Show vector.c syntax highlighted
/*
* The 3D Studio File Format Library
* Copyright (C) 1996-2001 by J.E. Hoffmann <je-h@gmx.net>
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or (at
* your option) any later version.
*
* This program 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 Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* $Id: vector.c,v 1.9 2004/11/16 07:41:44 efalk Exp $
*/
#define LIB3DS_EXPORT
#include <lib3ds/vector.h>
#include <math.h>
/*!
* \defgroup vector Vector Mathematics
*
* \author J.E. Hoffmann <je-h@gmx.net>
*/
/*!
* \typedef Lib3dsVector
* \ingroup vector
*/
/*!
* Clear a vector to zero.
*
* \param c Vector to clear.
*
* \ingroup vector
*/
void
lib3ds_vector_zero(Lib3dsVector c)
{
int i;
for (i=0; i<3; ++i) {
c[i]=0.0f;
}
}
/*!
* Copy a vector.
*
* \param dest Destination vector.
* \param src Source vector.
*
* \ingroup vector
*/
void
lib3ds_vector_copy(Lib3dsVector dest, Lib3dsVector src)
{
int i;
for (i=0; i<3; ++i) {
dest[i]=src[i];
}
}
/*!
* Negate a vector.
*
* \param c Vector to negate.
*
* \ingroup vector
*/
void
lib3ds_vector_neg(Lib3dsVector c)
{
int i;
for (i=0; i<3; ++i) {
c[i]=-c[i];
}
}
/*!
* Add two vectors.
*
* \param c Result.
* \param a First addend.
* \param b Second addend.
*
* \ingroup vector
*/
void
lib3ds_vector_add(Lib3dsVector c, Lib3dsVector a, Lib3dsVector b)
{
int i;
for (i=0; i<3; ++i) {
c[i]=a[i]+b[i];
}
}
/*!
* Subtract two vectors.
*
* \param c Result.
* \param a Addend.
* \param b Minuend.
*
* \ingroup vector
*/
void
lib3ds_vector_sub(Lib3dsVector c, Lib3dsVector a, Lib3dsVector b)
{
int i;
for (i=0; i<3; ++i) {
c[i]=a[i]-b[i];
}
}
/*!
* Multiply a vector by a scalar.
*
* \param c Vector to be multiplied.
* \param k Scalar.
*
* \ingroup vector
*/
void
lib3ds_vector_scalar(Lib3dsVector c, Lib3dsFloat k)
{
int i;
for (i=0; i<3; ++i) {
c[i]*=k;
}
}
/*!
* Compute cross product.
*
* \param c Result.
* \param a First vector.
* \param b Second vector.
*
* \ingroup vector
*/
void
lib3ds_vector_cross(Lib3dsVector c, Lib3dsVector a, Lib3dsVector b)
{
c[0]=a[1]*b[2] - a[2]*b[1];
c[1]=a[2]*b[0] - a[0]*b[2];
c[2]=a[0]*b[1] - a[1]*b[0];
}
/*!
* Compute dot product.
*
* \param a First vector.
* \param b Second vector.
*
* \return Dot product.
*
* \ingroup vector
*/
Lib3dsFloat
lib3ds_vector_dot(Lib3dsVector a, Lib3dsVector b)
{
return(a[0]*b[0] + a[1]*b[1] + a[2]*b[2]);
}
/*!
* Compute square of vector.
*
* Computes x*x + y*y + z*z.
*
* \param c Vector to square.
*
* \return Square of vector.
*
* \ingroup vector
*/
Lib3dsFloat
lib3ds_vector_squared(Lib3dsVector c)
{
return(c[0]*c[0] + c[1]*c[1] + c[2]*c[2]);
}
/*!
* Compute length of vector.
*
* Computes |c| = sqrt(x*x + y*y + z*z)
*
* \param c Vector to compute.
*
* \return Length of vector.
*
* \ingroup vector
*/
Lib3dsFloat
lib3ds_vector_length(Lib3dsVector c)
{
return((Lib3dsFloat)sqrt(c[0]*c[0] + c[1]*c[1] + c[2]*c[2]));
}
/*!
* Normalize a vector.
*
* Scales a vector so that its length is 1.0.
*
* \param c Vector to normalize.
*
* \ingroup vector
*/
void
lib3ds_vector_normalize(Lib3dsVector c)
{
Lib3dsFloat l,m;
l=(Lib3dsFloat)sqrt(c[0]*c[0] + c[1]*c[1] + c[2]*c[2]);
if (fabs(l)<LIB3DS_EPSILON) {
if ((c[0]>=c[1]) && (c[0]>=c[2])) {
c[0]=1.0f;
c[1]=c[2]=0.0f;
}
else
if (c[1]>=c[2]) {
c[1]=1.0f;
c[0]=c[2]=0.0f;
}
else {
c[2]=1.0f;
c[0]=c[1]=0.0f;
}
}
else {
m=1.0f/l;
c[0]*=m;
c[1]*=m;
c[2]*=m;
}
}
/*!
* Compute a vector normal to two line segments.
*
* Computes the normal vector to the lines b-a and b-c.
*
* \param n Returned normal vector.
* \param a Endpoint of first line.
* \param b Base point of both lines.
* \param c Endpoint of second line.
*
* \ingroup vector
*/
void
lib3ds_vector_normal(Lib3dsVector n, Lib3dsVector a, Lib3dsVector b, Lib3dsVector c)
{
Lib3dsVector p,q;
lib3ds_vector_sub(p,c,b);
lib3ds_vector_sub(q,a,b);
lib3ds_vector_cross(n,p,q);
lib3ds_vector_normalize(n);
}
/*!
* Multiply a point by a transformation matrix.
*
* Applies the given transformation matrix to the given point. With some
* transformation matrices, a vector may also be transformed.
*
* \param c Result.
* \param m Transformation matrix.
* \param a Input point.
*
* \ingroup vector
*/
void
lib3ds_vector_transform(Lib3dsVector c, Lib3dsMatrix m, Lib3dsVector a)
{
c[0]= m[0][0]*a[0] + m[1][0]*a[1] + m[2][0]*a[2] + m[3][0];
c[1]= m[0][1]*a[0] + m[1][1]*a[1] + m[2][1]*a[2] + m[3][1];
c[2]= m[0][2]*a[0] + m[1][2]*a[1] + m[2][2]*a[2] + m[3][2];
}
/*!
* Compute a point on a cubic spline.
*
* Computes a point on a parametric Bezier spline.
*
* \param c Result.
* \param a First endpoint of the spline.
* \param p First tangent vector of the spline.
* \param q Second tangent vector of the spline.
* \param b Second endpoint of the spline.
* \param t Spline parameter [0. 1.]
*
* \ingroup vector
*/
void
lib3ds_vector_cubic(Lib3dsVector c, Lib3dsVector a, Lib3dsVector p, Lib3dsVector q,
Lib3dsVector b, Lib3dsFloat t)
{
Lib3dsDouble x,y,z,w;
x=2*t*t*t - 3*t*t + 1;
y=-2*t*t*t + 3*t*t;
z=t*t*t - 2*t*t + t;
w=t*t*t - t*t;
c[0]=(Lib3dsFloat)(x*a[0] + y*b[0] + z*p[0] + w*q[0]);
c[1]=(Lib3dsFloat)(x*a[1] + y*b[1] + z*p[1] + w*q[1]);
c[2]=(Lib3dsFloat)(x*a[2] + y*b[2] + z*p[2] + w*q[2]);
}
/*!
* c[i] = min(c[i], a[i]);
*
* Computes minimum values of x,y,z independently.
*
* \ingroup vector
*/
void
lib3ds_vector_min(Lib3dsVector c, Lib3dsVector a)
{
int i;
for (i=0; i<3; ++i) {
if (a[i]<c[i]) {
c[i] = a[i];
}
}
}
/*!
* c[i] = max(c[i], a[i]);
*
* Computes maximum values of x,y,z independently.
*
* \ingroup vector
*/
void
lib3ds_vector_max(Lib3dsVector c, Lib3dsVector a)
{
int i;
for (i=0; i<3; ++i) {
if (a[i]>c[i]) {
c[i] = a[i];
}
}
}
/*!
* \ingroup vector
*/
void
lib3ds_vector_dump(Lib3dsVector c)
{
fprintf(stderr, "%f %f %f\n", c[0], c[1], c[2]);
}
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