Quake-III-Arena/common/mathlib.c

/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.

This file is part of Quake III Arena source code.

Quake III Arena source code is free software; you can redistribute it
and/or modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the License,
or (at your option) any later version.

Quake III Arena source code is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Foobar; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/
// mathlib.c -- math primitives

#include "cmdlib.h"
#include "mathlib.h"

#ifdef _WIN32
//Improve floating-point consistency.
//without this option weird floating point issues occur
#pragma optimize( "p", on )
#endif


vec3_t vec3_origin = {0,0,0};

/*
** NormalToLatLong
**
** We use two byte encoded normals in some space critical applications.
** Lat = 0 at (1,0,0) to 360 (-1,0,0), encoded in 8-bit sine table format
** Lng = 0 at (0,0,1) to 180 (0,0,-1), encoded in 8-bit sine table format
**
*/
void NormalToLatLong( const vec3_t normal, byte bytes[2] ) {
	// check for singularities
	if ( normal[0] == 0 && normal[1] == 0 ) {
		if ( normal[2] > 0 ) {
			bytes[0] = 0;
			bytes[1] = 0;		// lat = 0, long = 0
		} else {
			bytes[0] = 128;
			bytes[1] = 0;		// lat = 0, long = 128
		}
	} else {
		int	a, b;

		a = RAD2DEG( atan2( normal[1], normal[0] ) ) * (255.0f / 360.0f );
		a &= 0xff;

		b = RAD2DEG( acos( normal[2] ) ) * ( 255.0f / 360.0f );
		b &= 0xff;

		bytes[0] = b;	// longitude
		bytes[1] = a;	// lattitude
	}
}

/*
=====================
PlaneFromPoints

Returns false if the triangle is degenrate.
The normal will point out of the clock for clockwise ordered points
=====================
*/
qboolean PlaneFromPoints( vec4_t plane, const vec3_t a, const vec3_t b, const vec3_t c ) {
	vec3_t	d1, d2;

	VectorSubtract( b, a, d1 );
	VectorSubtract( c, a, d2 );
	CrossProduct( d2, d1, plane );
	if ( VectorNormalize( plane, plane ) == 0 ) {
		return qfalse;
	}

	plane[3] = DotProduct( a, plane );
	return qtrue;
}

/*
================
MakeNormalVectors

Given a normalized forward vector, create two
other perpendicular vectors
================
*/
void MakeNormalVectors (vec3_t forward, vec3_t right, vec3_t up)
{
	float		d;

	// this rotate and negate guarantees a vector
	// not colinear with the original
	right[1] = -forward[0];
	right[2] = forward[1];
	right[0] = forward[2];

	d = DotProduct (right, forward);
	VectorMA (right, -d, forward, right);
	VectorNormalize (right, right);
	CrossProduct (right, forward, up);
}


void Vec10Copy( vec_t *in, vec_t *out ) {
	out[0] = in[0];
	out[1] = in[1];
	out[2] = in[2];
	out[3] = in[3];
	out[4] = in[4];
	out[5] = in[5];
	out[6] = in[6];
	out[7] = in[7];
	out[8] = in[8];
	out[9] = in[9];
}


void VectorRotate3x3( vec3_t v, float r[3][3], vec3_t d )
{
	d[0] = v[0] * r[0][0] + v[1] * r[1][0] + v[2] * r[2][0];
	d[1] = v[0] * r[0][1] + v[1] * r[1][1] + v[2] * r[2][1];
	d[2] = v[0] * r[0][2] + v[1] * r[1][2] + v[2] * r[2][2];
}

double VectorLength( const vec3_t v ) {
	int		i;
	double	length;
	
	length = 0;
	for (i=0 ; i< 3 ; i++)
		length += v[i]*v[i];
	length = sqrt (length);		// FIXME

	return length;
}

qboolean VectorCompare( const vec3_t v1, const vec3_t v2 ) {
	int		i;
	
	for (i=0 ; i<3 ; i++)
		if (fabs(v1[i]-v2[i]) > EQUAL_EPSILON)
			return qfalse;
			
	return qtrue;
}

vec_t Q_rint (vec_t in)
{
	return floor (in + 0.5);
}

void VectorMA( const vec3_t va, double scale, const vec3_t vb, vec3_t vc ) {
	vc[0] = va[0] + scale*vb[0];
	vc[1] = va[1] + scale*vb[1];
	vc[2] = va[2] + scale*vb[2];
}

void CrossProduct( const vec3_t v1, const vec3_t v2, vec3_t cross ) {
	cross[0] = v1[1]*v2[2] - v1[2]*v2[1];
	cross[1] = v1[2]*v2[0] - v1[0]*v2[2];
	cross[2] = v1[0]*v2[1] - v1[1]*v2[0];
}

vec_t _DotProduct (vec3_t v1, vec3_t v2)
{
	return v1[0]*v2[0] + v1[1]*v2[1] + v1[2]*v2[2];
}

void _VectorSubtract (vec3_t va, vec3_t vb, vec3_t out)
{
	out[0] = va[0]-vb[0];
	out[1] = va[1]-vb[1];
	out[2] = va[2]-vb[2];
}

void _VectorAdd (vec3_t va, vec3_t vb, vec3_t out)
{
	out[0] = va[0]+vb[0];
	out[1] = va[1]+vb[1];
	out[2] = va[2]+vb[2];
}

void _VectorCopy (vec3_t in, vec3_t out)
{
	out[0] = in[0];
	out[1] = in[1];
	out[2] = in[2];
}

void _VectorScale (vec3_t v, vec_t scale, vec3_t out)
{
	out[0] = v[0] * scale;
	out[1] = v[1] * scale;
	out[2] = v[2] * scale;
}

vec_t VectorNormalize( const vec3_t in, vec3_t out ) {
	vec_t	length, ilength;

	length = sqrt (in[0]*in[0] + in[1]*in[1] + in[2]*in[2]);
	if (length == 0)
	{
		VectorClear (out);
		return 0;
	}

	ilength = 1.0/length;
	out[0] = in[0]*ilength;
	out[1] = in[1]*ilength;
	out[2] = in[2]*ilength;

	return length;
}

vec_t ColorNormalize( const vec3_t in, vec3_t out ) {
	float	max, scale;

	max = in[0];
	if (in[1] > max)
		max = in[1];
	if (in[2] > max)
		max = in[2];

	if (max == 0) {
		out[0] = out[1] = out[2] = 1.0;
		return 0;
	}

	scale = 1.0 / max;

	VectorScale (in, scale, out);

	return max;
}



void VectorInverse (vec3_t v)
{
	v[0] = -v[0];
	v[1] = -v[1];
	v[2] = -v[2];
}

void ClearBounds (vec3_t mins, vec3_t maxs)
{
	mins[0] = mins[1] = mins[2] = 99999;
	maxs[0] = maxs[1] = maxs[2] = -99999;
}

void AddPointToBounds( const vec3_t v, vec3_t mins, vec3_t maxs ) {
	int		i;
	vec_t	val;

	for (i=0 ; i<3 ; i++)
	{
		val = v[i];
		if (val < mins[i])
			mins[i] = val;
		if (val > maxs[i])
			maxs[i] = val;
	}
}


/*
=================
PlaneTypeForNormal
=================
*/
int	PlaneTypeForNormal (vec3_t normal) {
	if (normal[0] == 1.0 || normal[0] == -1.0)
		return PLANE_X;
	if (normal[1] == 1.0 || normal[1] == -1.0)
		return PLANE_Y;
	if (normal[2] == 1.0 || normal[2] == -1.0)
		return PLANE_Z;
	
	return PLANE_NON_AXIAL;
}

/*
================
MatrixMultiply
================
*/
void MatrixMultiply(float in1[3][3], float in2[3][3], float out[3][3]) {
	out[0][0] = in1[0][0] * in2[0][0] + in1[0][1] * in2[1][0] +
				in1[0][2] * in2[2][0];
	out[0][1] = in1[0][0] * in2[0][1] + in1[0][1] * in2[1][1] +
				in1[0][2] * in2[2][1];
	out[0][2] = in1[0][0] * in2[0][2] + in1[0][1] * in2[1][2] +
				in1[0][2] * in2[2][2];
	out[1][0] = in1[1][0] * in2[0][0] + in1[1][1] * in2[1][0] +
				in1[1][2] * in2[2][0];
	out[1][1] = in1[1][0] * in2[0][1] + in1[1][1] * in2[1][1] +
				in1[1][2] * in2[2][1];
	out[1][2] = in1[1][0] * in2[0][2] + in1[1][1] * in2[1][2] +
				in1[1][2] * in2[2][2];
	out[2][0] = in1[2][0] * in2[0][0] + in1[2][1] * in2[1][0] +
				in1[2][2] * in2[2][0];
	out[2][1] = in1[2][0] * in2[0][1] + in1[2][1] * in2[1][1] +
				in1[2][2] * in2[2][1];
	out[2][2] = in1[2][0] * in2[0][2] + in1[2][1] * in2[1][2] +
				in1[2][2] * in2[2][2];
}

void ProjectPointOnPlane( vec3_t dst, const vec3_t p, const vec3_t normal )
{
	float d;
	vec3_t n;
	float inv_denom;

	inv_denom = 1.0F / DotProduct( normal, normal );

	d = DotProduct( normal, p ) * inv_denom;

	n[0] = normal[0] * inv_denom;
	n[1] = normal[1] * inv_denom;
	n[2] = normal[2] * inv_denom;

	dst[0] = p[0] - d * n[0];
	dst[1] = p[1] - d * n[1];
	dst[2] = p[2] - d * n[2];
}

/*
** assumes "src" is normalized
*/
void PerpendicularVector( vec3_t dst, const vec3_t src )
{
	int	pos;
	int i;
	float minelem = 1.0F;
	vec3_t tempvec;

	/*
	** find the smallest magnitude axially aligned vector
	*/
	for ( pos = 0, i = 0; i < 3; i++ )
	{
		if ( fabs( src[i] ) < minelem )
		{
			pos = i;
			minelem = fabs( src[i] );
		}
	}
	tempvec[0] = tempvec[1] = tempvec[2] = 0.0F;
	tempvec[pos] = 1.0F;

	/*
	** project the point onto the plane defined by src
	*/
	ProjectPointOnPlane( dst, tempvec, src );

	/*
	** normalize the result
	*/
	VectorNormalize( dst, dst );
}

/*
===============
RotatePointAroundVector

This is not implemented very well...
===============
*/
void RotatePointAroundVector( vec3_t dst, const vec3_t dir, const vec3_t point,
							 float degrees ) {
	float	m[3][3];
	float	im[3][3];
	float	zrot[3][3];
	float	tmpmat[3][3];
	float	rot[3][3];
	int	i;
	vec3_t vr, vup, vf;
	float	rad;

	vf[0] = dir[0];
	vf[1] = dir[1];
	vf[2] = dir[2];

	PerpendicularVector( vr, dir );
	CrossProduct( vr, vf, vup );

	m[0][0] = vr[0];
	m[1][0] = vr[1];
	m[2][0] = vr[2];

	m[0][1] = vup[0];
	m[1][1] = vup[1];
	m[2][1] = vup[2];

	m[0][2] = vf[0];
	m[1][2] = vf[1];
	m[2][2] = vf[2];

	memcpy( im, m, sizeof( im ) );

	im[0][1] = m[1][0];
	im[0][2] = m[2][0];
	im[1][0] = m[0][1];
	im[1][2] = m[2][1];
	im[2][0] = m[0][2];
	im[2][1] = m[1][2];

	memset( zrot, 0, sizeof( zrot ) );
	zrot[0][0] = zrot[1][1] = zrot[2][2] = 1.0F;

	rad = DEG2RAD( degrees );
	zrot[0][0] = cos( rad );
	zrot[0][1] = sin( rad );
	zrot[1][0] = -sin( rad );
	zrot[1][1] = cos( rad );

	MatrixMultiply( m, zrot, tmpmat );
	MatrixMultiply( tmpmat, im, rot );

	for ( i = 0; i < 3; i++ ) {
		dst[i] = rot[i][0] * point[0] + rot[i][1] * point[1] + rot[i][2] * point[2];
	}
}