76 lines
2.8 KiB
C
76 lines
2.8 KiB
C
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// Shadow Volume BSP code written by Forest "LordHavoc" Hale on 2003-11-06 and placed into public domain.
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// Modified by LordHavoc (to make it work and other nice things like that) on 2007-01-24 and 2007-01-25
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#ifndef SVBSP_H
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#define SVBSP_H
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typedef struct svbsp_node_s
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{
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// notes:
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// leaf nodes are not stored, these are always structural nodes
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// (they always have a plane and two children)
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// children[] can be -1 for empty leaf or -2 for shadow leaf, >= 0 is node
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// parent can be -1 if this is the root node, >= 0 is a node
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int parent, children[2], padding;
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// node plane, splits space
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float plane[4];
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}
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svbsp_node_t;
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typedef struct svbsp_s
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{
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// lightsource or view origin
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float origin[3];
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// current number of nodes in the svbsp
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int numnodes;
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// how big the nodes array is
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int maxnodes;
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// first node is the root node
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svbsp_node_t *nodes;
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// non-zero indicates that an insertion failed because of lack of nodes
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int ranoutofnodes;
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// tree statistics
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// note: do not use multithreading when gathering statistics!
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// (the code updating these counters is not thread-safe, increments may
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// sometimes fail when multithreaded)
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int stat_occluders_rejected;
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int stat_occluders_accepted;
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int stat_occluders_fragments_rejected;
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int stat_occluders_fragments_accepted;
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int stat_queries_rejected;
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int stat_queries_accepted;
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int stat_queries_fragments_rejected;
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int stat_queries_fragments_accepted;
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}
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svbsp_t;
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// this function initializes a tree to prepare for polygon insertions
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//
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// the maxnodes needed for a given polygon set can vary wildly, if there are
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// not enough maxnodes then later polygons will not be inserted and the field
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// svbsp_t->ranoutofnodes will be non-zero
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//
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// as a rule of thumb the minimum nodes needed for a polygon set is
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// numpolygons * (averagepolygonvertices + 1)
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void SVBSP_Init(svbsp_t *b, const float *origin, int maxnodes, svbsp_node_t *nodes);
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// this function tests if any part of a polygon is not in shadow, and returns
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// non-zero if the polygon is not completely shadowed
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//
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// returns 0 if the polygon was rejected (not facing origin or no points)
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// returns 1 if all of the polygon is in shadow
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// returns 2 if all of the polygon is unshadowed
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// returns 3 if some of the polygon is shadowed and some unshadowed
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//
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// it also can add a new shadow volume (insertoccluder parameter)
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//
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// additionally it calls your fragmentcallback on each unshadowed clipped
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// part of the polygon
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// (beware that polygons often get split heavily, even if entirely unshadowed)
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//
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// thread-safety notes: do not multi-thread insertions!
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int SVBSP_AddPolygon(svbsp_t *b, int numpoints, const float *points, int insertoccluder, void (*fragmentcallback)(void *fragmentcallback_pointer1, int fragmentcallback_number1, svbsp_t *b, int numpoints, const float *points), void *fragmentcallback_pointer1, int fragmentcallback_number1);
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#endif
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