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root/radiance/ray/src/ot/o_instance.c
Revision: 2.5
Committed: Sat Mar 27 12:41:45 2004 UTC (20 years, 7 months ago) by schorsch
Content type: text/plain
Branch: MAIN
Changes since 2.4: +19 -11 lines
Log Message:
Continued ANSIfication. Renamed local initotypes() to ot_initotypes().

File Contents

# User Rev Content
1 greg 1.1 #ifndef lint
2 schorsch 2.5 static const char RCSid[] = "$Id: o_instance.c,v 2.4 2003/07/27 22:12:03 schorsch Exp $";
3 greg 1.1 #endif
4     /*
5 greg 2.3 * o_instance.c - routines for creating octrees for other octrees
6 greg 1.1 */
7    
8     #include "standard.h"
9    
10     #include "object.h"
11 greg 2.2
12     #include "octree.h"
13 greg 1.1
14     #include "instance.h"
15    
16 greg 2.3 #include "mesh.h"
17    
18 greg 1.1 #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 schorsch 2.5 static int o_cube(CUBE *cu1, FULLXF *fxf, CUBE *cu);
44    
45    
46 greg 2.3 static int
47 schorsch 2.5 o_cube( /* determine if cubes intersect */
48     CUBE *cu1,
49     FULLXF *fxf,
50     CUBE *cu
51     )
52 greg 1.1 {
53 greg 1.2 static int vstart[4] = {0, 3, 5, 6};
54 greg 1.1 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 greg 2.3 cumax[j] = (cumin[j] = cu1->cuorg[j]) + cu1->cusize;
62 greg 1.1 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 greg 2.3 multp3(v2, v1, fxf->b.xfm);
71 schorsch 2.4 if ( (j = plocate(v2, cumin, cumax)) )
72 greg 1.1 vout++;
73     vloc &= j;
74     }
75     if (vout == 0) /* all inside */
76 greg 1.3 return(O_IN);
77 greg 1.1 if (vout < 8) /* some inside */
78 greg 1.3 return(O_HIT);
79 greg 1.1 if (vloc) /* all to one side */
80 greg 1.3 return(O_MISS);
81 greg 1.1 /* 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 greg 2.3 v1[j] = cu1->cuorg[j];
88 greg 1.1 if (i & 1<<j)
89 greg 2.3 v1[j] += cu1->cusize;
90 greg 1.1 }
91 greg 2.3 multp3(vert[i], v1, fxf->f.xfm);
92 schorsch 2.4 if ( (j = plocate(vert[i], cumin, cumax)) )
93 greg 1.1 vloc &= j;
94     else
95 greg 1.3 return(O_HIT); /* vertex inside */
96 greg 1.1 }
97     if (vloc) /* all to one side */
98 greg 1.3 return(O_MISS);
99 greg 1.1 /* 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 greg 1.3 return(O_HIT); /* edge inside */
107 greg 1.1 }
108    
109 greg 1.3 return(O_MISS); /* no intersection */
110 greg 2.3 }
111    
112    
113 schorsch 2.5 /* XXX o_instance() is extern, but not declared in any header file */
114 greg 2.3 int
115 schorsch 2.5 o_instance( /* determine if instance intersects */
116     OBJREC *o,
117     CUBE *cu
118     )
119 greg 2.3 {
120     INSTANCE *ins;
121     /* get octree bounds */
122     ins = getinstance(o, IO_BOUNDS);
123     /* call o_cube to do the work */
124     return(o_cube(&ins->obj->scube, &ins->x, cu));
125     }
126    
127    
128 schorsch 2.5 /* XXX o_mesh() is extern, but not declared in any header file */
129 greg 2.3 int
130 schorsch 2.5 o_mesh( /* determine if mesh intersects */
131     OBJREC *o,
132     CUBE *cu
133     )
134 greg 2.3 {
135     MESHINST *mip;
136     /* get mesh bounds */
137     mip = getmeshinst(o, IO_BOUNDS);
138     /* call o_cube to do the work */
139     return(o_cube(&mip->msh->mcube, &mip->x, cu));
140 greg 1.1 }