source/libs/cairo/cairo-src/src/cairo-glx-context.c

   1 /* cairo - a vector graphics library with display and print output
   2  *
   3  * Copyright © 2009 Eric Anholt
   4  * Copyright © 2009 Chris Wilson
   5  * Copyright © 2005 Red Hat, Inc
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it either under the terms of the GNU Lesser General Public
   9  * License version 2.1 as published by the Free Software Foundation
  10  * (the "LGPL") or, at your option, under the terms of the Mozilla
  11  * Public License Version 1.1 (the "MPL"). If you do not alter this
  12  * notice, a recipient may use your version of this file under either
  13  * the MPL or the LGPL.
  14  *
  15  * You should have received a copy of the LGPL along with this library
  16  * in the file COPYING-LGPL-2.1; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
  18  * You should have received a copy of the MPL along with this library
  19  * in the file COPYING-MPL-1.1
  20  *
  21  * The contents of this file are subject to the Mozilla Public License
  22  * Version 1.1 (the "License"); you may not use this file except in
  23  * compliance with the License. You may obtain a copy of the License at
  24  * http://www.mozilla.org/MPL/
  25  *
  26  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
  27  * OF ANY KIND, either express or implied. See the LGPL or the MPL for
  28  * the specific language governing rights and limitations.
  29  *
  30  * The Original Code is the cairo graphics library.
  31  *
  32  * The Initial Developer of the Original Code is Red Hat, Inc.
  33  *
  34  * Contributor(s):
  35  *      Carl Worth <cworth@cworth.org>
  36  *      Chris Wilson <chris@chris-wilson.co.uk>
  37  */
  38
  39 #include "cairoint.h"
  40
  41 #include "cairo-gl-private.h"
  42
  43 #include "cairo-error-private.h"
  44
  45 #include <X11/Xutil.h>
  46
  47 /* XXX needs hooking into XCloseDisplay() */
  48
  49 typedef struct _cairo_glx_context {
  50     cairo_gl_context_t base;
  51
  52     Display *display;
  53     Window dummy_window;
  54     GLXContext context;
  55
  56     GLXDrawable previous_drawable;
  57     GLXContext previous_context;
  58
  59     cairo_bool_t has_multithread_makecurrent;
  60 } cairo_glx_context_t;
  61
  62 typedef struct _cairo_glx_surface {
  63     cairo_gl_surface_t base;
  64
  65     Window win;
  66 } cairo_glx_surface_t;
  67
  68 static cairo_bool_t
  69 _context_acquisition_changed_glx_state (cairo_glx_context_t *ctx,
  70                                         GLXDrawable current_drawable)
  71 {
  72     return ctx->previous_drawable != current_drawable ||
  73            ctx->previous_context != ctx->context;
  74 }
  75
  76 static GLXDrawable
  77 _glx_get_current_drawable (cairo_glx_context_t *ctx)
  78 {
  79     if (ctx->base.current_target == NULL ||
  80         _cairo_gl_surface_is_texture (ctx->base.current_target)) {
  81         return ctx->dummy_window;
  82     }
  83
  84     return ((cairo_glx_surface_t *) ctx->base.current_target)->win;
  85 }
  86
  87 static void
  88 _glx_query_current_state (cairo_glx_context_t * ctx)
  89 {
  90     ctx->previous_drawable = glXGetCurrentDrawable ();
  91     ctx->previous_context = glXGetCurrentContext ();
  92
  93     /* If any of the values were none, assume they are all none. Not all
  94        drivers seem well behaved when it comes to using these values across
  95        multiple threads. */
  96     if (ctx->previous_drawable == None ||
  97         ctx->previous_context == None) {
  98         ctx->previous_drawable = None;
  99         ctx->previous_context = None;
 100     }
 101 }
 102
 103 static void
 104 _glx_acquire (void *abstract_ctx)
 105 {
 106     cairo_glx_context_t *ctx = abstract_ctx;
 107     GLXDrawable current_drawable = _glx_get_current_drawable (ctx);
 108
 109     _glx_query_current_state (ctx);
 110     if (!_context_acquisition_changed_glx_state (ctx, current_drawable))
 111         return;
 112
 113     glXMakeCurrent (ctx->display, current_drawable, ctx->context);
 114 }
 115
 116 static void
 117 _glx_make_current (void *abstract_ctx, cairo_gl_surface_t *abstract_surface)
 118 {
 119     cairo_glx_context_t *ctx = abstract_ctx;
 120     cairo_glx_surface_t *surface = (cairo_glx_surface_t *) abstract_surface;
 121
 122     /* Set the window as the target of our context. */
 123     glXMakeCurrent (ctx->display, surface->win, ctx->context);
 124 }
 125
 126 static void
 127 _glx_release (void *abstract_ctx)
 128 {
 129     cairo_glx_context_t *ctx = abstract_ctx;
 130
 131     if (ctx->has_multithread_makecurrent || !ctx->base.thread_aware ||
 132         !_context_acquisition_changed_glx_state (ctx,
 133                                                 _glx_get_current_drawable (ctx))) {
 134         return;
 135     }
 136
 137     glXMakeCurrent (ctx->display, None, None);
 138 }
 139
 140 static void
 141 _glx_swap_buffers (void *abstract_ctx,
 142                    cairo_gl_surface_t *abstract_surface)
 143 {
 144     cairo_glx_context_t *ctx = abstract_ctx;
 145     cairo_glx_surface_t *surface = (cairo_glx_surface_t *) abstract_surface;
 146
 147     glXSwapBuffers (ctx->display, surface->win);
 148 }
 149
 150 static void
 151 _glx_destroy (void *abstract_ctx)
 152 {
 153     cairo_glx_context_t *ctx = abstract_ctx;
 154
 155     if (ctx->dummy_window != None)
 156         XDestroyWindow (ctx->display, ctx->dummy_window);
 157
 158     glXMakeCurrent (ctx->display, None, None);
 159 }
 160
 161 static cairo_status_t
 162 _glx_dummy_window (Display *dpy, GLXContext gl_ctx, Window *dummy)
 163 {
 164     int attr[3] = { GLX_FBCONFIG_ID, 0, None };
 165     GLXFBConfig *config;
 166     XVisualInfo *vi;
 167     Colormap cmap;
 168     XSetWindowAttributes swa;
 169     Window win = None;
 170     int cnt;
 171
 172     /* Create a dummy window created for the target GLX context that we can
 173      * use to query the available GL/GLX extensions.
 174      */
 175     glXQueryContext (dpy, gl_ctx, GLX_FBCONFIG_ID, &attr[1]);
 176
 177     cnt = 0;
 178     config = glXChooseFBConfig (dpy, DefaultScreen (dpy), attr, &cnt);
 179     if (unlikely (cnt == 0))
 180         return _cairo_error (CAIRO_STATUS_INVALID_FORMAT);
 181
 182     vi = glXGetVisualFromFBConfig (dpy, config[0]);
 183     XFree (config);
 184
 185     if (unlikely (vi == NULL))
 186         return _cairo_error (CAIRO_STATUS_INVALID_FORMAT);
 187
 188     cmap = XCreateColormap (dpy,
 189                             RootWindow (dpy, vi->screen),
 190                             vi->visual,
 191                             AllocNone);
 192     swa.colormap = cmap;
 193     swa.border_pixel = 0;
 194     win = XCreateWindow (dpy, RootWindow (dpy, vi->screen),
 195                          -1, -1, 1, 1, 0,
 196                          vi->depth,
 197                          InputOutput,
 198                          vi->visual,
 199                          CWBorderPixel | CWColormap, &swa);
 200     XFreeColormap (dpy, cmap);
 201     XFree (vi);
 202
 203     XFlush (dpy);
 204     if (unlikely (! glXMakeCurrent (dpy, win, gl_ctx))) {
 205         XDestroyWindow (dpy, win);
 206         return _cairo_error (CAIRO_STATUS_NO_MEMORY);
 207     }
 208
 209     *dummy = win;
 210     return CAIRO_STATUS_SUCCESS;
 211 }
 212
 213 cairo_device_t *
 214 cairo_glx_device_create (Display *dpy, GLXContext gl_ctx)
 215 {
 216     cairo_glx_context_t *ctx;
 217     cairo_status_t status;
 218     Window dummy = None;
 219     const char *glx_extensions;
 220
 221     ctx = calloc (1, sizeof (cairo_glx_context_t));
 222     if (unlikely (ctx == NULL))
 223         return _cairo_gl_context_create_in_error (CAIRO_STATUS_NO_MEMORY);
 224
 225     /* glx_dummy_window will call glXMakeCurrent, so we need to
 226      *  query the current state of the context now. */
 227     _glx_query_current_state (ctx);
 228
 229     status = _glx_dummy_window (dpy, gl_ctx, &dummy);
 230     if (unlikely (status)) {
 231         free (ctx);
 232         return _cairo_gl_context_create_in_error (status);
 233     }
 234
 235     ctx->display = dpy;
 236     ctx->dummy_window = dummy;
 237     ctx->context = gl_ctx;
 238
 239     ctx->base.acquire = _glx_acquire;
 240     ctx->base.release = _glx_release;
 241     ctx->base.make_current = _glx_make_current;
 242     ctx->base.swap_buffers = _glx_swap_buffers;
 243     ctx->base.destroy = _glx_destroy;
 244
 245     status = _cairo_gl_dispatch_init (&ctx->base.dispatch,
 246                                       (cairo_gl_get_proc_addr_func_t) glXGetProcAddress);
 247     if (unlikely (status)) {
 248         free (ctx);
 249         return _cairo_gl_context_create_in_error (status);
 250     }
 251
 252     status = _cairo_gl_context_init (&ctx->base);
 253     if (unlikely (status)) {
 254         free (ctx);
 255         return _cairo_gl_context_create_in_error (status);
 256     }
 257
 258     glx_extensions = glXQueryExtensionsString (dpy, DefaultScreen (dpy));
 259     if (strstr(glx_extensions, "GLX_MESA_multithread_makecurrent")) {
 260         ctx->has_multithread_makecurrent = TRUE;
 261     }
 262
 263     ctx->base.release (ctx);
 264
 265     return &ctx->base.base;
 266 }
 267
 268 Display *
 269 cairo_glx_device_get_display (cairo_device_t *device)
 270 {
 271     cairo_glx_context_t *ctx;
 272
 273     if (device->backend->type != CAIRO_DEVICE_TYPE_GL) {
 274         _cairo_error_throw (CAIRO_STATUS_DEVICE_TYPE_MISMATCH);
 275         return NULL;
 276     }
 277
 278     ctx = (cairo_glx_context_t *) device;
 279
 280     return ctx->display;
 281 }
 282
 283 GLXContext
 284 cairo_glx_device_get_context (cairo_device_t *device)
 285 {
 286     cairo_glx_context_t *ctx;
 287
 288     if (device->backend->type != CAIRO_DEVICE_TYPE_GL) {
 289         _cairo_error_throw (CAIRO_STATUS_DEVICE_TYPE_MISMATCH);
 290         return NULL;
 291     }
 292
 293     ctx = (cairo_glx_context_t *) device;
 294
 295     return ctx->context;
 296 }
 297
 298 cairo_surface_t *
 299 cairo_gl_surface_create_for_window (cairo_device_t      *device,
 300                                     Window               win,
 301                                     int                  width,
 302                                     int                  height)
 303 {
 304     cairo_glx_surface_t *surface;
 305
 306     if (unlikely (device->status))
 307         return _cairo_surface_create_in_error (device->status);
 308
 309     if (device->backend->type != CAIRO_DEVICE_TYPE_GL)
 310         return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_SURFACE_TYPE_MISMATCH));
 311
 312     if (width <= 0 || height <= 0)
 313         return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_INVALID_SIZE));
 314
 315     surface = calloc (1, sizeof (cairo_glx_surface_t));
 316     if (unlikely (surface == NULL))
 317         return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));
 318
 319     _cairo_gl_surface_init (device, &surface->base,
 320                             CAIRO_CONTENT_COLOR_ALPHA, width, height);
 321     surface->win = win;
 322
 323     return &surface->base.base;
 324 }