rotate.c 1.31 KB
/**************************************************************************
 *									  *
 *		 Copyright (C) 1994, Silicon Graphics, Inc.		  *
 *									  *
 *  These coded instructions, statements, and computer programs  contain  *
 *  unpublished  proprietary  information of Silicon Graphics, Inc., and  *
 *  are protected by Federal copyright law.  They  may  not be disclosed  *
 *  to  third  parties  or copied or duplicated in any form, in whole or  *
 *  in part, without the prior written consent of Silicon Graphics, Inc.  *
 *									  *
 **************************************************************************/

#include "guint.h"

void guRotateF(float mf[4][4], float a, float x, float y, float z)
{
	static float	dtor = 3.1415926 / 180.0;
	float	sine;
	float	cosine;
	float	ab, bc, ca, t;

	guNormalize(&x, &y, &z);
	a *= dtor;
	sine = sinf(a);
	cosine = cosf(a);
	t = (1-cosine);
	ab = x*y*t;
	bc = y*z*t;
	ca = z*x*t;

	guMtxIdentF(mf);

	t = x*x;
	mf[0][0] = t+cosine*(1-t);
	mf[2][1] = bc-x*sine;
	mf[1][2] = bc+x*sine;

	t = y*y;
	mf[1][1] = t+cosine*(1-t);
	mf[2][0] = ca+y*sine;
	mf[0][2] = ca-y*sine;

	t = z*z;
	mf[2][2] = t+cosine*(1-t);
	mf[1][0] = ab-z*sine;
	mf[0][1] = ab+z*sine;
}

void guRotate(Mtx *m, float a, float x, float y, float z)
{
	Matrix	mf;

	guRotateF(mf, a, x, y, z);

	guMtxF2L(mf, m);
}