codemp/game/q_math.c

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// Copyright (C) 1999-2000 Id Software, Inc.
//
// q_math.c -- stateless support routines that are included in each code module
#include "q_shared.h"


vec3_t  vec3_origin = {0,0,0};
vec3_t  axisDefault[3] = { { 1, 0, 0 }, { 0, 1, 0 }, { 0, 0, 1 } };


vec4_t          colorBlack      = {0, 0, 0, 1};
vec4_t          colorRed        = {1, 0, 0, 1};
vec4_t          colorGreen      = {0, 1, 0, 1};
vec4_t          colorBlue       = {0, 0, 1, 1};
vec4_t          colorYellow     = {1, 1, 0, 1};
vec4_t          colorMagenta= {1, 0, 1, 1};
vec4_t          colorCyan       = {0, 1, 1, 1};
vec4_t          colorWhite      = {1, 1, 1, 1};
vec4_t          colorLtGrey     = {0.75, 0.75, 0.75, 1};
vec4_t          colorMdGrey     = {0.5, 0.5, 0.5, 1};
vec4_t          colorDkGrey     = {0.25, 0.25, 0.25, 1};

vec4_t          colorLtBlue     = {0.367f, 0.261f, 0.722f, 1};
vec4_t          colorDkBlue     = {0.199f, 0.0f,   0.398f, 1};

vec4_t  g_color_table[8] =
        {
        {0.0, 0.0, 0.0, 1.0},
        {1.0, 0.0, 0.0, 1.0},
        {0.0, 1.0, 0.0, 1.0},
        {1.0, 1.0, 0.0, 1.0},
        {0.0, 0.0, 1.0, 1.0},
        {0.0, 1.0, 1.0, 1.0},
        {1.0, 0.0, 1.0, 1.0},
        {1.0, 1.0, 1.0, 1.0},
        };


vec3_t  bytedirs[NUMVERTEXNORMALS] =
{
{-0.525731f, 0.000000f, 0.850651f}, {-0.442863f, 0.238856f, 0.864188f}, 
{-0.295242f, 0.000000f, 0.955423f}, {-0.309017f, 0.500000f, 0.809017f}, 
{-0.162460f, 0.262866f, 0.951056f}, {0.000000f, 0.000000f, 1.000000f}, 
{0.000000f, 0.850651f, 0.525731f}, {-0.147621f, 0.716567f, 0.681718f}, 
{0.147621f, 0.716567f, 0.681718f}, {0.000000f, 0.525731f, 0.850651f}, 
{0.309017f, 0.500000f, 0.809017f}, {0.525731f, 0.000000f, 0.850651f}, 
{0.295242f, 0.000000f, 0.955423f}, {0.442863f, 0.238856f, 0.864188f}, 
{0.162460f, 0.262866f, 0.951056f}, {-0.681718f, 0.147621f, 0.716567f}, 
{-0.809017f, 0.309017f, 0.500000f},{-0.587785f, 0.425325f, 0.688191f}, 
{-0.850651f, 0.525731f, 0.000000f},{-0.864188f, 0.442863f, 0.238856f}, 
{-0.716567f, 0.681718f, 0.147621f},{-0.688191f, 0.587785f, 0.425325f}, 
{-0.500000f, 0.809017f, 0.309017f}, {-0.238856f, 0.864188f, 0.442863f}, 
{-0.425325f, 0.688191f, 0.587785f}, {-0.716567f, 0.681718f, -0.147621f}, 
{-0.500000f, 0.809017f, -0.309017f}, {-0.525731f, 0.850651f, 0.000000f}, 
{0.000000f, 0.850651f, -0.525731f}, {-0.238856f, 0.864188f, -0.442863f}, 
{0.000000f, 0.955423f, -0.295242f}, {-0.262866f, 0.951056f, -0.162460f}, 
{0.000000f, 1.000000f, 0.000000f}, {0.000000f, 0.955423f, 0.295242f}, 
{-0.262866f, 0.951056f, 0.162460f}, {0.238856f, 0.864188f, 0.442863f}, 
{0.262866f, 0.951056f, 0.162460f}, {0.500000f, 0.809017f, 0.309017f}, 
{0.238856f, 0.864188f, -0.442863f},{0.262866f, 0.951056f, -0.162460f}, 
{0.500000f, 0.809017f, -0.309017f},{0.850651f, 0.525731f, 0.000000f}, 
{0.716567f, 0.681718f, 0.147621f}, {0.716567f, 0.681718f, -0.147621f}, 
{0.525731f, 0.850651f, 0.000000f}, {0.425325f, 0.688191f, 0.587785f}, 
{0.864188f, 0.442863f, 0.238856f}, {0.688191f, 0.587785f, 0.425325f}, 
{0.809017f, 0.309017f, 0.500000f}, {0.681718f, 0.147621f, 0.716567f}, 
{0.587785f, 0.425325f, 0.688191f}, {0.955423f, 0.295242f, 0.000000f}, 
{1.000000f, 0.000000f, 0.000000f}, {0.951056f, 0.162460f, 0.262866f}, 
{0.850651f, -0.525731f, 0.000000f},{0.955423f, -0.295242f, 0.000000f}, 
{0.864188f, -0.442863f, 0.238856f}, {0.951056f, -0.162460f, 0.262866f}, 
{0.809017f, -0.309017f, 0.500000f}, {0.681718f, -0.147621f, 0.716567f}, 
{0.850651f, 0.000000f, 0.525731f}, {0.864188f, 0.442863f, -0.238856f}, 
{0.809017f, 0.309017f, -0.500000f}, {0.951056f, 0.162460f, -0.262866f}, 
{0.525731f, 0.000000f, -0.850651f}, {0.681718f, 0.147621f, -0.716567f}, 
{0.681718f, -0.147621f, -0.716567f},{0.850651f, 0.000000f, -0.525731f}, 
{0.809017f, -0.309017f, -0.500000f}, {0.864188f, -0.442863f, -0.238856f}, 
{0.951056f, -0.162460f, -0.262866f}, {0.147621f, 0.716567f, -0.681718f}, 
{0.309017f, 0.500000f, -0.809017f}, {0.425325f, 0.688191f, -0.587785f}, 
{0.442863f, 0.238856f, -0.864188f}, {0.587785f, 0.425325f, -0.688191f}, 
{0.688191f, 0.587785f, -0.425325f}, {-0.147621f, 0.716567f, -0.681718f}, 
{-0.309017f, 0.500000f, -0.809017f}, {0.000000f, 0.525731f, -0.850651f}, 
{-0.525731f, 0.000000f, -0.850651f}, {-0.442863f, 0.238856f, -0.864188f}, 
{-0.295242f, 0.000000f, -0.955423f}, {-0.162460f, 0.262866f, -0.951056f}, 
{0.000000f, 0.000000f, -1.000000f}, {0.295242f, 0.000000f, -0.955423f}, 
{0.162460f, 0.262866f, -0.951056f}, {-0.442863f, -0.238856f, -0.864188f}, 
{-0.309017f, -0.500000f, -0.809017f}, {-0.162460f, -0.262866f, -0.951056f}, 
{0.000000f, -0.850651f, -0.525731f}, {-0.147621f, -0.716567f, -0.681718f}, 
{0.147621f, -0.716567f, -0.681718f}, {0.000000f, -0.525731f, -0.850651f}, 
{0.309017f, -0.500000f, -0.809017f}, {0.442863f, -0.238856f, -0.864188f}, 
{0.162460f, -0.262866f, -0.951056f}, {0.238856f, -0.864188f, -0.442863f}, 
{0.500000f, -0.809017f, -0.309017f}, {0.425325f, -0.688191f, -0.587785f}, 
{0.716567f, -0.681718f, -0.147621f}, {0.688191f, -0.587785f, -0.425325f}, 
{0.587785f, -0.425325f, -0.688191f}, {0.000000f, -0.955423f, -0.295242f}, 
{0.000000f, -1.000000f, 0.000000f}, {0.262866f, -0.951056f, -0.162460f}, 
{0.000000f, -0.850651f, 0.525731f}, {0.000000f, -0.955423f, 0.295242f}, 
{0.238856f, -0.864188f, 0.442863f}, {0.262866f, -0.951056f, 0.162460f}, 
{0.500000f, -0.809017f, 0.309017f}, {0.716567f, -0.681718f, 0.147621f}, 
{0.525731f, -0.850651f, 0.000000f}, {-0.238856f, -0.864188f, -0.442863f}, 
{-0.500000f, -0.809017f, -0.309017f}, {-0.262866f, -0.951056f, -0.162460f}, 
{-0.850651f, -0.525731f, 0.000000f}, {-0.716567f, -0.681718f, -0.147621f}, 
{-0.716567f, -0.681718f, 0.147621f}, {-0.525731f, -0.850651f, 0.000000f}, 
{-0.500000f, -0.809017f, 0.309017f}, {-0.238856f, -0.864188f, 0.442863f}, 
{-0.262866f, -0.951056f, 0.162460f}, {-0.864188f, -0.442863f, 0.238856f}, 
{-0.809017f, -0.309017f, 0.500000f}, {-0.688191f, -0.587785f, 0.425325f}, 
{-0.681718f, -0.147621f, 0.716567f}, {-0.442863f, -0.238856f, 0.864188f}, 
{-0.587785f, -0.425325f, 0.688191f}, {-0.309017f, -0.500000f, 0.809017f}, 
{-0.147621f, -0.716567f, 0.681718f}, {-0.425325f, -0.688191f, 0.587785f}, 
{-0.162460f, -0.262866f, 0.951056f}, {0.442863f, -0.238856f, 0.864188f}, 
{0.162460f, -0.262866f, 0.951056f}, {0.309017f, -0.500000f, 0.809017f}, 
{0.147621f, -0.716567f, 0.681718f}, {0.000000f, -0.525731f, 0.850651f}, 
{0.425325f, -0.688191f, 0.587785f}, {0.587785f, -0.425325f, 0.688191f}, 
{0.688191f, -0.587785f, 0.425325f}, {-0.955423f, 0.295242f, 0.000000f}, 
{-0.951056f, 0.162460f, 0.262866f}, {-1.000000f, 0.000000f, 0.000000f}, 
{-0.850651f, 0.000000f, 0.525731f}, {-0.955423f, -0.295242f, 0.000000f}, 
{-0.951056f, -0.162460f, 0.262866f}, {-0.864188f, 0.442863f, -0.238856f}, 
{-0.951056f, 0.162460f, -0.262866f}, {-0.809017f, 0.309017f, -0.500000f}, 
{-0.864188f, -0.442863f, -0.238856f}, {-0.951056f, -0.162460f, -0.262866f}, 
{-0.809017f, -0.309017f, -0.500000f}, {-0.681718f, 0.147621f, -0.716567f}, 
{-0.681718f, -0.147621f, -0.716567f}, {-0.850651f, 0.000000f, -0.525731f}, 
{-0.688191f, 0.587785f, -0.425325f}, {-0.587785f, 0.425325f, -0.688191f}, 
{-0.425325f, 0.688191f, -0.587785f}, {-0.425325f, -0.688191f, -0.587785f}, 
{-0.587785f, -0.425325f, -0.688191f}, {-0.688191f, -0.587785f, -0.425325f}
};

//==============================================================

int             Q_rand( int *seed ) {
        *seed = (69069 * *seed + 1);
        return *seed;
}

float   Q_random( int *seed ) {
        return ( Q_rand( seed ) & 0xffff ) / (float)0x10000;
}

float   Q_crandom( int *seed ) {
        return 2.0 * ( Q_random( seed ) - 0.5 );
}

#ifdef __LCC__

int VectorCompare( const vec3_t v1, const vec3_t v2 ) {
        if (v1[0] != v2[0] || v1[1] != v2[1] || v1[2] != v2[2]) {
                return 0;
        }                       
        return 1;
}

vec_t VectorLength( const vec3_t v ) {
        return (vec_t)sqrt (v[0]*v[0] + v[1]*v[1] + v[2]*v[2]);
}

vec_t VectorLengthSquared( const vec3_t v ) {
        return (v[0]*v[0] + v[1]*v[1] + v[2]*v[2]);
}

vec_t Distance( const vec3_t p1, const vec3_t p2 ) {
        vec3_t  v;

        VectorSubtract (p2, p1, v);
        return VectorLength( v );
}

vec_t DistanceSquared( const vec3_t p1, const vec3_t p2 ) {
        vec3_t  v;

        VectorSubtract (p2, p1, v);
        return v[0]*v[0] + v[1]*v[1] + v[2]*v[2];
}

// fast vector normalize routine that does not check to make sure
// that length != 0, nor does it return length, uses rsqrt approximation
void VectorNormalizeFast( vec3_t v )
{
        float ilength;

        ilength = Q_rsqrt( DotProduct( v, v ) );

        v[0] *= ilength;
        v[1] *= ilength;
        v[2] *= ilength;
}

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

//i wrote this function in a console test app and it appeared faster
//in debug and release than the standard crossproduct asm generated
//by the compiler. however, when inlining the crossproduct function
//the compiler performs further optimizations and generally ends up
//being faster than this asm version. but feel free to try this one
//and see if you're heavily crossproducting in an area and looking
//for a way to optimize. -rww
#if 0
void CrossProductA (float *v1, float *v2, float *cross)
{
#if 1
        static float scratch1, scratch2, scratch3, scratch4, scratch5, scratch6;

        __asm mov   eax,v1
        __asm mov   ecx,v2
        __asm mov   edx,cross

        __asm fld   dword ptr[eax+4]
        __asm fmul  dword ptr[ecx+8]
        __asm fstp  scratch1

        __asm fld   dword ptr[eax+8]
        __asm fmul  dword ptr[ecx+4]
        __asm fstp  scratch2

        __asm fld   dword ptr[eax+8]
        __asm fmul  dword ptr[ecx]
        __asm fstp  scratch3

        __asm fld   dword ptr[eax]
        __asm fmul  dword ptr[ecx+8]
        __asm fstp  scratch4

        __asm fld   dword ptr[eax]
        __asm fmul  dword ptr[ecx+4]
        __asm fstp  scratch5

        __asm fld   dword ptr[eax+4]
        __asm fmul  dword ptr[ecx]
        __asm fstp  scratch6

        __asm fld   scratch1
        __asm fsub  scratch2
        __asm fstp  dword ptr[edx]

        __asm fld   scratch3
        __asm fsub  scratch4
        __asm fstp  dword ptr[edx+4]

        __asm fld   scratch5
        __asm fsub  scratch6
        __asm fstp  dword ptr[edx+8]
#else //doesn't require use of statics, but not nearly as fast.
        __asm mov   eax,v1
        __asm mov   ecx,v2
        __asm mov   edx,cross

        __asm fld   dword ptr[eax+4]
        __asm fmul  dword ptr[ecx+8]
        __asm fld   dword ptr[eax+8]
        __asm fmul  dword ptr[ecx+4]
        __asm fsubp st(1),st
        __asm fstp  dword ptr[edx]

        __asm fld   dword ptr[eax+8]
        __asm fmul  dword ptr[ecx]
        __asm fld   dword ptr[eax]
        __asm fmul  dword ptr[ecx+8]
        __asm fsubp st(1),st
        __asm fstp  dword ptr[edx+4]

        __asm fld   dword ptr[eax]
        __asm fmul  dword ptr[ecx+4]
        __asm fld   dword ptr[eax+4]
        __asm fmul  dword ptr[ecx]
        __asm fsubp st(1),st
        __asm fstp  dword ptr[edx+8]
#endif
}
#endif

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];
}
#endif

//=======================================================

signed char ClampChar( int i ) {
        if ( i < -128 ) {
                return -128;
        }
        if ( i > 127 ) {
                return 127;
        }
        return i;
}

signed short ClampShort( int i ) {
        if ( i < -32768 ) {
                return -32768;
        }
        if ( i > 0x7fff ) {
                return 0x7fff;
        }
        return i;
}


// this isn't a real cheap function to call!
int DirToByte( vec3_t dir ) {
        int             i, best;
        float   d, bestd;

        if ( !dir ) {
                return 0;
        }

        bestd = 0;
        best = 0;
        for (i=0 ; i<NUMVERTEXNORMALS ; i++)
        {
                d = DotProduct (dir, bytedirs[i]);
                if (d > bestd)
                {
                        bestd = d;
                        best = i;
                }
        }

        return best;
}

void ByteToDir( int b, vec3_t dir ) {
        if ( b < 0 || b >= NUMVERTEXNORMALS ) {
                VectorCopy( vec3_origin, dir );
                return;
        }
        VectorCopy (bytedirs[b], dir);
}


unsigned ColorBytes3 (float r, float g, float b) {
        unsigned        i;

        ( (byte *)&i )[0] = r * 255;
        ( (byte *)&i )[1] = g * 255;
        ( (byte *)&i )[2] = b * 255;

        return i;
}

unsigned ColorBytes4 (float r, float g, float b, float a) {
        unsigned        i;

        ( (byte *)&i )[0] = r * 255;
        ( (byte *)&i )[1] = g * 255;
        ( (byte *)&i )[2] = b * 255;
        ( (byte *)&i )[3] = a * 255;

        return i;
}

float NormalizeColor( const vec3_t in, vec3_t out ) {
        float   max;
        
        max = in[0];
        if ( in[1] > max ) {
                max = in[1];
        }
        if ( in[2] > max ) {
                max = in[2];
        }

        if ( !max ) {
                VectorClear( out );
        } else {
                out[0] = in[0] / max;
                out[1] = in[1] / max;
                out[2] = in[2] / max;
        }
        return max;
}


/*
=====================
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 ) == 0 ) {
                return qfalse;
        }

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

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

/*
===============
RotateAroundDirection
===============
*/
void RotateAroundDirection( vec3_t axis[3], float yaw ) {

        // create an arbitrary axis[1] 
        PerpendicularVector( axis[1], axis[0] );

        // rotate it around axis[0] by yaw
        if ( yaw ) {
                vec3_t  temp;

                VectorCopy( axis[1], temp );
                RotatePointAroundVector( axis[1], axis[0], temp, yaw );
        }

        // cross to get axis[2]
        CrossProduct( axis[0], axis[1], axis[2] );
}



void vectoangles( const vec3_t value1, vec3_t angles ) {
        float   forward;
        float   yaw, pitch;
        
        if ( value1[1] == 0 && value1[0] == 0 ) {
                yaw = 0;
                if ( value1[2] > 0 ) {
                        pitch = 90;
                }
                else {
                        pitch = 270;
                }
        }
        else {
                if ( value1[0] ) {
                        yaw = ( atan2 ( value1[1], value1[0] ) * 180 / M_PI );
                }
                else if ( value1[1] > 0 ) {
                        yaw = 90;
                }
                else {
                        yaw = 270;
                }
                if ( yaw < 0 ) {
                        yaw += 360;
                }

                forward = sqrt ( value1[0]*value1[0] + value1[1]*value1[1] );
                pitch = ( atan2(value1[2], forward) * 180 / M_PI );
                if ( pitch < 0 ) {
                        pitch += 360;
                }
        }

        angles[PITCH] = -pitch;
        angles[YAW] = yaw;
        angles[ROLL] = 0;
}


/*
=================
AnglesToAxis
=================
*/
void AnglesToAxis( const vec3_t angles, vec3_t axis[3] ) {
        vec3_t  right;

        // angle vectors returns "right" instead of "y axis"
        AngleVectors( angles, axis[0], right, axis[2] );
        VectorSubtract( vec3_origin, right, axis[1] );
}

void AxisClear( vec3_t axis[3] ) {
        axis[0][0] = 1;
        axis[0][1] = 0;
        axis[0][2] = 0;
        axis[1][0] = 0;
        axis[1][1] = 1;
        axis[1][2] = 0;
        axis[2][0] = 0;
        axis[2][1] = 0;
        axis[2][2] = 1;
}

void AxisCopy( vec3_t in[3], vec3_t out[3] ) {
        VectorCopy( in[0], out[0] );
        VectorCopy( in[1], out[1] );
        VectorCopy( in[2], out[2] );
}

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

        inv_denom =  DotProduct( normal, normal );
#ifndef Q3_VM
        assert( Q_fabs(inv_denom) != 0.0f ); // bk010122 - zero vectors get here
#endif
        inv_denom = 1.0f / inv_denom;

        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];
}

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

Given a normalized forward vector, create two
other perpendicular vectors
================
*/
void MakeNormalVectors( const 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);
        CrossProduct (right, forward, up);
}


void VectorRotate( vec3_t in, vec3_t matrix[3], vec3_t out )
{
        out[0] = DotProduct( in, matrix[0] );
        out[1] = DotProduct( in, matrix[1] );
        out[2] = DotProduct( in, matrix[2] );
}

//============================================================================

#if !idppc
/*
** float q_rsqrt( float number )
*/
float Q_rsqrt( float number )
{
        long i;
        float x2, y;
        const float threehalfs = 1.5F;

        x2 = number * 0.5F;
        y  = number;
        i  = * ( long * ) &y;                                           // evil floating point bit level hacking
        i  = 0x5f3759df - ( i >> 1 );               // what the fuck?
        y  = * ( float * ) &i;
        y  = y * ( threehalfs - ( x2 * y * y ) );   // 1st iteration
//      y  = y * ( threehalfs - ( x2 * y * y ) );   // 2nd iteration, this can be removed

#ifndef Q3_VM
#ifdef __linux__
        assert( !isnan(y) ); // bk010122 - FPE?
#endif
#endif
        return y;
}

float Q_fabs( float f ) {
        int tmp = * ( int * ) &f;
        tmp &= 0x7FFFFFFF;
        return * ( float * ) &tmp;
}
#endif

//============================================================

/*
===============
LerpAngle

===============
*/
float LerpAngle (float from, float to, float frac) {
        float   a;

        if ( to - from > 180 ) {
                to -= 360;
        }
        if ( to - from < -180 ) {
                to += 360;
        }
        a = from + frac * (to - from);

        return a;
}


/*
=================
AngleSubtract

Always returns a value from -180 to 180
=================
*/
float   AngleSubtract( float a1, float a2 ) {
        float   a;

        a = a1 - a2;
        a=fmod(a,360);//chop it down quickly, then level it out
        while ( a > 180 ) {
                a -= 360;
        }
        while ( a < -180 ) {
                a += 360;
        }
        return a;
}


void AnglesSubtract( vec3_t v1, vec3_t v2, vec3_t v3 ) {
        v3[0] = AngleSubtract( v1[0], v2[0] );
        v3[1] = AngleSubtract( v1[1], v2[1] );
        v3[2] = AngleSubtract( v1[2], v2[2] );
}


float   AngleMod(float a) {
        a = (360.0/65536) * ((int)(a*(65536/360.0)) & 65535);
        return a;
}


/*
=================
AngleNormalize360

returns angle normalized to the range [0 <= angle < 360]
=================
*/
float AngleNormalize360 ( float angle ) {
        return (360.0 / 65536) * ((int)(angle * (65536 / 360.0)) & 65535);
}


/*
=================
AngleNormalize180

returns angle normalized to the range [-180 < angle <= 180]
=================
*/
float AngleNormalize180 ( float angle ) {
        angle = AngleNormalize360( angle );
        if ( angle > 180.0 ) {
                angle -= 360.0;
        }
        return angle;
}


/*
=================
AngleDelta

returns the normalized delta from angle1 to angle2
=================
*/
float AngleDelta ( float angle1, float angle2 ) {
        return AngleNormalize180( angle1 - angle2 );
}


//============================================================


/*
=================
SetPlaneSignbits
=================
*/
void SetPlaneSignbits (cplane_t *out) {
        int     bits, j;

        // for fast box on planeside test
        bits = 0;
        for (j=0 ; j<3 ; j++) {
                if (out->normal[j] < 0) {
                        bits |= 1<<j;
                }
        }
        out->signbits = bits;
}


/*
==================
BoxOnPlaneSide

Returns 1, 2, or 1 + 2

// this is the slow, general version
int BoxOnPlaneSide2 (vec3_t emins, vec3_t emaxs, struct cplane_s *p)
{
        int             i;
        float   dist1, dist2;
        int             sides;
        vec3_t  corners[2];

        for (i=0 ; i<3 ; i++)
        {
                if (p->normal[i] < 0)
                {
                        corners[0][i] = emins[i];
                        corners[1][i] = emaxs[i];
                }
                else
                {
                        corners[1][i] = emins[i];
                        corners[0][i] = emaxs[i];
                }
        }
        dist1 = DotProduct (p->normal, corners[0]) - p->dist;
        dist2 = DotProduct (p->normal, corners[1]) - p->dist;
        sides = 0;
        if (dist1 >= 0)
                sides = 1;
        if (dist2 < 0)
                sides |= 2;

        return sides;
}

==================
*/
#if !( (defined __linux__ || __FreeBSD__) && (defined __i386__) && (!defined C_ONLY)) // rb010123

#if defined __LCC__ || defined C_ONLY || !id386

int BoxOnPlaneSide (vec3_t emins, vec3_t emaxs, struct cplane_s *p)
{
        float   dist1, dist2;
        int             sides;

// fast axial cases
        if (p->type < 3)
        {
                if (p->dist <= emins[p->type])
                        return 1;
                if (p->dist >= emaxs[p->type])
                        return 2;
                return 3;
        }

// general case
        switch (p->signbits)
        {
        case 0:
                dist1 = p->normal[0]*emaxs[0] + p->normal[1]*emaxs[1] + p->normal[2]*emaxs[2];
                dist2 = p->normal[0]*emins[0] + p->normal[1]*emins[1] + p->normal[2]*emins[2];
                break;
        case 1:
                dist1 = p->normal[0]*emins[0] + p->normal[1]*emaxs[1] + p->normal[2]*emaxs[2];
                dist2 = p->normal[0]*emaxs[0] + p->normal[1]*emins[1] + p->normal[2]*emins[2];
                break;
        case 2:
                dist1 = p->normal[0]*emaxs[0] + p->normal[1]*emins[1] + p->normal[2]*emaxs[2];
                dist2 = p->normal[0]*emins[0] + p->normal[1]*emaxs[1] + p->normal[2]*emins[2];
                break;
        case 3:
                dist1 = p->normal[0]*emins[0] + p->normal[1]*emins[1] + p->normal[2]*emaxs[2];
                dist2 = p->normal[0]*emaxs[0] + p->normal[1]*emaxs[1] + p->normal[2]*emins[2];
                break;
        case 4:
                dist1 = p->normal[0]*emaxs[0] + p->normal[1]*emaxs[1] + p->normal[2]*emins[2];
                dist2 = p->normal[0]*emins[0] + p->normal[1]*emins[1] + p->normal[2]*emaxs[2];
                break;
        case 5:
                dist1 = p->normal[0]*emins[0] + p->normal[1]*emaxs[1] + p->normal[2]*emins[2];
                dist2 = p->normal[0]*emaxs[0] + p->normal[1]*emins[1] + p->normal[2]*emaxs[2];
                break;
        case 6:
                dist1 = p->normal[0]*emaxs[0] + p->normal[1]*emins[1] + p->normal[2]*emins[2];
                dist2 = p->normal[0]*emins[0] + p->normal[1]*emaxs[1] + p->normal[2]*emaxs[2];
                break;
        case 7:
                dist1 = p->normal[0]*emins[0] + p->normal[1]*emins[1] + p->normal[2]*emins[2];
                dist2 = p->normal[0]*emaxs[0] + p->normal[1]*emaxs[1] + p->normal[2]*emaxs[2];
                break;
        default:
                dist1 = dist2 = 0;              // shut up compiler
                break;
        }

        sides = 0;
        if (dist1 >= p->dist)
                sides = 1;
        if (dist2 < p->dist)
                sides |= 2;

        return sides;
}
#else
#pragma warning( disable: 4035 )

__declspec( naked ) int BoxOnPlaneSide (vec3_t emins, vec3_t emaxs, struct cplane_s *p)
{
        static int bops_initialized;
        static int Ljmptab[8];

        __asm {

                push ebx
                        
                cmp bops_initialized, 1
                je  initialized
                mov bops_initialized, 1
                
                mov Ljmptab[0*4], offset Lcase0
                mov Ljmptab[1*4], offset Lcase1
                mov Ljmptab[2*4], offset Lcase2
                mov Ljmptab[3*4], offset Lcase3
                mov Ljmptab[4*4], offset Lcase4
                mov Ljmptab[5*4], offset Lcase5
                mov Ljmptab[6*4], offset Lcase6
                mov Ljmptab[7*4], offset Lcase7
                        
initialized:

                mov edx,dword ptr[4+12+esp]
                mov ecx,dword ptr[4+4+esp]
                xor eax,eax
                mov ebx,dword ptr[4+8+esp]
                mov al,byte ptr[17+edx]
                cmp al,8
                jge Lerror
                fld dword ptr[0+edx]
                fld st(0)
                jmp dword ptr[Ljmptab+eax*4]
Lcase0:
                fmul dword ptr[ebx]
                fld dword ptr[0+4+edx]
                fxch st(2)
                fmul dword ptr[ecx]
                fxch st(2)
                fld st(0)
                fmul dword ptr[4+ebx]
                fld dword ptr[0+8+edx]
                fxch st(2)
                fmul dword ptr[4+ecx]
                fxch st(2)
                fld st(0)
                fmul dword ptr[8+ebx]
                fxch st(5)
                faddp st(3),st(0)
                fmul dword ptr[8+ecx]
                fxch st(1)
                faddp st(3),st(0)
                fxch st(3)
                faddp st(2),st(0)
                jmp LSetSides
Lcase1:
                fmul dword ptr[ecx]
                fld dword ptr[0+4+edx]
                fxch st(2)
                fmul dword ptr[ebx]
                fxch st(2)
                fld st(0)
                fmul dword ptr[4+ebx]
                fld dword ptr[0+8+edx]
                fxch st(2)
                fmul dword ptr[4+ecx]
                fxch st(2)
                fld st(0)
                fmul dword ptr[8+ebx]
                fxch st(5)
                faddp st(3),st(0)
                fmul dword ptr[8+ecx]
                fxch st(1)
                faddp st(3),st(0)
                fxch st(3)
                faddp st(2),st(0)
                jmp LSetSides
Lcase2:
                fmul dword ptr[ebx]
                fld dword ptr[0+4+edx]
                fxch st(2)
                fmul dword ptr[ecx]
                fxch st(2)
                fld st(0)
                fmul dword ptr[4+ecx]
                fld dword ptr[0+8+edx]
                fxch st(2)
                fmul dword ptr[4+ebx]
                fxch st(2)
                fld st(0)
                fmul dword ptr[8+ebx]
                fxch st(5)
                faddp st(3),st(0)
                fmul dword ptr[8+ecx]
                fxch st(1)
                faddp st(3),st(0)
                fxch st(3)
                faddp st(2),st(0)
                jmp LSetSides
Lcase3:
                fmul dword ptr[ecx]
                fld dword ptr[0+4+edx]
                fxch st(2)
                fmul dword ptr[ebx]
                fxch st(2)
                fld st(0)
                fmul dword ptr[4+ecx]
                fld dword ptr[0+8+edx]
                fxch st(2)
                fmul dword ptr[4+ebx]
                fxch st(2)
                fld st(0)
                fmul dword ptr[8+ebx]
                fxch st(5)
                faddp st(3),st(0)
                fmul dword ptr[8+ecx]
                fxch st(1)
                faddp st(3),st(0)
                fxch st(3)
                faddp st(2),st(0)
                jmp LSetSides
Lcase4:
                fmul dword ptr[ebx]
                fld dword ptr[0+4+edx]
                fxch st(2)
                fmul dword ptr[ecx]
                fxch st(2)
                fld st(0)
                fmul dword ptr[4+ebx]
                fld dword ptr[0+8+edx]
                fxch st(2)
                fmul dword ptr[4+ecx]
                fxch st(2)
                fld st(0)
                fmul dword ptr[8+ecx]
                fxch st(5)
                faddp st(3),st(0)
                fmul dword ptr[8+ebx]
                fxch st(1)
                faddp st(3),st(0)
                fxch st(3)
                faddp st(2),st(0)
                jmp LSetSides
Lcase5:
                fmul dword ptr[ecx]
                fld dword ptr[0+4+edx]
                fxch st(2)
                fmul dword ptr[ebx]
                fxch st(2)
                fld st(0)
                fmul dword ptr[4+ebx]
                fld dword ptr[0+8+edx]
                fxch st(2)
                fmul dword ptr[4+ecx]
                fxch st(2)
                fld st(0)
                fmul dword ptr[8+ecx]
                fxch st(5)
                faddp st(3),st(0)
                fmul dword ptr[8+ebx]
                fxch st(1)
                faddp st(3),st(0)
                fxch st(3)
                faddp st(2),st(0)
                jmp LSetSides
Lcase6:
                fmul dword ptr[ebx]
                fld dword ptr[0+4+edx]
                fxch st(2)
                fmul dword ptr[ecx]
                fxch st(2)
                fld st(0)
                fmul dword ptr[4+ecx]
                fld dword ptr[0+8+edx]
                fxch st(2)
                fmul dword ptr[4+ebx]
                fxch st(2)
                fld st(0)
                fmul dword ptr[8+ecx]
                fxch st(5)
                faddp st(3),st(0)
                fmul dword ptr[8+ebx]
                fxch st(1)
                faddp st(3),st(0)
                fxch st(3)
                faddp st(2),st(0)
                jmp LSetSides
Lcase7:
                fmul dword ptr[ecx]
                fld dword ptr[0+4+edx]
                fxch st(2)
                fmul dword ptr[ebx]
                fxch st(2)
                fld st(0)
                fmul dword ptr[4+ecx]
                fld dword ptr[0+8+edx]
                fxch st(2)
                fmul dword ptr[4+ebx]
                fxch st(2)
                fld st(0)
                fmul dword ptr[8+ecx]
                fxch st(5)
                faddp st(3),st(0)
                fmul dword ptr[8+ebx]
                fxch st(1)
                faddp st(3),st(0)
                fxch st(3)
                faddp st(2),st(0)
LSetSides:
                faddp st(2),st(0)
                fcomp dword ptr[12+edx]
                xor ecx,ecx
                fnstsw ax
                fcomp dword ptr[12+edx]
                and ah,1
                xor ah,1
                add cl,ah
                fnstsw ax
                and ah,1
                add ah,ah
                add cl,ah
                pop ebx
                mov eax,ecx
                ret
Lerror:
                int 3
        }
}
#pragma warning( default: 4035 )

#endif
#endif

/*
=================
RadiusFromBounds
=================
*/
float RadiusFromBounds( const vec3_t mins, const vec3_t maxs ) {
        int             i;
        vec3_t  corner;
        float   a, b;

        for (i=0 ; i<3 ; i++) {
                a = fabs( mins[i] );
                b = fabs( maxs[i] );
                corner[i] = a > b ? a : b;
        }

        return VectorLength (corner);
}


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

vec_t DistanceHorizontal( const vec3_t p1, const vec3_t p2 ) {
        vec3_t  v;

        VectorSubtract( p2, p1, v );
        return sqrt( v[0]*v[0] + v[1]*v[1] );   //Leave off the z component
}

vec_t DistanceHorizontalSquared( const vec3_t p1, const vec3_t p2 ) {
        vec3_t  v;

        VectorSubtract( p2, p1, v );
        return v[0]*v[0] + v[1]*v[1];   //Leave off the z component
}

void AddPointToBounds( const vec3_t v, vec3_t mins, vec3_t maxs ) {
        if ( v[0] < mins[0] ) {
                mins[0] = v[0];
        }
        if ( v[0] > maxs[0]) {
                maxs[0] = v[0];
        }

        if ( v[1] < mins[1] ) {
                mins[1] = v[1];
        }
        if ( v[1] > maxs[1]) {
                maxs[1] = v[1];
        }

        if ( v[2] < mins[2] ) {
                mins[2] = v[2];
        }
        if ( v[2] > maxs[2]) {
                maxs[2] = v[2];
        }
}


vec_t VectorNormalize( vec3_t v ) {
        float   length, ilength;

        length = v[0]*v[0] + v[1]*v[1] + v[2]*v[2];
        length = sqrt (length);

        if ( length ) {
                ilength = 1/length;
                v[0] *= ilength;
                v[1] *= ilength;
                v[2] *= ilength;
        }
                
        return length;
}

vec_t VectorNormalize2( const vec3_t v, vec3_t out) {
        float   length, ilength;

        length = v[0]*v[0] + v[1]*v[1] + v[2]*v[2];
        length = sqrt (length);

        if (length)
        {
#ifndef Q3_VM // bk0101022 - FPE related
//        assert( ((Q_fabs(v[0])!=0.0f) || (Q_fabs(v[1])!=0.0f) || (Q_fabs(v[2])!=0.0f)) );
#endif
                ilength = 1/length;
                out[0] = v[0]*ilength;
                out[1] = v[1]*ilength;
                out[2] = v[2]*ilength;
        } else {
#ifndef Q3_VM // bk0101022 - FPE related
//        assert( ((Q_fabs(v[0])==0.0f) && (Q_fabs(v[1])==0.0f) && (Q_fabs(v[2])==0.0f)) );
#endif
                VectorClear( out );
        }
                
        return length;

}

void _VectorMA( const vec3_t veca, float scale, const vec3_t vecb, vec3_t vecc) {
        vecc[0] = veca[0] + scale*vecb[0];
        vecc[1] = veca[1] + scale*vecb[1];
        vecc[2] = veca[2] + scale*vecb[2];
}


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

void _VectorSubtract( const vec3_t veca, const vec3_t vecb, vec3_t out ) {
        out[0] = veca[0]-vecb[0];
        out[1] = veca[1]-vecb[1];
        out[2] = veca[2]-vecb[2];
}

void _VectorAdd( const vec3_t veca, const vec3_t vecb, vec3_t out ) {
        out[0] = veca[0]+vecb[0];
        out[1] = veca[1]+vecb[1];
        out[2] = veca[2]+vecb[2];
}

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

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

void Vector4Scale( const vec4_t in, vec_t scale, vec4_t out ) {
        out[0] = in[0]*scale;
        out[1] = in[1]*scale;
        out[2] = in[2]*scale;
        out[3] = in[3]*scale;
}


int Q_log2( int val ) {
        int answer;

        answer = 0;
        while ( ( val>>=1 ) != 0 ) {
                answer++;
        }
        return answer;
}



/*
=================
PlaneTypeForNormal
=================
*/
/*
int     PlaneTypeForNormal (vec3_t normal) {
        if ( normal[0] == 1.0 )
                return PLANE_X;
        if ( normal[1] == 1.0 )
                return PLANE_Y;
        if ( 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 AngleVectors( const 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] * (M_PI*2 / 360);
        sy = sin(angle);
        cy = cos(angle);
        angle = angles[PITCH] * (M_PI*2 / 360);
        sp = sin(angle);
        cp = cos(angle);
        angle = angles[ROLL] * (M_PI*2 / 360);
        sr = sin(angle);
        cr = cos(angle);

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

/*
** 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 );
}

/*
** 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
**
*/
//rwwRMG - added
void NormalToLatLong( const vec3_t normal, byte bytes[2] )
{
        // check for singularities
        if (!normal[0] && !normal[1])
        {
                if ( normal[2] > 0.0f )
                {
                        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( (vec_t)atan2( normal[1], normal[0] ) ) * (255.0f / 360.0f ));
                a &= 0xff;

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

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

// This is the VC libc version of rand() without multiple seeds per thread or 12 levels
// of subroutine calls.
// Both calls have been designed to minimise the inherent number of float <--> int 
// conversions and the additional math required to get the desired value.
// eg the typical tint = (rand() * 255) / 32768
// becomes tint = irand(0, 255)

static unsigned long    holdrand = 0x89abcdef;

void Rand_Init(int seed)
{
        holdrand = seed;
}

// Returns a float min <= x < max (exclusive; will get max - 0.00001; but never max)

float flrand(float min, float max)
{
        float   result;

        holdrand = (holdrand * 214013L) + 2531011L;
        result = (float)(holdrand >> 17);                                               // 0 - 32767 range
        result = ((result * (max - min)) / 32768.0F) + min;

        return(result);
}
float Q_flrand(float min, float max)
{
        return flrand(min,max);
}

// Returns an integer min <= x <= max (ie inclusive)

int irand(int min, int max)
{
        int             result;

        assert((max - min) < 32768);

        max++;
        holdrand = (holdrand * 214013L) + 2531011L;
        result = holdrand >> 17;
        result = ((result * (max - min)) >> 15) + min;
        return(result);
}

int Q_irand(int value1, int value2)
{
        return irand(value1, value2);
}

float powf ( float x, int y )
{
        float r = x;
        for ( y--; y>0; y-- )
                r = r * r;
        return r;
}

#ifdef Q3_VM 
//rwwRMG - needed for HandleEntityAdjustment
double fmod( double x, double y )
{
        int             result;

        if (y == 0.0)
        {
                return 0.0;
        }

        result = x / y;

        return x - (result * y);
}

#endif // Q3_VM

/*
-------------------------
DotProductNormalize
-------------------------
*/

float DotProductNormalize( const vec3_t inVec1, const vec3_t inVec2 )
{
        vec3_t  v1, v2;

        VectorNormalize2( inVec1, v1 );
        VectorNormalize2( inVec2, v2 );

        return DotProduct(v1, v2);
}

/*
-------------------------
G_FindClosestPointOnLineSegment
-------------------------
*/

qboolean G_FindClosestPointOnLineSegment( const vec3_t start, const vec3_t end, const vec3_t from, vec3_t result )
{
        vec3_t  vecStart2From, vecStart2End, vecEnd2Start, vecEnd2From;
        float   distEnd2From, distEnd2Result, theta, cos_theta, dot;

        //Find the perpendicular vector to vec from start to end
        VectorSubtract( from, start, vecStart2From);
        VectorSubtract( end, start, vecStart2End);

        dot = DotProductNormalize( vecStart2From, vecStart2End );

        if ( dot <= 0 )
        {
                //The perpendicular would be beyond or through the start point
                VectorCopy( start, result );
                return qfalse;
        }

        if ( dot == 1 )
        {
                //parallel, closer of 2 points will be the target
                if( (VectorLengthSquared( vecStart2From )) < (VectorLengthSquared( vecStart2End )) )
                {
                        VectorCopy( from, result );
                }
                else
                {
                        VectorCopy( end, result );
                }
                return qfalse;
        }

        //Try other end
        VectorSubtract( from, end, vecEnd2From);
        VectorSubtract( start, end, vecEnd2Start);

        dot = DotProductNormalize( vecEnd2From, vecEnd2Start );

        if ( dot <= 0 )
        {//The perpendicular would be beyond or through the start point
                VectorCopy( end, result );
                return qfalse;
        }

        if ( dot == 1 )
        {//parallel, closer of 2 points will be the target
                if( (VectorLengthSquared( vecEnd2From )) < (VectorLengthSquared( vecEnd2Start )))
                {
                        VectorCopy( from, result );
                }
                else
                {
                        VectorCopy( end, result );
                }
                return qfalse;
        }

        //                    /|
        //                c  / |
        //                  /  |a
        //      theta  /)__|    
        //                    b
        //cos(theta) = b / c
        //solve for b
        //b = cos(theta) * c

        //angle between vecs end2from and end2start, should be between 0 and 90
        theta = 90 * (1 - dot);//theta
        
        //Get length of side from End2Result using sine of theta
        distEnd2From = VectorLength( vecEnd2From );//c
        cos_theta = cos(DEG2RAD(theta));//cos(theta)
        distEnd2Result = cos_theta * distEnd2From;//b

        //Extrapolate to find result
        VectorNormalize( vecEnd2Start );
        VectorMA( end, distEnd2Result, vecEnd2Start, result );
        
        //perpendicular intersection is between the 2 endpoints
        return qtrue;
}

float G_PointDistFromLineSegment( const vec3_t start, const vec3_t end, const vec3_t from )
{
        vec3_t  vecStart2From, vecStart2End, vecEnd2Start, vecEnd2From, intersection;
        float   distEnd2From, distStart2From, distEnd2Result, theta, cos_theta, dot;

        //Find the perpendicular vector to vec from start to end
        VectorSubtract( from, start, vecStart2From);
        VectorSubtract( end, start, vecStart2End);
        VectorSubtract( from, end, vecEnd2From);
        VectorSubtract( start, end, vecEnd2Start);

        dot = DotProductNormalize( vecStart2From, vecStart2End );

        distStart2From = Distance( start, from );
        distEnd2From = Distance( end, from );

        if ( dot <= 0 )
        {
                //The perpendicular would be beyond or through the start point
                return distStart2From;
        }

        if ( dot == 1 )
        {
                //parallel, closer of 2 points will be the target
                return ((distStart2From<distEnd2From)?distStart2From:distEnd2From);
        }

        //Try other end

        dot = DotProductNormalize( vecEnd2From, vecEnd2Start );

        if ( dot <= 0 )
        {//The perpendicular would be beyond or through the end point
                return distEnd2From;
        }

        if ( dot == 1 )
        {//parallel, closer of 2 points will be the target
                return ((distStart2From<distEnd2From)?distStart2From:distEnd2From);
        }

        //                    /|
        //                c  / |
        //                  /  |a
        //      theta  /)__|    
        //                    b
        //cos(theta) = b / c
        //solve for b
        //b = cos(theta) * c

        //angle between vecs end2from and end2start, should be between 0 and 90
        theta = 90 * (1 - dot);//theta
        
        //Get length of side from End2Result using sine of theta
        cos_theta = cos(DEG2RAD(theta));//cos(theta)
        distEnd2Result = cos_theta * distEnd2From;//b

        //Extrapolate to find result
        VectorNormalize( vecEnd2Start );
        VectorMA( end, distEnd2Result, vecEnd2Start, intersection );
        
        //perpendicular intersection is between the 2 endpoints, return dist to it from from
        return Distance( intersection, from );
}