1/*
2 Copyright (c) 2008-2011 Apple Inc.
3
4 Permission is hereby granted, free of charge, to any person
5 obtaining a copy of this software and associated documentation files
6 (the "Software"), to deal in the Software without restriction,
7 including without limitation the rights to use, copy, modify, merge,
8 publish, distribute, sublicense, and/or sell copies of the Software,
9 and to permit persons to whom the Software is furnished to do so,
10 subject to the following conditions:
11
12 The above copyright notice and this permission notice shall be
13 included in all copies or substantial portions of the Software.
14
15 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18 NONINFRINGEMENT.  IN NO EVENT SHALL THE ABOVE LISTED COPYRIGHT
19 HOLDER(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
20 WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
22 DEALINGS IN THE SOFTWARE.
23
24 Except as contained in this notice, the name(s) of the above
25 copyright holders shall not be used in advertising or otherwise to
26 promote the sale, use or other dealings in this Software without
27 prior written authorization.
28*/
29
30/*
31 * This file works with the glXMakeContextCurrent readable drawable.
32 *
33 * The way it works is by swapping the currentDrawable for the currentReadable
34 * drawable if they are different.
35 */
36#include <stdbool.h>
37#include "glxclient.h"
38#include "apple_glx_context.h"
39#include "apple_xgl_api.h"
40#include "main/glheader.h"
41#include "glapitable.h"
42
43extern struct _glapi_table * __ogl_framework_api;
44
45struct apple_xgl_saved_state
46{
47   bool swapped;
48};
49
50static void
51SetRead(struct apple_xgl_saved_state *saved)
52{
53   struct glx_context *gc = __glXGetCurrentContext();
54
55   /*
56    * By default indicate that the state was not swapped, so that UnsetRead
57    * functions correctly.
58    */
59   saved->swapped = false;
60
61   /*
62    * If the readable drawable isn't the same as the drawable then
63    * the user has requested a readable drawable with glXMakeContextCurrent().
64    * We emulate this behavior by switching the current drawable.
65    */
66   if (None != gc->currentReadable
67       && gc->currentReadable != gc->currentDrawable) {
68      Display *dpy = glXGetCurrentDisplay();
69
70      saved->swapped = true;
71
72      if (apple_glx_make_current_context(dpy, gc->driContext, gc->driContext,
73                                         gc->currentReadable)) {
74         /* An error occurred, so try to restore the old context state. */
75         (void) apple_glx_make_current_context(dpy, gc->driContext, gc->driContext,
76                                               gc->currentDrawable);
77         saved->swapped = false;
78      }
79   }
80}
81
82static void
83UnsetRead(struct apple_xgl_saved_state *saved)
84{
85   if (saved->swapped) {
86      struct glx_context *gc = __glXGetCurrentContext();
87      Display *dpy = glXGetCurrentDisplay();
88
89      if (apple_glx_make_current_context(dpy, gc->driContext, gc->driContext,
90                                         gc->currentDrawable)) {
91         /*
92          * An error occurred restoring the drawable.
93          * It's unclear what to do about that.
94          */
95      }
96   }
97}
98
99void
100__applegl_glReadPixels(GLint x, GLint y, GLsizei width, GLsizei height,
101             GLenum format, GLenum type, void *pixels)
102{
103   struct apple_xgl_saved_state saved;
104
105   SetRead(&saved);
106
107   __ogl_framework_api->ReadPixels(x, y, width, height, format, type, pixels);
108
109   UnsetRead(&saved);
110}
111
112void
113__applegl_glCopyPixels(GLint x, GLint y, GLsizei width, GLsizei height, GLenum type)
114{
115   struct apple_xgl_saved_state saved;
116
117   SetRead(&saved);
118
119   __ogl_framework_api->CopyPixels(x, y, width, height, type);
120
121   UnsetRead(&saved);
122}
123
124void
125__applegl_glCopyColorTable(GLenum target, GLenum internalformat, GLint x, GLint y,
126                 GLsizei width)
127{
128   struct apple_xgl_saved_state saved;
129
130   SetRead(&saved);
131
132   __ogl_framework_api->CopyColorTable(target, internalformat, x, y, width);
133
134   UnsetRead(&saved);
135}
136