src/glx/apple/apple_xgl_api_read.c

   1 /*
   2  Copyright (c) 2008, 2009 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
  41 extern struct apple_xgl_api __ogl_framework_api;
  42
  43 struct apple_xgl_saved_state
  44 {
  45    bool swapped;
  46 };
  47
  48 static void
  49 SetRead(struct apple_xgl_saved_state *saved)
  50 {
  51    struct glx_context *gc = __glXGetCurrentContext();
  52
  53    /*
  54     * By default indicate that the state was not swapped, so that UnsetRead
  55     * functions correctly.
  56     */
  57    saved->swapped = false;
  58
  59    /*
  60     * If the readable drawable isn't the same as the drawable then
  61     * the user has requested a readable drawable with glXMakeContextCurrent().
  62     * We emulate this behavior by switching the current drawable.
  63     */
  64    if (None != gc->currentReadable
  65        && gc->currentReadable != gc->currentDrawable) {
  66       Display *dpy = glXGetCurrentDisplay();
  67
  68       saved->swapped = true;
  69
  70       if (apple_glx_make_current_context(dpy, gc->driContext, gc->driContext,
  71                                          gc->currentReadable)) {
  72          /* An error occurred, so try to restore the old context state. */
  73          (void) apple_glx_make_current_context(dpy, gc->driContext, gc->driContext,
  74                                                gc->currentDrawable);
  75          saved->swapped = false;
  76       }
  77    }
  78 }
  79
  80 static void
  81 UnsetRead(struct apple_xgl_saved_state *saved)
  82 {
  83    if (saved->swapped) {
  84       struct glx_context *gc = __glXGetCurrentContext();
  85       Display *dpy = glXGetCurrentDisplay();
  86
  87       if (apple_glx_make_current_context(dpy, gc->driContext, gc->driContext,
  88                                          gc->currentDrawable)) {
  89          /*
  90           * An error occurred restoring the drawable.
  91           * It's unclear what to do about that.
  92           */
  93       }
  94    }
  95 }
  96
  97 void
  98 glReadPixels(GLint x, GLint y, GLsizei width, GLsizei height,
  99              GLenum format, GLenum type, void *pixels)
 100 {
 101    struct apple_xgl_saved_state saved;
 102
 103    SetRead(&saved);
 104
 105    __ogl_framework_api.ReadPixels(x, y, width, height, format, type, pixels);
 106
 107    UnsetRead(&saved);
 108 }
 109
 110 void
 111 glCopyPixels(GLint x, GLint y, GLsizei width, GLsizei height, GLenum type)
 112 {
 113    struct apple_xgl_saved_state saved;
 114
 115    SetRead(&saved);
 116
 117    __ogl_framework_api.CopyPixels(x, y, width, height, type);
 118
 119    UnsetRead(&saved);
 120 }
 121
 122 void
 123 glCopyColorTable(GLenum target, GLenum internalformat, GLint x, GLint y,
 124                  GLsizei width)
 125 {
 126    struct apple_xgl_saved_state saved;
 127
 128    SetRead(&saved);
 129
 130    __ogl_framework_api.CopyColorTable(target, internalformat, x, y, width);
 131
 132    UnsetRead(&saved);
 133 }