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root/radiance/ray/src/ot/o_instance.c
Revision: 2.6
Committed: Tue Mar 30 16:13:00 2004 UTC (20 years ago) by schorsch
Content type: text/plain
Branch: MAIN
CVS Tags: rad5R4, rad5R2, rad4R2P2, rad5R0, rad5R1, rad3R7P2, rad3R7P1, rad4R2, rad4R1, rad4R0, rad3R6, rad3R6P1, rad3R8, rad3R9, rad4R2P1, rad5R3, HEAD
Changes since 2.5: +1 -3 lines
Log Message:
Continued ANSIfication. There are only bits and pieces left now.

File Contents

# Content
1 #ifndef lint
2 static const char RCSid[] = "$Id: o_instance.c,v 2.5 2004/03/27 12:41:45 schorsch Exp $";
3 #endif
4 /*
5 * o_instance.c - routines for creating octrees for other octrees
6 */
7
8 #include "standard.h"
9
10 #include "object.h"
11
12 #include "octree.h"
13
14 #include "instance.h"
15
16 #include "mesh.h"
17
18 #include "plocate.h"
19
20 /*
21 * To determine if two cubes intersect:
22 *
23 * 1) Check to see if any vertices of first cube are inside the
24 * second (intersection).
25 *
26 * 2) Check to see if all vertices of first are to one side of
27 * second (no intersection).
28 *
29 * 3) Perform 1 and 2 with roles reversed.
30 *
31 * 4) Check to see if any portion of any edge of second is inside
32 * first (intersection).
33 *
34 * 5) If test 4 fails, we have no intersection.
35 *
36 * Note that if we were testing two boxes, we would need
37 * to check that neither had any edges inside the other to be sure.
38 * Since an octree is a volume rather than a surface, we will
39 * return a value of 2 if the cube is entirely within the octree.
40 */
41
42
43 static int o_cube(CUBE *cu1, FULLXF *fxf, CUBE *cu);
44
45
46 static int
47 o_cube( /* determine if cubes intersect */
48 CUBE *cu1,
49 FULLXF *fxf,
50 CUBE *cu
51 )
52 {
53 static int vstart[4] = {0, 3, 5, 6};
54 FVECT cumin, cumax;
55 FVECT vert[8];
56 FVECT v1, v2;
57 int vloc, vout;
58 register int i, j;
59 /* check if cube vertex in octree */
60 for (j = 0; j < 3; j++)
61 cumax[j] = (cumin[j] = cu1->cuorg[j]) + cu1->cusize;
62 vloc = ABOVE | BELOW;
63 vout = 0;
64 for (i = 0; i < 8; i++) {
65 for (j = 0; j < 3; j++) {
66 v1[j] = cu->cuorg[j];
67 if (i & 1<<j)
68 v1[j] += cu->cusize;
69 }
70 multp3(v2, v1, fxf->b.xfm);
71 if ( (j = plocate(v2, cumin, cumax)) )
72 vout++;
73 vloc &= j;
74 }
75 if (vout == 0) /* all inside */
76 return(O_IN);
77 if (vout < 8) /* some inside */
78 return(O_HIT);
79 if (vloc) /* all to one side */
80 return(O_MISS);
81 /* octree vertices in cube? */
82 for (j = 0; j < 3; j++)
83 cumax[j] = (cumin[j] = cu->cuorg[j]) + cu->cusize;
84 vloc = ABOVE | BELOW;
85 for (i = 0; i < 8; i++) {
86 for (j = 0; j < 3; j++) {
87 v1[j] = cu1->cuorg[j];
88 if (i & 1<<j)
89 v1[j] += cu1->cusize;
90 }
91 multp3(vert[i], v1, fxf->f.xfm);
92 if ( (j = plocate(vert[i], cumin, cumax)) )
93 vloc &= j;
94 else
95 return(O_HIT); /* vertex inside */
96 }
97 if (vloc) /* all to one side */
98 return(O_MISS);
99 /* check edges */
100 for (i = 0; i < 4; i++)
101 for (j = 0; j < 3; j++) {
102 /* clip modifies vertices! */
103 VCOPY(v1, vert[vstart[i]]);
104 VCOPY(v2, vert[vstart[i] ^ 1<<j]);
105 if (clip(v1, v2, cumin, cumax))
106 return(O_HIT); /* edge inside */
107 }
108
109 return(O_MISS); /* no intersection */
110 }
111
112
113 int
114 o_instance( /* determine if instance intersects */
115 OBJREC *o,
116 CUBE *cu
117 )
118 {
119 INSTANCE *ins;
120 /* get octree bounds */
121 ins = getinstance(o, IO_BOUNDS);
122 /* call o_cube to do the work */
123 return(o_cube(&ins->obj->scube, &ins->x, cu));
124 }
125
126
127 int
128 o_mesh( /* determine if mesh intersects */
129 OBJREC *o,
130 CUBE *cu
131 )
132 {
133 MESHINST *mip;
134 /* get mesh bounds */
135 mip = getmeshinst(o, IO_BOUNDS);
136 /* call o_cube to do the work */
137 return(o_cube(&mip->msh->mcube, &mip->x, cu));
138 }