prj/cam/libsrc/portal/pt_clut.c

   1 /*
   2 @Copyright Looking Glass Studios, Inc.
   3 1996,1997,1998,1999,2000 Unpublished Work.
   4 */
   5
   6 // $Header: r:/t2repos/thief2/libsrc/portold/pt_clut.c,v 1.3 1996/09/10 18:25:19 buzzard Exp $
   7
   8 #include <lg.h>
   9 #include <port.h>
  10 #include <pt_clut.h>
  11 #include <string.h>
  12
  13   // pointer to user cluts
  14 uchar *pt_clut_list[256];
  15
  16   // number of cluts we keep cached
  17 #define CLUT_CACHE_SIZE    4
  18
  19   // length of clut chain we cache
  20 #define CLUT_CACHE_IDSIZE  8
  21
  22   // storage for the clut cache
  23 static uchar pt_clut_cache[CLUT_CACHE_SIZE][256];
  24
  25 static uchar pt_clut_cache_idlist[CLUT_CACHE_SIZE][CLUT_CACHE_IDSIZE];
  26 static uchar pt_clut_cache_idlist_len[CLUT_CACHE_SIZE];
  27
  28   // compare a clut chain with an idlist, assuming first one already matched
  29 static bool compare_clut_chain(ClutChain *cc, int n)
  30 {
  31    int i=0, len = pt_clut_cache_idlist_len[n];
  32    while (i < len) {
  33       if (cc->clut_id != pt_clut_cache_idlist[n][i])
  34          return FALSE;
  35       ++i;
  36       if (cc->clut_id2) {
  37          if (i >= len) return FALSE;
  38
  39          if (cc->clut_id2 != pt_clut_cache_idlist[n][i])
  40             return FALSE;
  41          ++i;
  42       }
  43       cc = cc->next;
  44       if (!cc)
  45          return i == n;
  46    }
  47    return FALSE;
  48 }
  49
  50 uchar *pt_get_clut(ClutChain *cc)
  51 {
  52    static int ref;
  53    int i, c;
  54
  55      // check if it's just a single clut
  56    if (!cc->next && !cc->clut_id2)
  57       return pt_clut_list[cc->clut_id];
  58
  59      // check if we already have this one cached
  60    c = cc->clut_id;
  61    for (i=0; i < CLUT_CACHE_SIZE; ++i)
  62       if (pt_clut_cache_idlist[i][0] == c && pt_clut_cache_idlist_len[i])
  63          if (compare_clut_chain(cc, i))
  64             return pt_clut_cache[i];
  65
  66      // cycle through to the next cache entry
  67      //   note lack of LRUness... who cares,
  68      //   this should be super rare if it every happens at all
  69    if (++ref == CLUT_CACHE_SIZE) ref = 0;
  70
  71    {
  72       uchar *dest = pt_clut_cache[ref];
  73       uchar *s1 = pt_clut_list[cc->clut_id];
  74       uchar *s2;
  75       int j, n;
  76
  77       pt_clut_cache_idlist[ref][0] = cc->clut_id;
  78
  79       if (cc->clut_id2) {
  80          s2 = pt_clut_list[cc->clut_id2];
  81          pt_clut_cache_idlist[ref][1] = cc->clut_id2;
  82          for (j=0; j < 256; ++j)
  83             dest[j] = s2[s1[j]];
  84          n = 2;
  85       } else {
  86          memcpy(dest, s1, 256);
  87          n = 1;
  88       }
  89
  90       while (cc->next) {
  91          cc = cc->next;
  92          if (n < CLUT_CACHE_IDSIZE)
  93             pt_clut_cache_idlist[ref][n] = cc->clut_id;
  94          ++n;
  95
  96          s2 = pt_clut_list[cc->clut_id];
  97          for (j=0; j < 256; ++j)
  98             dest[j] = s2[dest[j]];
  99
 100          if (cc->clut_id2) {
 101             if (n < CLUT_CACHE_IDSIZE)
 102                pt_clut_cache_idlist[ref][n] = cc->clut_id2;
 103             ++n;
 104
 105             s2 = pt_clut_list[cc->clut_id2];
 106             for (j=0; j < 256; ++j)
 107                dest[j] = s2[dest[j]];
 108          }
 109       }
 110
 111       pt_clut_cache_idlist_len[ref] = (n <= CLUT_CACHE_IDSIZE ? n : 0);
 112    }
 113
 114    return pt_clut_cache[ref];
 115 }