source/libs/cairo/cairo-src/src/cairo-egl-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 typedef struct _cairo_egl_context {
  46     cairo_gl_context_t base;
  47
  48     EGLDisplay display;
  49     EGLContext context;
  50
  51     EGLSurface dummy_surface;
  52
  53     EGLContext previous_context;
  54     EGLSurface previous_surface;
  55 } cairo_egl_context_t;
  56
  57 typedef struct _cairo_egl_surface {
  58     cairo_gl_surface_t base;
  59
  60     EGLSurface egl;
  61 } cairo_egl_surface_t;
  62
  63
  64 static cairo_bool_t
  65 _context_acquisition_changed_egl_state (cairo_egl_context_t *ctx,
  66                                         EGLSurface current_surface)
  67 {
  68     return ctx->previous_context != ctx->context ||
  69            ctx->previous_surface != current_surface;
  70 }
  71
  72 static EGLSurface
  73 _egl_get_current_surface (cairo_egl_context_t *ctx)
  74 {
  75     if (ctx->base.current_target == NULL ||
  76         _cairo_gl_surface_is_texture (ctx->base.current_target)) {
  77         return  ctx->dummy_surface;
  78     }
  79
  80     return ((cairo_egl_surface_t *) ctx->base.current_target)->egl;
  81 }
  82
  83 static void
  84 _egl_query_current_state (cairo_egl_context_t *ctx)
  85 {
  86     ctx->previous_surface = eglGetCurrentSurface (EGL_DRAW);
  87     ctx->previous_context = eglGetCurrentContext ();
  88
  89     /* If any of the values were none, assume they are all none. Not all
  90        drivers seem well behaved when it comes to using these values across
  91        multiple threads. */
  92     if (ctx->previous_surface == EGL_NO_SURFACE ||
  93         ctx->previous_context == EGL_NO_CONTEXT) {
  94         ctx->previous_surface = EGL_NO_SURFACE;
  95         ctx->previous_context = EGL_NO_CONTEXT;
  96     }
  97 }
  98
  99 static void
 100 _egl_acquire (void *abstract_ctx)
 101 {
 102     cairo_egl_context_t *ctx = abstract_ctx;
 103     EGLSurface current_surface = _egl_get_current_surface (ctx);
 104
 105     _egl_query_current_state (ctx);
 106     if (!_context_acquisition_changed_egl_state (ctx, current_surface))
 107         return;
 108
 109     eglMakeCurrent (ctx->display,
 110                     current_surface, current_surface, ctx->context);
 111 }
 112
 113 static void
 114 _egl_release (void *abstract_ctx)
 115 {
 116     cairo_egl_context_t *ctx = abstract_ctx;
 117     if (!ctx->base.thread_aware ||
 118         !_context_acquisition_changed_egl_state (ctx,
 119                                                  _egl_get_current_surface (ctx))) {
 120         return;
 121     }
 122
 123     eglMakeCurrent (ctx->display,
 124                     EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
 125 }
 126
 127 static void
 128 _egl_make_current (void *abstract_ctx,
 129                    cairo_gl_surface_t *abstract_surface)
 130 {
 131     cairo_egl_context_t *ctx = abstract_ctx;
 132     cairo_egl_surface_t *surface = (cairo_egl_surface_t *) abstract_surface;
 133
 134     eglMakeCurrent(ctx->display, surface->egl, surface->egl, ctx->context);
 135 }
 136
 137 static void
 138 _egl_swap_buffers (void *abstract_ctx,
 139                    cairo_gl_surface_t *abstract_surface)
 140 {
 141     cairo_egl_context_t *ctx = abstract_ctx;
 142     cairo_egl_surface_t *surface = (cairo_egl_surface_t *) abstract_surface;
 143
 144     eglSwapBuffers (ctx->display, surface->egl);
 145 }
 146
 147 static void
 148 _egl_destroy (void *abstract_ctx)
 149 {
 150     cairo_egl_context_t *ctx = abstract_ctx;
 151
 152     eglMakeCurrent (ctx->display,
 153                     EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
 154     if (ctx->dummy_surface != EGL_NO_SURFACE)
 155         eglDestroySurface (ctx->display, ctx->dummy_surface);
 156 }
 157
 158 static cairo_bool_t
 159 _egl_make_current_surfaceless(cairo_egl_context_t *ctx)
 160 {
 161     const char *extensions;
 162
 163     extensions = eglQueryString(ctx->display, EGL_EXTENSIONS);
 164     if (strstr(extensions, "EGL_KHR_surfaceless_context") == NULL &&
 165         strstr(extensions, "EGL_KHR_surfaceless_opengl") == NULL)
 166         return FALSE;
 167
 168     if (!eglMakeCurrent(ctx->display,
 169                         EGL_NO_SURFACE, EGL_NO_SURFACE, ctx->context))
 170         return FALSE;
 171
 172     return TRUE;
 173 }
 174
 175 cairo_device_t *
 176 cairo_egl_device_create (EGLDisplay dpy, EGLContext egl)
 177 {
 178     cairo_egl_context_t *ctx;
 179     cairo_status_t status;
 180     int attribs[] = {
 181         EGL_WIDTH, 1,
 182         EGL_HEIGHT, 1,
 183         EGL_NONE,
 184     };
 185     EGLConfig config;
 186     EGLint numConfigs;
 187
 188     ctx = calloc (1, sizeof (cairo_egl_context_t));
 189     if (unlikely (ctx == NULL))
 190         return _cairo_gl_context_create_in_error (CAIRO_STATUS_NO_MEMORY);
 191
 192     ctx->display = dpy;
 193     ctx->context = egl;
 194
 195     ctx->base.acquire = _egl_acquire;
 196     ctx->base.release = _egl_release;
 197     ctx->base.make_current = _egl_make_current;
 198     ctx->base.swap_buffers = _egl_swap_buffers;
 199     ctx->base.destroy = _egl_destroy;
 200
 201     /* We are about the change the current state of EGL, so we should
 202      * query the pre-existing surface now instead of later. */
 203     _egl_query_current_state (ctx);
 204
 205     if (!_egl_make_current_surfaceless (ctx)) {
 206         /* Fall back to dummy surface, meh. */
 207         EGLint config_attribs[] = {
 208             EGL_CONFIG_ID, 0,
 209             EGL_NONE
 210         };
 211
 212         /*
 213          * In order to be able to make an egl context current when using a
 214          * pbuffer surface, that surface must have been created with a config
 215          * that is compatible with the context config. For Mesa, this means
 216          * that the configs must be the same.
 217          */
 218         eglQueryContext (dpy, egl, EGL_CONFIG_ID, &config_attribs[1]);
 219         eglChooseConfig (dpy, config_attribs, &config, 1, &numConfigs);
 220
 221         ctx->dummy_surface = eglCreatePbufferSurface (dpy, config, attribs);
 222         if (ctx->dummy_surface == NULL) {
 223             free (ctx);
 224             return _cairo_gl_context_create_in_error (CAIRO_STATUS_NO_MEMORY);
 225         }
 226
 227         if (!eglMakeCurrent (dpy, ctx->dummy_surface, ctx->dummy_surface, egl)) {
 228             free (ctx);
 229             return _cairo_gl_context_create_in_error (CAIRO_STATUS_NO_MEMORY);
 230         }
 231     }
 232
 233     status = _cairo_gl_dispatch_init (&ctx->base.dispatch, eglGetProcAddress);
 234     if (unlikely (status)) {
 235         free (ctx);
 236         return _cairo_gl_context_create_in_error (status);
 237     }
 238
 239     status = _cairo_gl_context_init (&ctx->base);
 240     if (unlikely (status)) {
 241         if (ctx->dummy_surface != EGL_NO_SURFACE)
 242             eglDestroySurface (dpy, ctx->dummy_surface);
 243         free (ctx);
 244         return _cairo_gl_context_create_in_error (status);
 245     }
 246
 247     /* Tune the default VBO size to reduce overhead on embedded devices.
 248      * This smaller size means that flushing needs to be done more often,
 249      * but it is less demanding of scarce memory on embedded devices.
 250      */
 251     ctx->base.vbo_size = 16*1024;
 252
 253     eglMakeCurrent (dpy, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
 254
 255     return &ctx->base.base;
 256 }
 257
 258 cairo_surface_t *
 259 cairo_gl_surface_create_for_egl (cairo_device_t *device,
 260                                  EGLSurface      egl,
 261                                  int             width,
 262                                  int             height)
 263 {
 264     cairo_egl_surface_t *surface;
 265
 266     if (unlikely (device->status))
 267         return _cairo_surface_create_in_error (device->status);
 268
 269     if (device->backend->type != CAIRO_DEVICE_TYPE_GL)
 270         return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_SURFACE_TYPE_MISMATCH));
 271
 272     if (width <= 0 || height <= 0)
 273         return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_INVALID_SIZE));
 274
 275     surface = calloc (1, sizeof (cairo_egl_surface_t));
 276     if (unlikely (surface == NULL))
 277         return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));
 278
 279     _cairo_gl_surface_init (device, &surface->base,
 280                             CAIRO_CONTENT_COLOR_ALPHA, width, height);
 281     surface->egl = egl;
 282
 283     return &surface->base.base;
 284 }
 285
 286 static cairo_bool_t is_egl_device (cairo_device_t *device)
 287 {
 288     return (device->backend != NULL &&
 289             device->backend->type == CAIRO_DEVICE_TYPE_GL);
 290 }
 291
 292 static cairo_egl_context_t *to_egl_context (cairo_device_t *device)
 293 {
 294     return (cairo_egl_context_t *) device;
 295 }
 296
 297 EGLDisplay
 298 cairo_egl_device_get_display (cairo_device_t *device)
 299 {
 300     if (! is_egl_device (device)) {
 301         _cairo_error_throw (CAIRO_STATUS_DEVICE_TYPE_MISMATCH);
 302         return EGL_NO_DISPLAY;
 303     }
 304
 305     return to_egl_context (device)->display;
 306 }
 307
 308 cairo_public EGLContext
 309 cairo_egl_device_get_context (cairo_device_t *device)
 310 {
 311     if (! is_egl_device (device)) {
 312         _cairo_error_throw (CAIRO_STATUS_DEVICE_TYPE_MISMATCH);
 313         return EGL_NO_CONTEXT;
 314     }
 315
 316     return to_egl_context (device)->context;
 317 }