g_math.c

来自「著名物理引擎Hawk的源代码」· C语言 代码 · 共 151 行

/* G_math.c, HAWK game engine
 *
 * Copyright 1997-1998 by Phil Frisbie, Jr.
 * for Hawk Software
 *
 */

#include "G_math.h"

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

	return length;
}

BOOL VectorCompare (vec3_t v1, vec3_t v2)
{
	int		i;
	
	for (i=0 ; i<3 ; i++)
		if (fabs(v1[i]-v2[i]) > EQUAL_EPSILON)
			return FALSE;
			
	return TRUE;
}

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

void VectorMA (vec3_t va, double scale, 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];
}

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 (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;
	_VectorScale (in, ilength, out);
	return length;
}

vec_t ColorNormalize (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)
		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 (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;
	}
}