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      1 /**************************************************************************
      2  *
      3  * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
      4  * All Rights Reserved.
      5  *
      6  * Permission is hereby granted, free of charge, to any person obtaining a
      7  * copy of this software and associated documentation files (the
      8  * "Software"), to deal in the Software without restriction, including
      9  * without limitation the rights to use, copy, modify, merge, publish,
     10  * distribute, sub license, and/or sell copies of the Software, and to
     11  * permit persons to whom the Software is furnished to do so, subject to
     12  * the following conditions:
     13  *
     14  * The above copyright notice and this permission notice (including the
     15  * next paragraph) shall be included in all copies or substantial portions
     16  * of the Software.
     17  *
     18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
     19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
     21  * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
     22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
     23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
     24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     25  *
     26  **************************************************************************/
     27 
     28  /*
     29   * Authors:
     30   *   Keith Whitwell <keith (at) tungstengraphics.com>
     31   */
     32 
     33 #include "draw/draw_context.h"
     34 #include "draw/draw_private.h"
     35 #include "draw/draw_pt.h"
     36 #include "util/u_debug.h"
     37 
     38 void draw_pt_split_prim(unsigned prim, unsigned *first, unsigned *incr)
     39 {
     40    switch (prim) {
     41    case PIPE_PRIM_POINTS:
     42       *first = 1;
     43       *incr = 1;
     44       break;
     45    case PIPE_PRIM_LINES:
     46       *first = 2;
     47       *incr = 2;
     48       break;
     49    case PIPE_PRIM_LINE_STRIP:
     50    case PIPE_PRIM_LINE_LOOP:
     51       *first = 2;
     52       *incr = 1;
     53       break;
     54    case PIPE_PRIM_LINES_ADJACENCY:
     55       *first = 4;
     56       *incr = 4;
     57       break;
     58    case PIPE_PRIM_LINE_STRIP_ADJACENCY:
     59       *first = 4;
     60       *incr = 1;
     61       break;
     62    case PIPE_PRIM_TRIANGLES:
     63       *first = 3;
     64       *incr = 3;
     65       break;
     66    case PIPE_PRIM_TRIANGLES_ADJACENCY:
     67       *first = 6;
     68       *incr = 6;
     69       break;
     70    case PIPE_PRIM_TRIANGLE_STRIP:
     71    case PIPE_PRIM_TRIANGLE_FAN:
     72    case PIPE_PRIM_POLYGON:
     73       *first = 3;
     74       *incr = 1;
     75       break;
     76    case PIPE_PRIM_TRIANGLE_STRIP_ADJACENCY:
     77       *first = 6;
     78       *incr = 2;
     79       break;
     80    case PIPE_PRIM_QUADS:
     81       *first = 4;
     82       *incr = 4;
     83       break;
     84    case PIPE_PRIM_QUAD_STRIP:
     85       *first = 4;
     86       *incr = 2;
     87       break;
     88    default:
     89       assert(0);
     90       *first = 0;
     91       *incr = 1;		/* set to one so that count % incr works */
     92       break;
     93    }
     94 }
     95 
     96 unsigned draw_pt_trim_count(unsigned count, unsigned first, unsigned incr)
     97 {
     98    if (count < first)
     99       return 0;
    100    return count - (count - first) % incr;
    101 }
    102