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/* cairo - a vector graphics library with display and print output

 *

 * Copyright © 2009 Eric Anholt

 * Copyright © 2009 Chris Wilson

 * Copyright © 2005 Red Hat, Inc

 *

 * This library is free software; you can redistribute it and/or

 * modify it either under the terms of the GNU Lesser General Public

 * License version 2.1 as published by the Free Software Foundation

 * (the "LGPL") or, at your option, under the terms of the Mozilla

 * Public License Version 1.1 (the "MPL"). If you do not alter this

 * notice, a recipient may use your version of this file under either

 * the MPL or the LGPL.

 *

 * You should have received a copy of the LGPL along with this library

 * in the file COPYING-LGPL-2.1; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA

 * You should have received a copy of the MPL along with this library

 * in the file COPYING-MPL-1.1

 *

 * The contents of this file are subject to the Mozilla Public License

 * Version 1.1 (the "License"); you may not use this file except in

 * compliance with the License. You may obtain a copy of the License at

 * http://www.mozilla.org/MPL/

 *

 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY

 * OF ANY KIND, either express or implied. See the LGPL or the MPL for

 * the specific language governing rights and limitations.

 *

 * The Original Code is the cairo graphics library.

 *

 * The Initial Developer of the Original Code is Red Hat, Inc.

 *

 * Contributor(s):

 *	Carl Worth 

 *	Chris Wilson 

 */

#include "cairoint.h"

#include "cairo-gl-private.h"

#include "cairo-error-private.h"

typedef struct _cairo_egl_context {

    cairo_gl_context_t base;

    EGLDisplay display;

    EGLContext context;

    EGLSurface dummy_surface;

    EGLContext previous_context;

    EGLSurface previous_surface;

} cairo_egl_context_t;

typedef struct _cairo_egl_surface {

    cairo_gl_surface_t base;

    EGLSurface egl;

} cairo_egl_surface_t;

static cairo_bool_t

_context_acquisition_changed_egl_state (cairo_egl_context_t *ctx,

					EGLSurface current_surface)

{

    return ctx->previous_context != ctx->context ||

	   ctx->previous_surface != current_surface;

}

static EGLSurface

_egl_get_current_surface (cairo_egl_context_t *ctx)

{

    if (ctx->base.current_target == NULL ||

        _cairo_gl_surface_is_texture (ctx->base.current_target)) {

	return  ctx->dummy_surface;

    }

    return ((cairo_egl_surface_t *) ctx->base.current_target)->egl;

}

static void

_egl_query_current_state (cairo_egl_context_t *ctx)

{

    ctx->previous_surface = eglGetCurrentSurface (EGL_DRAW);

    ctx->previous_context = eglGetCurrentContext ();

    /* If any of the values were none, assume they are all none. Not all

       drivers seem well behaved when it comes to using these values across

       multiple threads. */

    if (ctx->previous_surface == EGL_NO_SURFACE ||

	ctx->previous_context == EGL_NO_CONTEXT) {

	ctx->previous_surface = EGL_NO_SURFACE;

	ctx->previous_context = EGL_NO_CONTEXT;

    }

}

static void

_egl_acquire (void *abstract_ctx)

{

    cairo_egl_context_t *ctx = abstract_ctx;

    EGLSurface current_surface = _egl_get_current_surface (ctx);

    _egl_query_current_state (ctx);

    if (!_context_acquisition_changed_egl_state (ctx, current_surface))

	return;

    eglMakeCurrent (ctx->display,

		    current_surface, current_surface, ctx->context);

}

static void

_egl_release (void *abstract_ctx)

{

    cairo_egl_context_t *ctx = abstract_ctx;

    if (!ctx->base.thread_aware ||

	!_context_acquisition_changed_egl_state (ctx,

						 _egl_get_current_surface (ctx))) {

	return;

    }

    eglMakeCurrent (ctx->display,

		    EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);

}

static void

_egl_make_current (void *abstract_ctx,

	           cairo_gl_surface_t *abstract_surface)

{

    cairo_egl_context_t *ctx = abstract_ctx;

    cairo_egl_surface_t *surface = (cairo_egl_surface_t *) abstract_surface;

    eglMakeCurrent(ctx->display, surface->egl, surface->egl, ctx->context);

}

static void

_egl_swap_buffers (void *abstract_ctx,

		   cairo_gl_surface_t *abstract_surface)

{

    cairo_egl_context_t *ctx = abstract_ctx;

    cairo_egl_surface_t *surface = (cairo_egl_surface_t *) abstract_surface;

    eglSwapBuffers (ctx->display, surface->egl);

}

static void

_egl_destroy (void *abstract_ctx)

{

    cairo_egl_context_t *ctx = abstract_ctx;

    eglMakeCurrent (ctx->display,

		    EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);

    if (ctx->dummy_surface != EGL_NO_SURFACE)

        eglDestroySurface (ctx->display, ctx->dummy_surface);

}

static cairo_bool_t

_egl_make_current_surfaceless(cairo_egl_context_t *ctx)

{

    const char *extensions;

    extensions = eglQueryString(ctx->display, EGL_EXTENSIONS);

    if (strstr(extensions, "EGL_KHR_surfaceless_context") == NULL &&

	strstr(extensions, "EGL_KHR_surfaceless_opengl") == NULL)

	return FALSE;

    if (!eglMakeCurrent(ctx->display,

			EGL_NO_SURFACE, EGL_NO_SURFACE, ctx->context))

	return FALSE;

    return TRUE;

}

cairo_device_t *

cairo_egl_device_create (EGLDisplay dpy, EGLContext egl)

{

    cairo_egl_context_t *ctx;

    cairo_status_t status;

    int attribs[] = {

	EGL_WIDTH, 1,

	EGL_HEIGHT, 1,

	EGL_NONE,

    };

    EGLConfig config;

    EGLint numConfigs;

    ctx = calloc (1, sizeof (cairo_egl_context_t));

    if (unlikely (ctx == NULL))

	return _cairo_gl_context_create_in_error (CAIRO_STATUS_NO_MEMORY);

    ctx->display = dpy;

    ctx->context = egl;

    ctx->base.acquire = _egl_acquire;

    ctx->base.release = _egl_release;

    ctx->base.make_current = _egl_make_current;

    ctx->base.swap_buffers = _egl_swap_buffers;

    ctx->base.destroy = _egl_destroy;

    /* We are about the change the current state of EGL, so we should

     * query the pre-existing surface now instead of later. */

    _egl_query_current_state (ctx);

    if (!_egl_make_current_surfaceless (ctx)) {

	/* Fall back to dummy surface, meh. */

	EGLint config_attribs[] = {

	    EGL_CONFIG_ID, 0,

	    EGL_NONE

	};

	/*

	 * In order to be able to make an egl context current when using a

	 * pbuffer surface, that surface must have been created with a config

	 * that is compatible with the context config. For Mesa, this means

	 * that the configs must be the same.

	 */

	eglQueryContext (dpy, egl, EGL_CONFIG_ID, &config_attribs[1]);

	eglChooseConfig (dpy, config_attribs, &config, 1, &numConfigs);

	ctx->dummy_surface = eglCreatePbufferSurface (dpy, config, attribs);

	if (ctx->dummy_surface == NULL) {

	    free (ctx);

	    return _cairo_gl_context_create_in_error (CAIRO_STATUS_NO_MEMORY);

	}

	if (!eglMakeCurrent (dpy, ctx->dummy_surface, ctx->dummy_surface, egl)) {

	    free (ctx);

	    return _cairo_gl_context_create_in_error (CAIRO_STATUS_NO_MEMORY);

	}

    }

    status = _cairo_gl_dispatch_init (&ctx->base.dispatch, eglGetProcAddress);

    if (unlikely (status)) {

	free (ctx);

	return _cairo_gl_context_create_in_error (status);

    }

    status = _cairo_gl_context_init (&ctx->base);

    if (unlikely (status)) {

	if (ctx->dummy_surface != EGL_NO_SURFACE)

	    eglDestroySurface (dpy, ctx->dummy_surface);

	free (ctx);

	return _cairo_gl_context_create_in_error (status);

    }

    eglMakeCurrent (dpy, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);

    return &ctx->base.base;

}

cairo_surface_t *

cairo_gl_surface_create_for_egl (cairo_device_t	*device,

				 EGLSurface	 egl,

				 int		 width,

				 int		 height)

{

    cairo_egl_surface_t *surface;

    if (unlikely (device->status))

	return _cairo_surface_create_in_error (device->status);

    if (device->backend->type != CAIRO_DEVICE_TYPE_GL)

	return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_SURFACE_TYPE_MISMATCH));

    if (width <= 0 || height <= 0)

        return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_INVALID_SIZE));

    surface = calloc (1, sizeof (cairo_egl_surface_t));

    if (unlikely (surface == NULL))

	return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));

    _cairo_gl_surface_init (device, &surface->base,

			    CAIRO_CONTENT_COLOR_ALPHA, width, height);

    surface->egl = egl;

    return &surface->base.base;

}

static cairo_bool_t is_egl_device (cairo_device_t *device)

{

    return (device->backend != NULL &&

	    device->backend->type == CAIRO_DEVICE_TYPE_GL);

}

static cairo_egl_context_t *to_egl_context (cairo_device_t *device)

{

    return (cairo_egl_context_t *) device;

}

EGLDisplay

cairo_egl_device_get_display (cairo_device_t *device)

{

    if (! is_egl_device (device)) {

	_cairo_error_throw (CAIRO_STATUS_DEVICE_TYPE_MISMATCH);

	return EGL_NO_DISPLAY;

    }

    return to_egl_context (device)->display;

}

cairo_public EGLContext

cairo_egl_device_get_context (cairo_device_t *device)

{

    if (! is_egl_device (device)) {

	_cairo_error_throw (CAIRO_STATUS_DEVICE_TYPE_MISMATCH);

	return EGL_NO_CONTEXT;

    }

    return to_egl_context (device)->context;

}