src/common/mesh.h

/* RCSid $Id: mesh.h,v 2.12 2004/01/30 00:08:31 greg Exp $ */
/*
 * Header for compact triangle mesh geometry
 *
 *  Include after standard.h, object.h and octree.h
 */
#ifndef _RAD_MESH_H_
#define _RAD_MESH_H_

#include "lookup.h"

#ifdef __cplusplus
extern "C" {
#endif

#ifndef BYTE
#define BYTE    unsigned char
#endif

/*
 * Vertex space is minimized without compromising accuracy by using a
 * 4-byte unsigned int to indicate position in the enclosing octree cube.
 * The same trick is used for any local (u,v) coordinates, whose limits
 * are recorded separately in the parent MESH structure.  The uvlimit's
 * in the MESH structure are set such that (0,0) is out of range, so
 * we use this to indicate an unspecified local coordinate.
 * A vertex normal, if specified, is stored in a single 4-byte
 * integer using the codec in dircode.c.  The encodedir() function
 * never generates 0, so we can use this for unspecified normals.
 *
 * Vertex ID's are encoded using the bottom 8 bits of a 4-byte integer
 * to index a vertex in a patch indicated by the 22 bits above (8-29).
 * For triangle ID's, the top 22 bits (10-31) indicate the parent patch,
 * and the 10th bit (0x200) indicates whether the triangle joins patches.
 * If not, then the bottom 9 bits index into the local PTri array.
 * If it's a joiner, then the 9th bit indicates whether the triangle joins
 * two patches, in which case the bottom 8 bits index the PJoin2 array.
 * Otherwise, the bottom 8 bits index the PJoin1 array.
 *
 * These shenanigans minimize vertex reference memory requirements
 * in compiled mesh structures, where the octree leaves contain sets 
 * of triangle ID's rather than the more usual objects.  It seems like
 * a lot of effort, but it can reduce mesh storage by a factor of 3
 * or more.  This is important, as the whole point is to model very
 * complicated geometry with this structure, and memory is the main
 * limitation.  (This representation is so efficient, that the octree
 * structure ends up dominating memory for most compiled meshes.)
 */

/* A triangle mesh patch */
typedef struct {
        uint32          (*xyz)[3];      /* up to 256 patch vertices */
        int32           *norm;          /* vertex normals */
        uint32          (*uv)[2];       /* vertex local coordinates */
        struct PTri {
                BYTE            v1, v2, v3;     /* local vertices */
        }               *tri;           /* local triangles */
        short           solemat;        /* sole material */
        int16           *trimat;        /* or local material indices */
        struct PJoin1 {
                int32           v1j;            /* non-local vertex */
                int16           mat;            /* material index */
                BYTE            v2, v3;         /* local vertices */
        }               *j1tri;         /* joiner triangles */
        struct PJoin2 {
                int32           v1j, v2j;       /* non-local vertices */
                int16           mat;            /* material index */
                BYTE            v3;             /* local vertex */
        }               *j2tri;         /* double joiner triangles */
        short           nverts;         /* vertex count */
        short           ntris;          /* local triangle count */
        short           nj1tris;        /* joiner triangle count */
        short           nj2tris;        /* double joiner triangle count */
} MESHPATCH;

/* A loaded mesh */
typedef struct mesh {
        char            *name;          /* mesh file name */
        int             nref;           /* reference count */
        int             ldflags;        /* what we've loaded */
        CUBE            mcube;          /* bounds and octree */
        RREAL           uvlim[2][2];    /* local coordinate extrema */
        OBJECT          mat0;           /* base material index */
        OBJECT          nmats;          /* number of materials */
        MESHPATCH       *patch;         /* allocated mesh patch array */
        int             npatches;       /* number of mesh patches */
        OBJREC          *pseudo;        /* mesh pseudo objects */
        LUTAB           lut;            /* vertex lookup table */
        struct mesh     *next;          /* next mesh in list */
} MESH;

/* A mesh instance */
typedef struct {
        FULLXF          x;              /* forward and backward transforms */
        MESH            *msh;           /* mesh object reference */
} MESHINST;

                                /* vertex flags */
#define MT_V            01
#define MT_N            02
#define MT_UV           04
#define MT_ALL          07

/* A mesh vertex */
typedef struct {
        int             fl;             /* setting flags */
        FVECT           v;              /* vertex location */
        FVECT           n;              /* vertex normal */
        RREAL           uv[2];          /* local coordinates */
} MESHVERT;

                                /* mesh format identifier */
#define MESHFMT         "Radiance_tmesh"
                                /* magic number for mesh files */
#define MESHMAGIC       ( 1 *MAXOBJSIZ+311)     /* increment first value */


extern MESH     *getmesh(char *mname, int flags);
extern MESHINST *getmeshinst(OBJREC *o, int flags);
extern int      getmeshtrivid(int32 tvid[3], OBJECT *mo,
                                MESH *mp, OBJECT ti);
extern int      getmeshvert(MESHVERT *vp, MESH *mp, int32 vid, int what);
extern int      getmeshtri(MESHVERT tv[3], OBJECT *mo,
                                MESH *mp, OBJECT ti, int what);
extern OBJREC   *getmeshpseudo(MESH *mp, OBJECT mo);
extern int32    addmeshvert(MESH *mp, MESHVERT *vp);
extern OBJECT   addmeshtri(MESH *mp, MESHVERT tv[3], OBJECT mo);
extern char     *checkmesh(MESH *mp);
extern void     printmeshstats(MESH *ms, FILE *fp);
extern void     freemesh(MESH *ms);
extern void     freemeshinst(OBJREC *o);
extern void     readmesh(MESH *mp, char *path, int flags);
extern void     writemesh(MESH *mp, FILE *fp);


#ifdef __cplusplus
}
#endif
#endif /* _RAD_MESH_H_ */
Revision:	2.13
Committed:	Fri Dec 3 18:36:17 2004 UTC (19 years, 11 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
#	User	Rev	Content
1	greg	2.13	/* RCSid $Id: mesh.h,v 2.12 2004/01/30 00:08:31 greg Exp $ */
2	greg	2.1	/*
3			* Header for compact triangle mesh geometry
4			*
5			* Include after standard.h, object.h and octree.h
6			*/
7	schorsch	2.5	#ifndef _RAD_MESH_H_
8			#define _RAD_MESH_H_
9	schorsch	2.9
10			#include "lookup.h"
11
12	schorsch	2.5	#ifdef __cplusplus
13			extern "C" {
14			#endif
15	greg	2.3
16	greg	2.1	#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	greg	2.2	* to index a vertex in a patch indicated by the 22 bits above (8-29).
33	greg	2.13	* 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	greg	2.1	* If not, then the bottom 9 bits index into the local PTri array.
36	greg	2.13	* If it's a joiner, then the 9th bit indicates whether the triangle joins
37	greg	2.1	* 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	greg	2.13	* limitation. (This representation is so efficient, that the octree
47			* structure ends up dominating memory for most compiled meshes.)
48	greg	2.1	*/
49
50			/* A triangle mesh patch */
51			typedef struct {
52	greg	2.6	uint32 (xyz)[3]; / up to 256 patch vertices */
53			int32 norm; / vertex normals */
54	greg	2.12	uint32 (uv)[2]; / vertex local coordinates */
55	greg	2.1	struct PTri {
56			BYTE v1, v2, v3; /* local vertices */
57			} tri; / local triangles */
58	greg	2.3	short solemat; /* sole material */
59	greg	2.6	int16 trimat; / or local material indices */
60	greg	2.1	struct PJoin1 {
61	greg	2.6	int32 v1j; /* non-local vertex */
62			int16 mat; /* material index */
63	greg	2.1	BYTE v2, v3; /* local vertices */
64			} j1tri; / joiner triangles */
65			struct PJoin2 {
66	greg	2.6	int32 v1j, v2j; /* non-local vertices */
67			int16 mat; /* material index */
68	greg	2.1	BYTE v3; /* local vertex */
69			} j2tri; / double joiner triangles */
70			short nverts; /* vertex count */
71	greg	2.10	short ntris; /* local triangle count */
72	greg	2.1	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	schorsch	2.7	RREAL uvlim[2][2]; /* local coordinate extrema */
83	greg	2.3	OBJECT mat0; /* base material index */
84			OBJECT nmats; /* number of materials */
85	greg	2.13	MESHPATCH patch; / allocated mesh patch array */
86	greg	2.1	int npatches; /* number of mesh patches */
87	greg	2.3	OBJREC pseudo; / mesh pseudo objects */
88			LUTAB lut; /* vertex lookup table */
89	greg	2.1	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	schorsch	2.7	RREAL uv[2]; /* local coordinates */
110	greg	2.1	} MESHVERT;
111
112			/* mesh format identifier */
113			#define MESHFMT "Radiance_tmesh"
114			/* magic number for mesh files */
115	greg	2.12	#define MESHMAGIC ( 1 MAXOBJSIZ+311) / increment first value */
116	greg	2.1
117
118			extern MESH getmesh(char mname, int flags);
119			extern MESHINST getmeshinst(OBJREC o, int flags);
120	greg	2.6	extern int getmeshtrivid(int32 tvid[3], OBJECT *mo,
121	greg	2.3	MESH *mp, OBJECT ti);
122	greg	2.6	extern int getmeshvert(MESHVERT vp, MESH mp, int32 vid, int what);
123	greg	2.3	extern int getmeshtri(MESHVERT tv[3], OBJECT *mo,
124			MESH *mp, OBJECT ti, int what);
125			extern OBJREC getmeshpseudo(MESH mp, OBJECT mo);
126	greg	2.6	extern int32 addmeshvert(MESH mp, MESHVERT vp);
127	greg	2.3	extern OBJECT addmeshtri(MESH *mp, MESHVERT tv[3], OBJECT mo);
128			extern char checkmesh(MESH mp);
129	greg	2.1	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	schorsch	2.5
136			#ifdef __cplusplus
137			}
138			#endif
139			#endif /* _RAD_MESH_H_ */