/********************************************************************************
						   NINTENDO64 Disk Drive IPL4

							  math function module

								December 11, 1996
 ********************************************************************************/

#include <ultra64.h>
#include "ipl4.h"
#include "graphics.h"


#define	DEG000		0x0000
#define	DEG090		0x4000
#define	DEG180		0x8000
#define	DEG270		0xC000
#define	DEG360		0x0000


//////////////////////////////////////////////////////////////////////////////////
//
//
//
//
//		Convert number
//
//
//
//
//////////////////////////////////////////////////////////////////////////////////

/********************************************************************************/
/*																				*/
/*	Convert BCD to binary.														*/
/*																				*/
/********************************************************************************/
extern int
BcdToBin(int bcd)
{
	return(((bcd >> 4) * 10) + (bcd & 0x0f));
}
/********************************************************************************/
/*																				*/
/*	Convert banary to BCD.														*/
/*																				*/
/********************************************************************************/
extern int
BinToBcd(int bin)
{
	return(((bin / 10) << 4) | (bin % 10));
}


//////////////////////////////////////////////////////////////////////////////////
//
//
//
//
//		3D vector functions
//
//
//
//
//////////////////////////////////////////////////////////////////////////////////

/********************************************************************************/
/*																				*/
/*	Set a floating point 3D vector.												*/
/*																				*/
/********************************************************************************/
extern void
SetFVector(FVector *vector, float x, float y, float z)
{
	vector->x = x;
	vector->y = y;
	vector->z = z;
}
/********************************************************************************/
/*																				*/
/*	Set a short 3D vector.														*/
/*																				*/
/********************************************************************************/
extern void
SetSVector(SVector *vector, float x, float y, float z)
{
	vector->x = x;
	vector->y = y;
	vector->z = z;
}
/********************************************************************************/
/*																				*/
/*	Set a RGBA color.															*/
/*																				*/
/********************************************************************************/
extern void
SetRGBAColor(RGBAColor *color, uchar r, uchar g, uchar b, uchar a)
{
	color->r = r;
	color->g = g;
	color->b = b;
	color->a = a;
}
/********************************************************************************/
/*																				*/
/*	Normalize vector.															*/
/*																				*/
/********************************************************************************/
extern void
NormalizeFVector(FVector *vector)
{
	float length = sqrtf(vector->x*vector->x + vector->y*vector->y + vector->z*vector->z);

	if (length > 0.0f) {
		vector->x /= length;
		vector->y /= length;
		vector->z /= length;
	}
}


//////////////////////////////////////////////////////////////////////////////////
//
//
//
//
//		Angle convertion functions
//
//
//
//
//////////////////////////////////////////////////////////////////////////////////

/********************************************************************************/
/*																				*/
/*	Convert Angle to Radian.													*/
/*																				*/
/********************************************************************************/
extern float
AngleToRadian(short angle)
{
	return((float)angle * M_PI / 32768.0f);
}
/********************************************************************************/
/*																				*/
/*	Convert Degree to Radian.													*/
/*																				*/
/********************************************************************************/
extern float
DegreeToRadian(float degree)
{
	return(degree * M_PI / 180.0f);
}
/********************************************************************************/
/*																				*/
/*	Convert an angle vector to a radian vector.									*/
/*																				*/
/********************************************************************************/
extern void
AngvecToRadvec(FVector *radvec, SVector *angvec)
{
	radvec->x = AngleToRadian(angvec->x);
	radvec->y = AngleToRadian(angvec->y);
	radvec->z = AngleToRadian(angvec->z);
}


//////////////////////////////////////////////////////////////////////////////////
//
//
//
//
//		Matrix creators
//
//
//
//
//////////////////////////////////////////////////////////////////////////////////

/********************************************************************************/
/*																				*/
/*	Store an Affine matrix into a Mtx.											*/
/*																				*/
/********************************************************************************/
extern void
AffineToMtx(Mtx *matrix, AffineMtx *affine)
{
	SPacked data;
	register int	count;
	register short	*integer  = (short *)&(matrix->m[0][0]);
	register short	*fraction = (short *)&(matrix->m[2][0]);
	register float	*real	  = (float *)&((*affine)[0][0]);


	for (count = 0; count < 16; count++) {
		data.word	= (long)((*real++) * 65536.0f);
		*integer++  = data.half[0];
		*fraction++ = data.half[1];
	}
}
/********************************************************************************/
/*																				*/
/*	Create a modeling matrix.													*/
/*																				*/
/********************************************************************************/
extern void
CreateModelAffineMtx(AffineMtx *affine, FVector *position, FVector *angle, FVector *scaling)
{
	register float sinA = sinf(angle->x);
	register float cosA = cosf(angle->x);
	register float sinB = sinf(angle->y);
	register float cosB = cosf(angle->y);
	register float sinC = sinf(angle->z);
	register float cosC = cosf(angle->z);


	(*affine)[0][0] = scaling->x *  cosB * cosC + sinA * sinB * sinC;
	(*affine)[0][1] = scaling->x *  cosA * sinC;
	(*affine)[0][2] = scaling->x * -sinB * cosC + sinA * cosB * sinC;
	(*affine)[0][3] = 0.0f;

	(*affine)[1][0] = scaling->y * -cosB * sinC + sinA * sinB * cosC;
	(*affine)[1][1] = scaling->y *  cosA * cosC;
	(*affine)[1][2] = scaling->y *  sinB * sinC + sinA * cosB * cosC;
	(*affine)[1][3] = 0.0f;

	(*affine)[2][0] = scaling->z *  cosA * sinB;
	(*affine)[2][1] = scaling->z * -sinA;
	(*affine)[2][2] = scaling->z *  cosA * cosB;
	(*affine)[2][3] = 0.0f;

	(*affine)[3][0] = position->x;
	(*affine)[3][1] = position->y;
	(*affine)[3][2] = position->z;
	(*affine)[3][3] = 1.0f;
}
/********************************************************************************/
/*																				*/
/*	Create a modeling matrix.													*/
/*																				*/
/********************************************************************************/
extern void
CreateModelMatrix(Mtx *matrix, FVector *position, FVector *angle, FVector *scaling)
{
	AffineMtx affine;

	CreateModelAffineMtx(&affine, position, angle, scaling);
	AffineToMtx(matrix, &affine);
}
/********************************************************************************/
/*																				*/
/*	Create a skeleton joint matrix.												*/
/*																				*/
/********************************************************************************/
extern void
CreateJointMatrix(Mtx *matrix, FVector *position, FVector *angle)
{
	AffineMtx affine;

	register float sinX = sinf(angle->x);
	register float cosX = cosf(angle->x);
	register float sinY = sinf(angle->y);
	register float cosY = cosf(angle->y);
	register float sinZ = sinf(angle->z);
	register float cosZ = cosf(angle->z);


	affine[0][0] =  cosY * cosZ;
	affine[0][1] =  cosY * sinZ;
	affine[0][2] = -sinY;
	affine[0][3] =  0.0f;

	affine[1][0] =  sinX * sinY * cosZ - cosX * sinZ;
	affine[1][1] =  sinX * sinY * sinZ + cosX * cosZ;
	affine[1][2] =  sinX * cosY;
	affine[1][3] =  0.0f;

	affine[2][0] =  cosX * sinY * cosZ + sinX * sinZ;
	affine[2][1] =  cosX * sinY * sinZ - sinX * cosZ;
	affine[2][2] =  cosX * cosY;
	affine[2][3] =  0.0f;

	affine[3][0] =  position->x;
	affine[3][1] =  position->y;
	affine[3][2] =  position->z;
	affine[3][3] =  1.0f;

	AffineToMtx(matrix, &affine);
}
/********************************************************************************/
/*																				*/
/*	Rotate a point.																*/
/*																				*/
/********************************************************************************/
extern void
DoRotation(AffineMtx *mtx, FVector *pnt)
{
	register float x = pnt->x;
	register float y = pnt->y;
	register float z = pnt->z;

	pnt->x = x * (*mtx)[0][0] + y * (*mtx)[1][0] + z * (*mtx)[2][0] + (*mtx)[3][0];
	pnt->y = x * (*mtx)[0][1] + y * (*mtx)[1][1] + z * (*mtx)[2][1] + (*mtx)[3][1];
	pnt->z = x * (*mtx)[0][2] + y * (*mtx)[1][2] + z * (*mtx)[2][2] + (*mtx)[3][2];
}


//////////////////////////////////////////////////////////////////////////////////
//
//
//
//
//		Random funcions
//
//
//
//
//////////////////////////////////////////////////////////////////////////////////

/********************************************************************************/
/*																				*/
/*	Random (short).																*/
/*																				*/
/********************************************************************************/
extern ushort
Randomi(void)
{
	return(guRandom() & 0xffff);
}
/********************************************************************************/
/*																				*/
/*	Random (float).																*/
/*																				*/
/********************************************************************************/
extern float
Randomf(void)
{
	int rand = Randomi();

	return((float)rand / 65536.0f);
}


//////////////////////////////////////////////////////////////////////////////////
//
//
//
//
//		Arc tangent
//
//
//
//
//////////////////////////////////////////////////////////////////////////////////

/********************************************************************************/
/*																				*/
/*	ATAN table.																	*/
/*																				*/
/********************************************************************************/

static unsigned short atanTable[] = {
	0x0000, 0x000A, 0x0014, 0x001F, 0x0029, 0x0033, 0x003D, 0x0047,	0x0051, 0x005C, 0x0066, 0x0070, 0x007A, 0x0084, 0x008F, 0x0099,
	0x00A3, 0x00AD, 0x00B7, 0x00C2, 0x00CC, 0x00D6, 0x00E0, 0x00EA,	0x00F4, 0x00FF, 0x0109, 0x0113, 0x011D, 0x0127, 0x0131, 0x013C,
	0x0146, 0x0150, 0x015A, 0x0164, 0x016F, 0x0179, 0x0183, 0x018D,	0x0197, 0x01A1, 0x01AC, 0x01B6, 0x01C0, 0x01CA, 0x01D4, 0x01DE,
	0x01E9, 0x01F3, 0x01FD, 0x0207, 0x0211, 0x021B, 0x0226, 0x0230,	0x023A, 0x0244, 0x024E, 0x0258, 0x0262, 0x026D, 0x0277, 0x0281,
	0x028B, 0x0295, 0x029F, 0x02A9, 0x02B4, 0x02BE, 0x02C8, 0x02D2,	0x02DC, 0x02E6, 0x02F0, 0x02FB, 0x0305, 0x030F, 0x0319, 0x0323,
	0x032D, 0x0337, 0x0341, 0x034C, 0x0356, 0x0360, 0x036A, 0x0374,	0x037E, 0x0388, 0x0392, 0x039C, 0x03A7, 0x03B1, 0x03BB, 0x03C5,
	0x03CF, 0x03D9, 0x03E3, 0x03ED, 0x03F7, 0x0401, 0x040C, 0x0416,	0x0420, 0x042A, 0x0434, 0x043E, 0x0448, 0x0452, 0x045C, 0x0466,
	0x0470, 0x047A, 0x0484, 0x048E, 0x0499, 0x04A3, 0x04AD, 0x04B7,	0x04C1, 0x04CB, 0x04D5, 0x04DF, 0x04E9, 0x04F3, 0x04FD, 0x0507,
	0x0511, 0x051B, 0x0525, 0x052F, 0x0539, 0x0543, 0x054D, 0x0557,	0x0561, 0x056B, 0x0575, 0x057F, 0x0589, 0x0593, 0x059D, 0x05A7,
	0x05B1, 0x05BB, 0x05C5, 0x05CF, 0x05D9, 0x05E3, 0x05ED, 0x05F7,	0x0601, 0x060B, 0x0615, 0x061F, 0x0629, 0x0633, 0x063D, 0x0647,
	0x0651, 0x065B, 0x0665, 0x066E, 0x0678, 0x0682, 0x068C, 0x0696,	0x06A0, 0x06AA, 0x06B4, 0x06BE, 0x06C8, 0x06D2, 0x06DC, 0x06E5,
	0x06EF, 0x06F9, 0x0703, 0x070D, 0x0717, 0x0721, 0x072B, 0x0735,	0x073E, 0x0748, 0x0752, 0x075C, 0x0766, 0x0770, 0x077A, 0x0783,
	0x078D, 0x0797, 0x07A1, 0x07AB, 0x07B5, 0x07BE, 0x07C8, 0x07D2,	0x07DC, 0x07E6, 0x07EF, 0x07F9, 0x0803, 0x080D, 0x0817, 0x0820,
	0x082A, 0x0834, 0x083E, 0x0848, 0x0851, 0x085B, 0x0865, 0x086F,	0x0878, 0x0882, 0x088C, 0x0896, 0x089F, 0x08A9, 0x08B3, 0x08BD,
	0x08C6, 0x08D0, 0x08DA, 0x08E3, 0x08ED, 0x08F7, 0x0901, 0x090A,	0x0914, 0x091E, 0x0927, 0x0931, 0x093B, 0x0944, 0x094E, 0x0958,
	0x0961, 0x096B, 0x0975, 0x097E, 0x0988, 0x0992, 0x099B, 0x09A5,	0x09AE, 0x09B8, 0x09C2, 0x09CB, 0x09D5, 0x09DE, 0x09E8, 0x09F2,
	0x09FB, 0x0A05, 0x0A0E, 0x0A18, 0x0A22, 0x0A2B, 0x0A35, 0x0A3E,	0x0A48, 0x0A51, 0x0A5B, 0x0A64, 0x0A6E, 0x0A77, 0x0A81, 0x0A8B,
	0x0A94, 0x0A9E, 0x0AA7, 0x0AB1, 0x0ABA, 0x0AC4, 0x0ACD, 0x0AD7,	0x0AE0, 0x0AE9, 0x0AF3, 0x0AFC, 0x0B06, 0x0B0F, 0x0B19, 0x0B22,
	0x0B2C, 0x0B35, 0x0B3F, 0x0B48, 0x0B51, 0x0B5B, 0x0B64, 0x0B6E,	0x0B77, 0x0B80, 0x0B8A, 0x0B93, 0x0B9D, 0x0BA6, 0x0BAF, 0x0BB9,
	0x0BC2, 0x0BCB, 0x0BD5, 0x0BDE, 0x0BE7, 0x0BF1, 0x0BFA, 0x0C03,	0x0C0D, 0x0C16, 0x0C1F, 0x0C29, 0x0C32, 0x0C3B, 0x0C45, 0x0C4E,
	0x0C57, 0x0C60, 0x0C6A, 0x0C73, 0x0C7C, 0x0C86, 0x0C8F, 0x0C98,	0x0CA1, 0x0CAB, 0x0CB4, 0x0CBD, 0x0CC6, 0x0CCF, 0x0CD9, 0x0CE2,
	0x0CEB, 0x0CF4, 0x0CFD, 0x0D07, 0x0D10, 0x0D19, 0x0D22, 0x0D2B,	0x0D34, 0x0D3E, 0x0D47, 0x0D50, 0x0D59, 0x0D62, 0x0D6B, 0x0D74,
	0x0D7D, 0x0D87, 0x0D90, 0x0D99, 0x0DA2, 0x0DAB, 0x0DB4, 0x0DBD,	0x0DC6, 0x0DCF, 0x0DD8, 0x0DE1, 0x0DEA, 0x0DF3, 0x0DFC, 0x0E05,
	0x0E0F, 0x0E18, 0x0E21, 0x0E2A, 0x0E33, 0x0E3C, 0x0E45, 0x0E4E,	0x0E56, 0x0E5F, 0x0E68, 0x0E71, 0x0E7A, 0x0E83, 0x0E8C, 0x0E95,
	0x0E9E, 0x0EA7, 0x0EB0, 0x0EB9, 0x0EC2, 0x0ECB, 0x0ED4, 0x0EDC,	0x0EE5, 0x0EEE, 0x0EF7, 0x0F00, 0x0F09, 0x0F12, 0x0F1B, 0x0F23,
	0x0F2C, 0x0F35, 0x0F3E, 0x0F47, 0x0F50, 0x0F58, 0x0F61, 0x0F6A,	0x0F73, 0x0F7C, 0x0F84, 0x0F8D, 0x0F96, 0x0F9F, 0x0FA7, 0x0FB0,
	0x0FB9, 0x0FC2, 0x0FCA, 0x0FD3, 0x0FDC, 0x0FE5, 0x0FED, 0x0FF6,	0x0FFF, 0x1007, 0x1010, 0x1019, 0x1021, 0x102A, 0x1033, 0x103B,
	0x1044, 0x104D, 0x1055, 0x105E, 0x1067, 0x106F, 0x1078, 0x1080,	0x1089, 0x1092, 0x109A, 0x10A3, 0x10AB, 0x10B4, 0x10BC, 0x10C5,
	0x10CE, 0x10D6, 0x10DF, 0x10E7, 0x10F0, 0x10F8, 0x1101, 0x1109,	0x1112, 0x111A, 0x1123, 0x112B, 0x1134, 0x113C, 0x1145, 0x114D,
	0x1156, 0x115E, 0x1166, 0x116F, 0x1177, 0x1180, 0x1188, 0x1191,	0x1199, 0x11A1, 0x11AA, 0x11B2, 0x11BB, 0x11C3, 0x11CB, 0x11D4,
	0x11DC, 0x11E4, 0x11ED, 0x11F5, 0x11FD, 0x1206, 0x120E, 0x1216,	0x121F, 0x1227, 0x122F, 0x1237, 0x1240, 0x1248, 0x1250, 0x1259,
	0x1261, 0x1269, 0x1271, 0x127A, 0x1282, 0x128A, 0x1292, 0x129A,	0x12A3, 0x12AB, 0x12B3, 0x12BB, 0x12C3, 0x12CC, 0x12D4, 0x12DC,
	0x12E4, 0x12EC, 0x12F4, 0x12FC, 0x1305, 0x130D, 0x1315, 0x131D,	0x1325, 0x132D, 0x1335, 0x133D, 0x1345, 0x134D, 0x1355, 0x135E,
	0x1366, 0x136E, 0x1376, 0x137E, 0x1386, 0x138E, 0x1396, 0x139E,	0x13A6, 0x13AE, 0x13B6, 0x13BE, 0x13C6, 0x13CE, 0x13D6, 0x13DE,
	0x13E6, 0x13ED, 0x13F5, 0x13FD, 0x1405, 0x140D, 0x1415, 0x141D,	0x1425, 0x142D, 0x1435, 0x143D, 0x1444, 0x144C, 0x1454, 0x145C,
	0x1464, 0x146C, 0x1473, 0x147B, 0x1483, 0x148B, 0x1493, 0x149B,	0x14A2, 0x14AA, 0x14B2, 0x14BA, 0x14C1, 0x14C9, 0x14D1, 0x14D9,
	0x14E0, 0x14E8, 0x14F0, 0x14F8, 0x14FF, 0x1507, 0x150F, 0x1516,	0x151E, 0x1526, 0x152D, 0x1535, 0x153D, 0x1544, 0x154C, 0x1554,
	0x155B, 0x1563, 0x156B, 0x1572, 0x157A, 0x1581, 0x1589, 0x1591,	0x1598, 0x15A0, 0x15A7, 0x15AF, 0x15B7, 0x15BE, 0x15C6, 0x15CD,
	0x15D5, 0x15DC, 0x15E4, 0x15EB, 0x15F3, 0x15FA, 0x1602, 0x1609,	0x1611, 0x1618, 0x1620, 0x1627, 0x162F, 0x1636, 0x163E, 0x1645,
	0x164C, 0x1654, 0x165B, 0x1663, 0x166A, 0x1671, 0x1679, 0x1680,	0x1688, 0x168F, 0x1696, 0x169E, 0x16A5, 0x16AC, 0x16B4, 0x16BB,
	0x16C2, 0x16CA, 0x16D1, 0x16D8, 0x16E0, 0x16E7, 0x16EE, 0x16F6,	0x16FD, 0x1704, 0x170B, 0x1713, 0x171A, 0x1721, 0x1728, 0x1730,
	0x1737, 0x173E, 0x1745, 0x174C, 0x1754, 0x175B, 0x1762, 0x1769,	0x1770, 0x1778, 0x177F, 0x1786, 0x178D, 0x1794, 0x179B, 0x17A2,
	0x17AA, 0x17B1, 0x17B8, 0x17BF, 0x17C6, 0x17CD, 0x17D4, 0x17DB,	0x17E2, 0x17E9, 0x17F0, 0x17F7, 0x17FE, 0x1806, 0x180D, 0x1814,
	0x181B, 0x1822, 0x1829, 0x1830, 0x1837, 0x183E, 0x1845, 0x184C,	0x1853, 0x185A, 0x1860, 0x1867, 0x186E, 0x1875, 0x187C, 0x1883,
	0x188A, 0x1891, 0x1898, 0x189F, 0x18A6, 0x18AD, 0x18B3, 0x18BA,	0x18C1, 0x18C8, 0x18CF, 0x18D6, 0x18DD, 0x18E3, 0x18EA, 0x18F1,
	0x18F8, 0x18FF, 0x1906, 0x190C, 0x1913, 0x191A, 0x1921, 0x1928,	0x192E, 0x1935, 0x193C, 0x1943, 0x1949, 0x1950, 0x1957, 0x195D,
	0x1964, 0x196B, 0x1972, 0x1978, 0x197F, 0x1986, 0x198C, 0x1993,	0x199A, 0x19A0, 0x19A7, 0x19AE, 0x19B4, 0x19BB, 0x19C2, 0x19C8,
	0x19CF, 0x19D5, 0x19DC, 0x19E3, 0x19E9, 0x19F0, 0x19F6, 0x19FD,	0x1A04, 0x1A0A, 0x1A11, 0x1A17, 0x1A1E, 0x1A24, 0x1A2B, 0x1A31,
	0x1A38, 0x1A3E, 0x1A45, 0x1A4B, 0x1A52, 0x1A58, 0x1A5F, 0x1A65,	0x1A6C, 0x1A72, 0x1A79, 0x1A7F, 0x1A86, 0x1A8C, 0x1A93, 0x1A99,
	0x1A9F, 0x1AA6, 0x1AAC, 0x1AB3, 0x1AB9, 0x1AC0, 0x1AC6, 0x1ACC,	0x1AD3, 0x1AD9, 0x1ADF, 0x1AE6, 0x1AEC, 0x1AF2, 0x1AF9, 0x1AFF,
	0x1B05, 0x1B0C, 0x1B12, 0x1B18, 0x1B1F, 0x1B25, 0x1B2B, 0x1B32,	0x1B38, 0x1B3E, 0x1B44, 0x1B4B, 0x1B51, 0x1B57, 0x1B5D, 0x1B64,
	0x1B6A, 0x1B70, 0x1B76, 0x1B7D, 0x1B83, 0x1B89, 0x1B8F, 0x1B95,	0x1B9C, 0x1BA2, 0x1BA8, 0x1BAE, 0x1BB4, 0x1BBA, 0x1BC1, 0x1BC7,
	0x1BCD, 0x1BD3, 0x1BD9, 0x1BDF, 0x1BE5, 0x1BEB, 0x1BF2, 0x1BF8,	0x1BFE, 0x1C04, 0x1C0A, 0x1C10, 0x1C16, 0x1C1C, 0x1C22, 0x1C28,
	0x1C2E, 0x1C34, 0x1C3A, 0x1C40, 0x1C46, 0x1C4C, 0x1C52, 0x1C58,	0x1C5E, 0x1C64, 0x1C6A, 0x1C70, 0x1C76, 0x1C7C, 0x1C82, 0x1C88,
	0x1C8E, 0x1C94, 0x1C9A, 0x1CA0, 0x1CA6, 0x1CAC, 0x1CB2, 0x1CB8,	0x1CBE, 0x1CC3, 0x1CC9, 0x1CCF, 0x1CD5, 0x1CDB, 0x1CE1, 0x1CE7,
	0x1CED, 0x1CF3, 0x1CF8, 0x1CFE, 0x1D04, 0x1D0A, 0x1D10, 0x1D16,	0x1D1B, 0x1D21, 0x1D27, 0x1D2D, 0x1D33, 0x1D38, 0x1D3E, 0x1D44,
	0x1D4A, 0x1D4F, 0x1D55, 0x1D5B, 0x1D61, 0x1D66, 0x1D6C, 0x1D72,	0x1D78, 0x1D7D, 0x1D83, 0x1D89, 0x1D8E, 0x1D94, 0x1D9A, 0x1DA0,
	0x1DA5, 0x1DAB, 0x1DB1, 0x1DB6, 0x1DBC, 0x1DC2, 0x1DC7, 0x1DCD,	0x1DD3, 0x1DD8, 0x1DDE, 0x1DE3, 0x1DE9, 0x1DEF, 0x1DF4, 0x1DFA,
	0x1DFF, 0x1E05, 0x1E0B, 0x1E10, 0x1E16, 0x1E1B, 0x1E21, 0x1E26,	0x1E2C, 0x1E32, 0x1E37, 0x1E3D, 0x1E42, 0x1E48, 0x1E4D, 0x1E53,
	0x1E58, 0x1E5E, 0x1E63, 0x1E69, 0x1E6E, 0x1E74, 0x1E79, 0x1E7F,	0x1E84, 0x1E8A, 0x1E8F, 0x1E94, 0x1E9A, 0x1E9F, 0x1EA5, 0x1EAA,
	0x1EB0, 0x1EB5, 0x1EBA, 0x1EC0, 0x1EC5, 0x1ECB, 0x1ED0, 0x1ED5,	0x1EDB, 0x1EE0, 0x1EE6, 0x1EEB, 0x1EF0, 0x1EF6, 0x1EFB, 0x1F00,
	0x1F06, 0x1F0B, 0x1F10, 0x1F16, 0x1F1B, 0x1F20, 0x1F26, 0x1F2B,	0x1F30, 0x1F36, 0x1F3B, 0x1F40, 0x1F45, 0x1F4B, 0x1F50, 0x1F55,
	0x1F5A, 0x1F60, 0x1F65, 0x1F6A, 0x1F6F, 0x1F75, 0x1F7A, 0x1F7F,	0x1F84, 0x1F8A, 0x1F8F, 0x1F94, 0x1F99, 0x1F9E, 0x1FA4, 0x1FA9,
	0x1FAE, 0x1FB3, 0x1FB8, 0x1FBD, 0x1FC3, 0x1FC8, 0x1FCD, 0x1FD2,	0x1FD7, 0x1FDC, 0x1FE1, 0x1FE6, 0x1FEC, 0x1FF1, 0x1FF6, 0x1FFB,
	0x2000
};

/********************************************************************************/
/*																				*/
/*	Get ATAN table.																*/
/*																				*/
/********************************************************************************/
static unsigned short
GetAtanTable(float a, float b)
{
	unsigned short angle;

	if (b == 0.0f) angle = atanTable[0];
			  else angle = atanTable[(int)(a/b * 1024.0f + 0.5f)];

	return(angle);
}
/********************************************************************************/
/*																				*/
/*	Calculate atan.																*/
/*																				*/
/********************************************************************************/
extern short
atan(float x, float y)
{
	unsigned short angle;

	if (y >= 0) {
		if (x >= 0) {
			if (x >= y) angle = DEG000 + GetAtanTable(y, x);
				   else angle = DEG090 - GetAtanTable(x, y);
		}
		else {
			x = -x;

			if (x < y) angle = DEG090 + GetAtanTable(x, y);
				  else angle = DEG180 - GetAtanTable(y, x);
		}
	}
	else {
		y = -y;

		if (x < 0) {
			x = -x;

			if (x >= y) angle = DEG180 + GetAtanTable(y, x);
				   else angle = DEG270 - GetAtanTable(x, y);
		}
		else {
			if (x < y) angle = DEG270 + GetAtanTable(x, y);
				  else angle = DEG360 - GetAtanTable(y, x);
		}
	}
	return((short)angle);
}