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@tungstengraphics.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 */
43static void
44update_scissor( struct st_context *st )
45{
46   struct pipe_scissor_state scissor;
47   const struct gl_context *ctx = st->ctx;
48   const struct gl_framebuffer *fb = ctx->DrawBuffer;
49   GLint miny, maxy;
50
51   scissor.minx = 0;
52   scissor.miny = 0;
53   scissor.maxx = fb->Width;
54   scissor.maxy = fb->Height;
55
56   if (ctx->Scissor.Enabled) {
57      /* need to be careful here with xmax or ymax < 0 */
58      GLint xmax = MAX2(0, ctx->Scissor.X + ctx->Scissor.Width);
59      GLint ymax = MAX2(0, ctx->Scissor.Y + ctx->Scissor.Height);
60
61      if (ctx->Scissor.X > (GLint)scissor.minx)
62         scissor.minx = ctx->Scissor.X;
63      if (ctx->Scissor.Y > (GLint)scissor.miny)
64         scissor.miny = ctx->Scissor.Y;
65
66      if (xmax < (GLint) scissor.maxx)
67         scissor.maxx = xmax;
68      if (ymax < (GLint) scissor.maxy)
69         scissor.maxy = ymax;
70
71      /* check for null space */
72      if (scissor.minx >= scissor.maxx || scissor.miny >= scissor.maxy)
73         scissor.minx = scissor.miny = scissor.maxx = scissor.maxy = 0;
74   }
75
76   /* Now invert Y if needed.
77    * Gallium drivers use the convention Y=0=top for surfaces.
78    */
79   if (st_fb_orientation(fb) == Y_0_TOP) {
80      miny = fb->Height - scissor.maxy;
81      maxy = fb->Height - scissor.miny;
82      scissor.miny = miny;
83      scissor.maxy = maxy;
84   }
85
86   if (memcmp(&scissor, &st->state.scissor, sizeof(scissor)) != 0) {
87      /* state has changed */
88      st->state.scissor = scissor;  /* struct copy */
89      st->pipe->set_scissor_state(st->pipe, &scissor); /* activate */
90   }
91}
92
93
94const struct st_tracked_state st_update_scissor = {
95   "st_update_scissor",					/* name */
96   {							/* dirty */
97      (_NEW_SCISSOR | _NEW_BUFFERS),			/* mesa */
98      0,						/* st */
99   },
100   update_scissor					/* update */
101};
102