ViewVC Help
View File | Revision Log | Show Annotations | Download File | Root Listing
root/radiance/ray/src/common/mesh.h
Revision: 2.13
Committed: Fri Dec 3 18:36:17 2004 UTC (19 years, 3 months ago) by greg
Content type: text/plain
Branch: MAIN
CVS Tags: rad3R7P2, rad3R7P1, rad4R0, rad3R8, rad3R9
Changes since 2.12: +7 -6 lines
Log Message:
Improved comments

File Contents

# Content
1 /* RCSid $Id: mesh.h,v 2.12 2004/01/30 00:08:31 greg Exp $ */
2 /*
3 * Header for compact triangle mesh geometry
4 *
5 * Include after standard.h, object.h and octree.h
6 */
7 #ifndef _RAD_MESH_H_
8 #define _RAD_MESH_H_
9
10 #include "lookup.h"
11
12 #ifdef __cplusplus
13 extern "C" {
14 #endif
15
16 #ifndef BYTE
17 #define BYTE unsigned char
18 #endif
19
20 /*
21 * Vertex space is minimized without compromising accuracy by using a
22 * 4-byte unsigned int to indicate position in the enclosing octree cube.
23 * The same trick is used for any local (u,v) coordinates, whose limits
24 * are recorded separately in the parent MESH structure. The uvlimit's
25 * in the MESH structure are set such that (0,0) is out of range, so
26 * we use this to indicate an unspecified local coordinate.
27 * A vertex normal, if specified, is stored in a single 4-byte
28 * integer using the codec in dircode.c. The encodedir() function
29 * never generates 0, so we can use this for unspecified normals.
30 *
31 * Vertex ID's are encoded using the bottom 8 bits of a 4-byte integer
32 * to index a vertex in a patch indicated by the 22 bits above (8-29).
33 * For triangle ID's, the top 22 bits (10-31) indicate the parent patch,
34 * and the 10th bit (0x200) indicates whether the triangle joins patches.
35 * If not, then the bottom 9 bits index into the local PTri array.
36 * If it's a joiner, then the 9th bit indicates whether the triangle joins
37 * two patches, in which case the bottom 8 bits index the PJoin2 array.
38 * Otherwise, the bottom 8 bits index the PJoin1 array.
39 *
40 * These shenanigans minimize vertex reference memory requirements
41 * in compiled mesh structures, where the octree leaves contain sets
42 * of triangle ID's rather than the more usual objects. It seems like
43 * a lot of effort, but it can reduce mesh storage by a factor of 3
44 * or more. This is important, as the whole point is to model very
45 * complicated geometry with this structure, and memory is the main
46 * limitation. (This representation is so efficient, that the octree
47 * structure ends up dominating memory for most compiled meshes.)
48 */
49
50 /* A triangle mesh patch */
51 typedef struct {
52 uint32 (*xyz)[3]; /* up to 256 patch vertices */
53 int32 *norm; /* vertex normals */
54 uint32 (*uv)[2]; /* vertex local coordinates */
55 struct PTri {
56 BYTE v1, v2, v3; /* local vertices */
57 } *tri; /* local triangles */
58 short solemat; /* sole material */
59 int16 *trimat; /* or local material indices */
60 struct PJoin1 {
61 int32 v1j; /* non-local vertex */
62 int16 mat; /* material index */
63 BYTE v2, v3; /* local vertices */
64 } *j1tri; /* joiner triangles */
65 struct PJoin2 {
66 int32 v1j, v2j; /* non-local vertices */
67 int16 mat; /* material index */
68 BYTE v3; /* local vertex */
69 } *j2tri; /* double joiner triangles */
70 short nverts; /* vertex count */
71 short ntris; /* local triangle count */
72 short nj1tris; /* joiner triangle count */
73 short nj2tris; /* double joiner triangle count */
74 } MESHPATCH;
75
76 /* A loaded mesh */
77 typedef struct mesh {
78 char *name; /* mesh file name */
79 int nref; /* reference count */
80 int ldflags; /* what we've loaded */
81 CUBE mcube; /* bounds and octree */
82 RREAL uvlim[2][2]; /* local coordinate extrema */
83 OBJECT mat0; /* base material index */
84 OBJECT nmats; /* number of materials */
85 MESHPATCH *patch; /* allocated mesh patch array */
86 int npatches; /* number of mesh patches */
87 OBJREC *pseudo; /* mesh pseudo objects */
88 LUTAB lut; /* vertex lookup table */
89 struct mesh *next; /* next mesh in list */
90 } MESH;
91
92 /* A mesh instance */
93 typedef struct {
94 FULLXF x; /* forward and backward transforms */
95 MESH *msh; /* mesh object reference */
96 } MESHINST;
97
98 /* vertex flags */
99 #define MT_V 01
100 #define MT_N 02
101 #define MT_UV 04
102 #define MT_ALL 07
103
104 /* A mesh vertex */
105 typedef struct {
106 int fl; /* setting flags */
107 FVECT v; /* vertex location */
108 FVECT n; /* vertex normal */
109 RREAL uv[2]; /* local coordinates */
110 } MESHVERT;
111
112 /* mesh format identifier */
113 #define MESHFMT "Radiance_tmesh"
114 /* magic number for mesh files */
115 #define MESHMAGIC ( 1 *MAXOBJSIZ+311) /* increment first value */
116
117
118 extern MESH *getmesh(char *mname, int flags);
119 extern MESHINST *getmeshinst(OBJREC *o, int flags);
120 extern int getmeshtrivid(int32 tvid[3], OBJECT *mo,
121 MESH *mp, OBJECT ti);
122 extern int getmeshvert(MESHVERT *vp, MESH *mp, int32 vid, int what);
123 extern int getmeshtri(MESHVERT tv[3], OBJECT *mo,
124 MESH *mp, OBJECT ti, int what);
125 extern OBJREC *getmeshpseudo(MESH *mp, OBJECT mo);
126 extern int32 addmeshvert(MESH *mp, MESHVERT *vp);
127 extern OBJECT addmeshtri(MESH *mp, MESHVERT tv[3], OBJECT mo);
128 extern char *checkmesh(MESH *mp);
129 extern void printmeshstats(MESH *ms, FILE *fp);
130 extern void freemesh(MESH *ms);
131 extern void freemeshinst(OBJREC *o);
132 extern void readmesh(MESH *mp, char *path, int flags);
133 extern void writemesh(MESH *mp, FILE *fp);
134
135
136 #ifdef __cplusplus
137 }
138 #endif
139 #endif /* _RAD_MESH_H_ */