src/mesa/state_tracker/st_atom_stipple.c

   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,
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  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
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  24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  **************************************************************************/
  27
  28  /*
  29   * \brief polygon stipple state
  30   *
  31   * Authors:
  32   *   Brian Paul
  33   */
  34
  35
  36 #include "st_context.h"
  37 #include "st_atom.h"
  38 #include "pipe/p_context.h"
  39 #include "pipe/p_defines.h"
  40
  41
  42 /**
  43  * OpenGL's polygon stipple is indexed with window coordinates in which
  44  * the origin (0,0) is the lower-left corner of the window.
  45  * With Gallium, the origin is the upper-left corner of the window.
  46  * To convert GL's polygon stipple to what gallium expects we need to
  47  * invert the pattern vertically and rotate the stipple rows according
  48  * to the window height.
  49  */
  50 static void
  51 invert_stipple(GLuint dest[32], const GLuint src[32], GLuint winHeight)
  52 {
  53    GLuint i;
  54
  55    for (i = 0; i < 32; i++) {
  56       dest[i] = src[(winHeight - 1 - i) & 0x1f];
  57    }
  58 }
  59
  60
  61
  62 static void
  63 update_stipple( struct st_context *st )
  64 {
  65    const GLuint sz = sizeof(st->state.poly_stipple);
  66    assert(sz == sizeof(st->ctx->PolygonStipple));
  67
  68    if (memcmp(st->state.poly_stipple, st->ctx->PolygonStipple, sz)) {
  69       /* state has changed */
  70       struct pipe_poly_stipple newStipple;
  71
  72       memcpy(st->state.poly_stipple, st->ctx->PolygonStipple, sz);
  73
  74       invert_stipple(newStipple.stipple, st->ctx->PolygonStipple,
  75                      st->ctx->DrawBuffer->Height);
  76
  77       st->pipe->set_polygon_stipple(st->pipe, &newStipple);
  78    }
  79 }
  80
  81
  82 /** Update the stipple when the pattern or window height changes */
  83 const struct st_tracked_state st_update_polygon_stipple = {
  84    "st_update_polygon_stipple",                         /* name */
  85    {                                                    /* dirty */
  86       (_NEW_POLYGONSTIPPLE |
  87        _NEW_BUFFERS),                                   /* mesa */
  88       0,                                                /* st */
  89    },
  90    update_stipple                                       /* update */
  91 };