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root/Development/ray/src/common/mat4.c

Comparing ray/src/common/mat4.c (file contents):
Revision 1.4 by greg, Thu Jan 18 23:58:56 1990 UTC vs.
Revision 2.4 by greg, Tue Feb 25 02:47:21 2003 UTC

#	Line 1 | Line 1
1	–	/* Copyright (c) 1986 Regents of the University of California */
2	–
1		#ifndef lint
2	<	static char SCCSid[] = "$SunId$ LBL";
2	>	static const char       RCSid[] = "$Id$";
3		#endif
6	–
4		/*
5		*  mat4.c - routines dealing with 4 X 4 homogeneous transformation matrices.
9	–	*
10	–	*     10/19/85
6		*/
7
8	+	#include "copyright.h"
9
10	<	static double  m4tmp[4][4];             /* for efficiency */
10	>	#include  "mat4.h"
11
12	<	#ifdef  BSD
17	<	#define  copymat4(m4a,m4b)      bcopy((char *)m4b,(char *)m4a,sizeof(m4tmp))
18	<	#else
19	<	#define  copymat4(m4a,m4b)      (void)memcpy((char *)m4a,(char *)m4b,sizeof(m4tmp))
20	<	extern char  *memcpy();
21	<	#endif
12	>	MAT4  m4ident = MAT4IDENT;
13
14	+	static MAT4  m4tmp;             /* for efficiency */
15
24	–	setident4(m4)
25	–	double  m4[4][4];
26	–	{
27	–	static double  ident[4][4] = {
28	–	1.,0.,0.,0.,
29	–	0.,1.,0.,0.,
30	–	0.,0.,1.,0.,
31	–	0.,0.,0.,1.,
32	–	};
33	–	copymat4(m4, ident);
34	–	}
16
17	<
17	>	void
18		multmat4(m4a, m4b, m4c)         /* multiply m4b X m4c and put into m4a */
19	<	double  m4a[4][4];
20	<	register double  m4b[4][4], m4c[4][4];
19	>	MAT4  m4a;
20	>	register MAT4  m4b, m4c;
21		{
22		register int  i, j;
23
#	Line 51 | Line 32 | register double  m4b[4][4], m4c[4][4];
32		}
33
34
35	+	void
36		multv3(v3a, v3b, m4)    /* transform vector v3b by m4 and put into v3a */
37	<	double  v3a[3];
38	<	register double  v3b[3];
39	<	register double  m4[4][4];
37	>	FVECT  v3a;
38	>	register FVECT  v3b;
39	>	register MAT4  m4;
40		{
41		m4tmp[0][0] = v3b[0]*m4[0][0] + v3b[1]*m4[1][0] + v3b[2]*m4[2][0];
42		m4tmp[0][1] = v3b[0]*m4[0][1] + v3b[1]*m4[1][1] + v3b[2]*m4[2][1];
#	Line 66 | Line 48 | register double  m4[4][4];
48		}
49
50
51	+	void
52		multp3(p3a, p3b, m4)            /* transform p3b by m4 and put into p3a */
53	<	register double  p3a[3];
54	<	double  p3b[3];
55	<	register double  m4[4][4];
53	>	register FVECT  p3a;
54	>	FVECT  p3b;
55	>	register MAT4  m4;
56		{
57		multv3(p3a, p3b, m4);   /* transform as vector */
58		p3a[0] += m4[3][0];     /* translate */
59		p3a[1] += m4[3][1];
60		p3a[2] += m4[3][2];
61		}
79	–
80	–
81	–	#ifdef  INVMAT
82	–	/*
83	–	* invmat - computes the inverse of mat into inverse.  Returns 1
84	–	* if there exists an inverse, 0 otherwise.  It uses Gaussian Elimination
85	–	* method with partial pivoting.
86	–	*/
87	–
88	–	invmat(inverse,mat)
89	–	double mat[4][4],inverse[4][4];
90	–	{
91	–	#define SWAP(a,b,t) (t=a,a=b,b=t)
92	–	#define ABS(x) (x>=0?x:-(x))
93	–
94	–	register int i,j,k;
95	–	register double temp;
96	–
97	–	copymat4(m4tmp, mat);
98	–	setident(inverse);
99	–
100	–	for(i = 0; i < 4; i++) {
101	–	/* Look for row with largest pivot and swap rows */
102	–	temp = 0; j = -1;
103	–	for(k = i; k < 4; k++)
104	–	if(ABS(m4tmp[k][i]) > temp) {
105	–	temp = ABS(m4tmp[k][i]);
106	–	j = k;
107	–	}
108	–	if(j == -1)     /* No replacing row -> no inverse */
109	–	return(0);
110	–	if (j != i)
111	–	for(k = 0; k < 4; k++) {
112	–	SWAP(m4tmp[i][k],m4tmp[j][k],temp);
113	–	SWAP(inverse[i][k],inverse[j][k],temp);
114	–	}
115	–
116	–	temp = m4tmp[i][i];
117	–	for(k = 0; k < 4; k++) {
118	–	m4tmp[i][k] /= temp;
119	–	inverse[i][k] /= temp;
120	–	}
121	–	for(j = 0; j < 4; j++) {
122	–	if(j != i) {
123	–	temp = m4tmp[j][i];
124	–	for(k = 0; k < 4; k++) {
125	–	m4tmp[j][k] -= m4tmp[i][k]*temp;
126	–	inverse[j][k] -= inverse[i][k]*temp;
127	–	}
128	–	}
129	–	}
130	–	}
131	–	return(1);
132	–
133	–	#undef ABS
134	–	#undef SWAP
135	–	}
136	–	#endif

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