libs/mathlib/mathlib.c

/*
Copyright (C) 1999-2006 Id Software, Inc. and contributors.
For a list of contributors, see the accompanying CONTRIBUTORS file.

This file is part of GtkRadiant.

GtkRadiant 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.

GtkRadiant 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 GtkRadiant; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

// mathlib.c -- math primitives
#include "mathlib.h"
// we use memcpy and memset
#include <memory.h>

const vec3_t vec3_origin = {0.0f,0.0f,0.0f};

const vec3_t g_vec3_axis_x = { 1, 0, 0, };
const vec3_t g_vec3_axis_y = { 0, 1, 0, };
const vec3_t g_vec3_axis_z = { 0, 0, 1, };

/*
================
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);
}

vec_t VectorLength(const vec3_t v)
{
	int		i;
	float	length;

	length = 0.0f;
	for (i=0 ; i< 3 ; i++)
		length += v[i]*v[i];
	length = (float)sqrt (length);

	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;
}

void VectorMA( const vec3_t va, vec_t 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 (vec3_t v1, 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];
}

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

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

	ilength = 1.0f/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 = 1.0f / 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 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;
}
*/

void VectorRotate (vec3_t vIn, vec3_t vRotation, vec3_t out)
{
  vec3_t vWork, va;
  int nIndex[3][2];
  int i;

  VectorCopy(vIn, va);
  VectorCopy(va, vWork);
  nIndex[0][0] = 1; nIndex[0][1] = 2;
  nIndex[1][0] = 2; nIndex[1][1] = 0;
  nIndex[2][0] = 0; nIndex[2][1] = 1;

  for (i = 0; i < 3; i++)
  {
    if (vRotation[i] != 0)
    {
      float dAngle = vRotation[i] * Q_PI / 180.0f;
	    float c = (vec_t)cos(dAngle);
      float s = (vec_t)sin(dAngle);
      vWork[nIndex[i][0]] = va[nIndex[i][0]] * c - va[nIndex[i][1]] * s;
      vWork[nIndex[i][1]] = va[nIndex[i][0]] * s + va[nIndex[i][1]] * c;
    }
    VectorCopy(vWork, va);
  }
  VectorCopy(vWork, out);
}

void VectorRotateOrigin (vec3_t vIn, vec3_t vRotation, vec3_t vOrigin, vec3_t out)
{
  vec3_t vTemp, vTemp2;

  VectorSubtract(vIn, vOrigin, vTemp);
  VectorRotate(vTemp, vRotation, vTemp2);
  VectorAdd(vTemp2, vOrigin, out);
}

void VectorPolar(vec3_t v, float radius, float theta, float phi)
{
 	v[0]=(float)(radius * cos(theta) * cos(phi));
	v[1]=(float)(radius * sin(theta) * cos(phi));
	v[2]=(float)(radius * sin(phi));
}

void VectorSnap(vec3_t v)
{
  int i;
  for (i = 0; i < 3; i++)
  {
    v[i] = (vec_t)FLOAT_TO_INTEGER(v[i]);
  }
}

void VectorISnap(vec3_t point, int snap)
{
  int i;
	for (i = 0 ;i < 3 ; i++)
	{
		point[i] = (vec_t)FLOAT_SNAP(point[i], snap);
	}
}

void VectorFSnap(vec3_t point, float snap)
{
  int i;
	for (i = 0 ;i < 3 ; i++)
	{
		point[i] = (vec_t)FLOAT_SNAP(point[i], snap);
	}
}

void _Vector5Add (vec5_t va, vec5_t vb, vec5_t out)
{
	out[0] = va[0]+vb[0];
	out[1] = va[1]+vb[1];
	out[2] = va[2]+vb[2];
	out[3] = va[3]+vb[3];
	out[4] = va[4]+vb[4];
}

void _Vector5Scale (vec5_t v, vec_t scale, vec5_t out)
{
	out[0] = v[0] * scale;
	out[1] = v[1] * scale;
	out[2] = v[2] * scale;
	out[3] = v[3] * scale;
	out[4] = v[4] * scale;
}

void _Vector53Copy (vec5_t in, vec3_t out)
{
	out[0] = in[0];
	out[1] = in[1];
	out[2] = in[2];
}

// NOTE: added these from Ritual's Q3Radiant
void ClearBounds (vec3_t mins, vec3_t maxs)
{
	mins[0] = mins[1] = mins[2] = 99999;
	maxs[0] = maxs[1] = maxs[2] = -99999;
}

void AddPointToBounds (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;
	}
}

void AngleVectors (vec3_t angles, vec3_t forward, vec3_t right, vec3_t up)
{
	float		angle;
	static float		sr, sp, sy, cr, cp, cy;
	// static to help MS compiler fp bugs

	angle = angles[YAW] * (Q_PI*2.0f / 360.0f);
	sy = (vec_t)sin(angle);
	cy = (vec_t)cos(angle);
	angle = angles[PITCH] * (Q_PI*2.0f / 360.0f);
	sp = (vec_t)sin(angle);
	cp = (vec_t)cos(angle);
	angle = angles[ROLL] * (Q_PI*2.0f / 360.0f);
	sr = (vec_t)sin(angle);
	cr = (vec_t)cos(angle);

	if (forward)
	{
		forward[0] = cp*cy;
		forward[1] = cp*sy;
		forward[2] = -sp;
	}
	if (right)
	{
		right[0] = -sr*sp*cy+cr*sy;
		right[1] = -sr*sp*sy-cr*cy;
		right[2] = -sr*cp;
	}
	if (up)
	{
		up[0] = cr*sp*cy+sr*sy;
		up[1] = cr*sp*sy-sr*cy;
		up[2] = cr*cp;
	}
}

void VectorToAngles( vec3_t vec, vec3_t angles )
{
	float forward;
	float yaw, pitch;

	if ( ( vec[ 0 ] == 0 ) && ( vec[ 1 ] == 0 ) )
	{
		yaw = 0;
		if ( vec[ 2 ] > 0 )
		{
			pitch = 90;
		}
		else
		{
			pitch = 270;
		}
	}
	else
	{
		yaw = (vec_t)atan2( vec[ 1 ], vec[ 0 ] ) * 180 / Q_PI;
		if ( yaw < 0 )
		{
			yaw += 360;
		}

		forward = ( float )sqrt( vec[ 0 ] * vec[ 0 ] + vec[ 1 ] * vec[ 1 ] );
		pitch = (vec_t)atan2( vec[ 2 ], forward ) * 180 / Q_PI;
		if ( pitch < 0 )
		{
			pitch += 360;
		}
	}

	angles[ 0 ] = pitch;
	angles[ 1 ] = yaw;
	angles[ 2 ] = 0;
}

/*
=====================
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;
}

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

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

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

/*
=================
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;
	vec_t 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 = (vec_t)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 = (float)DEG2RAD( degrees );
	zrot[0][0] = (vec_t)cos( rad );
	zrot[0][1] = (vec_t)sin( rad );
	zrot[1][0] = (vec_t)-sin( rad );
	zrot[1][1] = (vec_t)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];
	}
}