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greg |
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/* RCSid $Id$ */
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/*
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* Header for compact triangle mesh geometry
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*
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* Include after standard.h, object.h and octree.h
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*/
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#include "copyright.h"
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#ifndef uint4
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#define uint4 unsigned int4
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#endif
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#ifndef BYTE
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#define BYTE unsigned char
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#endif
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/*
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* Vertex space is minimized without compromising accuracy by using a
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* 4-byte unsigned int to indicate position in the enclosing octree cube.
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* The same trick is used for any local (u,v) coordinates, whose limits
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* are recorded separately in the parent MESH structure. The uvlimit's
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* in the MESH structure are set such that (0,0) is out of range, so
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* we use this to indicate an unspecified local coordinate.
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* A vertex normal, if specified, is stored in a single 4-byte
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* integer using the codec in dircode.c. The encodedir() function
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* never generates 0, so we can use this for unspecified normals.
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*
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* Vertex ID's are encoded using the bottom 8 bits of a 4-byte integer
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* to index a vertex in a patch indicated by the 20 bits above (9-29).
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* For triangle ID's, the top 10 bits (11-31) indicate the patch, and
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* the 10th bit indicates whether the triangle joins patches.
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* If not, then the bottom 9 bits index into the local PTri array.
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* If it's a joiner, then the 9th bit indicates whether the triangle joins
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* two patches, in which case the bottom 8 bits index the PJoin2 array.
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* Otherwise, the bottom 8 bits index the PJoin1 array.
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*
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* These shenanigans minimize vertex reference memory requirements
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* in compiled mesh structures, where the octree leaves contain sets
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* of triangle ID's rather than the more usual objects. It seems like
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* a lot of effort, but it can reduce mesh storage by a factor of 3
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* or more. This is important, as the whole point is to model very
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* complicated geometry with this structure, and memory is the main
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* limitation. (We also optimize intersection tests for triangles.)
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*/
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/* A triangle mesh patch */
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typedef struct {
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uint4 (*xyz)[3]; /* up to 256 patch vertices */
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int4 *norm; /* vertex normals */
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uint4 (*uv)[2]; /* vertex local coordinates */
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struct PTri {
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BYTE v1, v2, v3; /* local vertices */
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} *tri; /* local triangles */
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struct PJoin1 {
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int4 v1j; /* non-local vertex */
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BYTE v2, v3; /* local vertices */
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} *j1tri; /* joiner triangles */
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struct PJoin2 {
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int4 v1j, v2j; /* non-local vertices */
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BYTE v3; /* local vertex */
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} *j2tri; /* double joiner triangles */
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short nverts; /* vertex count */
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short ntris; /* triangle count */
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short nj1tris; /* joiner triangle count */
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short nj2tris; /* double joiner triangle count */
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} MESHPATCH;
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/* A loaded mesh */
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typedef struct mesh {
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char *name; /* mesh file name */
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int nref; /* reference count */
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int ldflags; /* what we've loaded */
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CUBE mcube; /* bounds and octree */
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FLOAT uvlim[2][2]; /* local coordinate extrema */
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MESHPATCH *patch; /* mesh patch list */
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int npatches; /* number of mesh patches */
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char *cdata; /* opaque client data pointer */
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struct mesh *next; /* next mesh in list */
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} MESH;
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/* A mesh instance */
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typedef struct {
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FULLXF x; /* forward and backward transforms */
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MESH *msh; /* mesh object reference */
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} MESHINST;
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/* vertex flags */
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#define MT_V 01
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#define MT_N 02
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#define MT_UV 04
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#define MT_ALL 07
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/* A mesh vertex */
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typedef struct {
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int fl; /* setting flags */
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FVECT v; /* vertex location */
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FVECT n; /* vertex normal */
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FLOAT uv[2]; /* local coordinates */
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} MESHVERT;
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/* mesh format identifier */
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#define MESHFMT "Radiance_tmesh"
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/* magic number for mesh files */
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#define MESHMAGIC ( 0 *MAXOBJSIZ+311) /* increment first value */
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#ifdef NOPROTO
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extern MESH *getmesh();
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extern INSTANCE *getmeshinst();
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extern int getmeshtrivid();
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extern int getmeshvert();
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extern int getmeshtri();
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extern int4 addmeshvert();
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extern OBJECT addmeshtri();
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extern void printmeshstats();
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extern void freemesh();
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extern void freemeshinst();
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extern void readmesh();
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extern void writemesh();
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#else
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extern MESH *getmesh(char *mname, int flags);
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extern MESHINST *getmeshinst(OBJREC *o, int flags);
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extern int getmeshtrivid(int4 tvid[3], MESH *mp, OBJECT ti);
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extern int getmeshvert(MESHVERT *vp, MESH *mp, int4 vid, int what);
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extern int getmeshtri(MESHVERT tv[3], MESH *mp, OBJECT ti, int what);
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extern int4 addmeshvert(MESH *mp, MESHVERT *vp);
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extern OBJECT addmeshtri(MESH *mp, MESHVERT tv[3]);
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extern void printmeshstats(MESH *ms, FILE *fp);
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extern void freemesh(MESH *ms);
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extern void freemeshinst(OBJREC *o);
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extern void readmesh(MESH *mp, char *path, int flags);
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extern void writemesh(MESH *mp, FILE *fp);
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#endif /* NOPROTO */
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