src/gallium/drivers/nouveau/nouveau_util.h

   1 #ifndef __NOUVEAU_UTIL_H__
   2 #define __NOUVEAU_UTIL_H__
   3
   4 /* Determine how many vertices can be pushed into the command stream.
   5  * Where the remaining space isn't large enough to represent all verices,
   6  * split the buffer at primitive boundaries.
   7  *
   8  * Returns a count of vertices that can be rendered, and an index to
   9  * restart drawing at after a flush.
  10  */
  11 static INLINE unsigned
  12 nouveau_vbuf_split(unsigned remaining, unsigned overhead, unsigned vpp,
  13                    unsigned mode, unsigned start, unsigned count,
  14                    unsigned *restart)
  15 {
  16         int max, adj = 0;
  17
  18         max  = remaining - overhead;
  19         if (max < 0)
  20                 return 0;
  21
  22         max *= vpp;
  23         if (max >= count)
  24                 return count;
  25
  26         switch (mode) {
  27         case PIPE_PRIM_POINTS:
  28                 break;
  29         case PIPE_PRIM_LINES:
  30                 max = max & 1;
  31                 break;
  32         case PIPE_PRIM_TRIANGLES:
  33                 max = max - (max % 3);
  34                 break;
  35         case PIPE_PRIM_QUADS:
  36                 max = max & 3;
  37                 break;
  38         case PIPE_PRIM_LINE_LOOP:
  39         case PIPE_PRIM_LINE_STRIP:
  40                 if (max < 2)
  41                         max = 0;
  42                 adj = 1;
  43                 break;
  44         case PIPE_PRIM_POLYGON:
  45         case PIPE_PRIM_TRIANGLE_STRIP:
  46         case PIPE_PRIM_TRIANGLE_FAN:
  47                 if (max < 3)
  48                         max = 0;
  49                 adj = 2;
  50                 break;
  51         case PIPE_PRIM_QUAD_STRIP:
  52                 if (max < 4)
  53                         max = 0;
  54                 adj = 3;
  55                 break;
  56         default:
  57                 assert(0);
  58         }
  59
  60         *restart = start + max - adj;
  61         return max;
  62 }
  63
  64 /* Integer base-2 logarithm, rounded towards zero. */
  65 static INLINE unsigned log2i(unsigned i)
  66 {
  67         unsigned r = 0;
  68
  69         if (i & 0xffff0000) {
  70                 i >>= 16;
  71                 r += 16;
  72         }
  73         if (i & 0x0000ff00) {
  74                 i >>= 8;
  75                 r += 8;
  76         }
  77         if (i & 0x000000f0) {
  78                 i >>= 4;
  79                 r += 4;
  80         }
  81         if (i & 0x0000000c) {
  82                 i >>= 2;
  83                 r += 2;
  84         }
  85         if (i & 0x00000002) {
  86                 r += 1;
  87         }
  88         return r;
  89 }
  90
  91 struct u_split_prim {
  92    void *priv;
  93    void (*emit)(void *priv, unsigned start, unsigned count);
  94    void (*edge)(void *priv, boolean enabled);
  95
  96    unsigned mode;
  97    unsigned start;
  98    unsigned p_start;
  99    unsigned p_end;
 100
 101    int repeat_first:1;
 102    int close_first:1;
 103    int edgeflag_off:1;
 104 };
 105
 106 static inline void
 107 u_split_prim_init(struct u_split_prim *s,
 108                   unsigned mode, unsigned start, unsigned count)
 109 {
 110    if (mode == PIPE_PRIM_LINE_LOOP) {
 111       s->mode = PIPE_PRIM_LINE_STRIP;
 112       s->close_first = 1;
 113    } else {
 114       s->mode = mode;
 115       s->close_first = 0;
 116    }
 117    s->start = start;
 118    s->p_start = start;
 119    s->p_end = start + count;
 120    s->edgeflag_off = 0;
 121    s->repeat_first = 0;
 122 }
 123
 124 static INLINE boolean
 125 u_split_prim_next(struct u_split_prim *s, unsigned max_verts)
 126 {
 127    int repeat = 0;
 128
 129    if (s->repeat_first) {
 130       s->emit(s->priv, s->start, 1);
 131       max_verts--;
 132       if (s->edgeflag_off) {
 133          s->edge(s->priv, TRUE);
 134          s->edgeflag_off = FALSE;
 135       }
 136    }
 137
 138    if (s->p_start + s->close_first + max_verts >= s->p_end) {
 139       s->emit(s->priv, s->p_start, s->p_end - s->p_start);
 140       if (s->close_first)
 141          s->emit(s->priv, s->start, 1);
 142       return TRUE;
 143    }
 144
 145    switch (s->mode) {
 146    case PIPE_PRIM_LINES:
 147       max_verts &= ~1;
 148       break;
 149    case PIPE_PRIM_LINE_STRIP:
 150       repeat = 1;
 151       break;
 152    case PIPE_PRIM_POLYGON:
 153       max_verts--;
 154       s->emit(s->priv, s->p_start, max_verts);
 155       s->edge(s->priv, FALSE);
 156       s->emit(s->priv, s->p_start + max_verts, 1);
 157       s->p_start += max_verts;
 158       s->repeat_first = TRUE;
 159       s->edgeflag_off = TRUE;
 160       return FALSE;
 161    case PIPE_PRIM_TRIANGLES:
 162       max_verts = max_verts - (max_verts % 3);
 163       break;
 164    case PIPE_PRIM_TRIANGLE_STRIP:
 165       /* to ensure winding stays correct, always split
 166        * on an even number of generated triangles
 167        */
 168       max_verts = max_verts & ~1;
 169       repeat = 2;
 170       break;
 171    case PIPE_PRIM_TRIANGLE_FAN:
 172       s->repeat_first = TRUE;
 173       repeat = 1;
 174       break;
 175    case PIPE_PRIM_QUADS:
 176       max_verts &= ~3;
 177       break;
 178    case PIPE_PRIM_QUAD_STRIP:
 179       max_verts &= ~1;
 180       repeat = 2;
 181       break;
 182    default:
 183       break;
 184    }
 185
 186    s->emit (s->priv, s->p_start, max_verts);
 187    s->p_start += (max_verts - repeat);
 188    return FALSE;
 189 }
 190
 191 #endif