`
55	`return 0;`	65	`return 0;`
56	`}`	66	`}`
57		67
58	`inline float t_sin(Angle theta)`	68	`inline float t_sin(Angle theta)`
59	`{`	69	`{`
60	`switch(theta & 3)`	70	`switch(theta & 3)`
61	`{`	71	`{`
62	`case 0: return COS_TABLE()[ ANGLE_MAX - (theta>>2) ];`	72	`case 0: return COS_TABLE()[ ANGLE_MAX - (theta>>2) ];`
63	`case 1: return COS_TABLE()[ ANGLE_MAX - (theta>>2) ];`	73	`case 1: return COS_TABLE()[ ANGLE_MAX - (theta>>2) ];`
64	`case 2: return - COS_TABLE()[ ANGLE_MAX - (theta>>2) ];`	74	`case 2: return - COS_TABLE()[ ANGLE_MAX - (theta>>2) ];`
65	`case 3: return - COS_TABLE()[ ANGLE_MAX - (theta>>2) ];`	75	`case 3: return - COS_TABLE()[ ANGLE_MAX - (theta>>2) ];`
66	`}`	76	`}`
67	`return 0;`	77	`return 0;`
68	`}`	78	`}`
69		79
70	`inline Angle t_atan(float x, float y)`	80	`inline Angle t_atan(float x, float y)`
71	`{`	81	`{`
72	`Angle theta = Angle( acos(fabs(x)/sqrt(xx+yy)) * ANGLE_FACTOR );`	82	`Angle theta = Angle( acos(fabs(x)/sqrt(xx+yy)) * ANGLE_FACTOR );`
73	`Angle key = (x>=0 ? (y>=0 ? 0 : 3) : (y>=0 ? 1 : 2));`	83	`Angle key = (x>=0 ? (y>=0 ? 0 : 3) : (y>=0 ? 1 : 2));`
74	`return (theta<<2) \| key;`	84	`return (theta<<2) \| key;`
75	`}`	85	`}`
76		86
77	`}`	87	`}`
78		88
79		89
80	`}`	90	`}`
81	`#endif`	91	`#endif`
82		92

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(root)/trunk/src/CGLA/TableTrigonometry.h – Rev 2 → 595