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