src/mesa/state_tracker/st_atom_scissor.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2007 VMware, Inc.
   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
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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 VMWARE 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   * Authors:
  30   *   Keith Whitwell <keithw@vmware.com>
  31   */
  32
  33
  34 #include "main/macros.h"
  35 #include "st_context.h"
  36 #include "pipe/p_context.h"
  37 #include "st_atom.h"
  38
  39
  40 /**
  41  * Scissor depends on the scissor box, and the framebuffer dimensions.
  42  */
  43 static void
  44 update_scissor( struct st_context *st )
  45 {
  46    struct pipe_scissor_state scissor[PIPE_MAX_VIEWPORTS];
  47    const struct gl_context *ctx = st->ctx;
  48    const struct gl_framebuffer *fb = ctx->DrawBuffer;
  49    GLint miny, maxy;
  50    unsigned i;
  51    bool changed = false;
  52    for (i = 0 ; i < ctx->Const.MaxViewports; i++) {
  53       scissor[i].minx = 0;
  54       scissor[i].miny = 0;
  55       scissor[i].maxx = fb->Width;
  56       scissor[i].maxy = fb->Height;
  57
  58       if (ctx->Scissor.EnableFlags & (1 << i)) {
  59          /* need to be careful here with xmax or ymax < 0 */
  60          GLint xmax = MAX2(0, ctx->Scissor.ScissorArray[i].X + ctx->Scissor.ScissorArray[i].Width);
  61          GLint ymax = MAX2(0, ctx->Scissor.ScissorArray[i].Y + ctx->Scissor.ScissorArray[i].Height);
  62
  63          if (ctx->Scissor.ScissorArray[i].X > (GLint)scissor[i].minx)
  64             scissor[i].minx = ctx->Scissor.ScissorArray[i].X;
  65          if (ctx->Scissor.ScissorArray[i].Y > (GLint)scissor[i].miny)
  66             scissor[i].miny = ctx->Scissor.ScissorArray[i].Y;
  67
  68          if (xmax < (GLint) scissor[i].maxx)
  69             scissor[i].maxx = xmax;
  70          if (ymax < (GLint) scissor[i].maxy)
  71             scissor[i].maxy = ymax;
  72
  73          /* check for null space */
  74          if (scissor[i].minx >= scissor[i].maxx || scissor[i].miny >= scissor[i].maxy)
  75             scissor[i].minx = scissor[i].miny = scissor[i].maxx = scissor[i].maxy = 0;
  76       }
  77
  78       /* Now invert Y if needed.
  79        * Gallium drivers use the convention Y=0=top for surfaces.
  80        */
  81       if (st_fb_orientation(fb) == Y_0_TOP) {
  82          miny = fb->Height - scissor[i].maxy;
  83          maxy = fb->Height - scissor[i].miny;
  84          scissor[i].miny = miny;
  85          scissor[i].maxy = maxy;
  86       }
  87
  88       if (memcmp(&scissor[i], &st->state.scissor[i], sizeof(scissor[0])) != 0) {
  89          /* state has changed */
  90          st->state.scissor[i] = scissor[i];  /* struct copy */
  91          changed = true;
  92       }
  93    }
  94    if (changed)
  95       st->pipe->set_scissor_states(st->pipe, 0, ctx->Const.MaxViewports, scissor); /* activate */
  96 }
  97
  98
  99 const struct st_tracked_state st_update_scissor = {
 100    "st_update_scissor",                                 /* name */
 101    {                                                    /* dirty */
 102       (_NEW_SCISSOR | _NEW_BUFFERS),                    /* mesa */
 103       0,                                                /* st */
 104    },
 105    update_scissor                                       /* update */
 106 };