cm_patch.h

/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.
 
This file is part of Quake III Arena source code.
 
Quake III Arena source code is free software; you can redistribute it
and/or modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the License,
or (at your option) any later version.
 
Quake III Arena source code is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
 
You should have received a copy of the GNU General Public License
along with Quake III Arena source code; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/
 
//#define   CULL_BBOX
 
/*
 
This file does not reference any globals, and has these entry points:
 
void CM_ClearLevelPatches( void );
struct patchCollide_s   *CM_GeneratePatchCollide( int width, int height, const vec3_t *points );
void CM_TraceThroughPatchCollide( traceWork_t *tw, const struct patchCollide_s *pc );
qboolean CM_PositionTestInPatchCollide( traceWork_t *tw, const struct patchCollide_s *pc );
void CM_DrawDebugSurface( void (*drawPoly)(int color, int numPoints, flaot *points) );
 
 
Issues for collision against curved surfaces:
 
Surface edges need to be handled differently than surface planes
 
Plane expansion causes raw surfaces to expand past expanded bounding box
 
Position test of a volume against a surface is tricky.
 
Position test of a point against a surface is not well defined, because the surface has no volume.
 
 
Tracing leading edge points instead of volumes?
Position test by tracing corner to corner? (8*7 traces -- ouch)
 
coplanar edges
triangulated patches
degenerate patches
 
  endcaps
  degenerate
 
WARNING: this may misbehave with meshes that have rows or columns that only
degenerate a few triangles.  Completely degenerate rows and columns are handled
properly.
*/
 
 
#define MAX_FACETS          1024
// Changed in OPM
//  In OG it's 4096, however due to a tiny floating point difference
//  between x86 and x64, more patch planes can appear in x64
#define MAX_PATCH_PLANES    6144
 
typedef struct {
    float   plane[4];
    int     signbits;       // signx + (signy<<1) + (signz<<2), used as lookup during collision
} patchPlane_t;
 
typedef struct {
    int         surfacePlane;
    int         numBorders;     // 3 or four + 6 axial bevels + 4 or 3 * 4 edge bevels
    int         borderPlanes[4+6+16];
    int         borderInward[4+6+16];
    qboolean    borderNoAdjust[4+6+16];
} facet_t;
 
typedef struct patchCollide_s {
    vec3_t  bounds[2];
    int     numPlanes;          // surface planes plus edge planes
    patchPlane_t    *planes;
    int     numFacets;
    facet_t  *facets;
} patchCollide_t;
 
 
#define MAX_GRID_SIZE   129
 
typedef struct {
    int         width;
    int         height;
    qboolean    wrapWidth;
    qboolean    wrapHeight;
    vec3_t  points[MAX_GRID_SIZE][MAX_GRID_SIZE];   // [width][height]
} cGrid_t;
 
#define SUBDIVIDE_DISTANCE  16  //4 // never more than this units away from curve
#define PLANE_TRI_EPSILON   0.1
#define WRAP_POINT_EPSILON  0.1
 
 
patchCollide_t *CM_GeneratePatchCollide( int width, int height, vec3_t *points, float subdivisions );