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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"

#include 

/* XXX needs hooking into XCloseDisplay() */

typedef struct _cairo_glx_context {

    cairo_gl_context_t base;

    Display *display;

    Window dummy_window;

    GLXContext context;

    GLXDrawable previous_drawable;

    GLXContext previous_context;

    cairo_bool_t has_multithread_makecurrent;

} cairo_glx_context_t;

typedef struct _cairo_glx_surface {

    cairo_gl_surface_t base;

    Window win;

} cairo_glx_surface_t;

static cairo_bool_t

_context_acquisition_changed_glx_state (cairo_glx_context_t *ctx,

					GLXDrawable current_drawable)

{

    return ctx->previous_drawable != current_drawable ||

	   ctx->previous_context != ctx->context;

}

static GLXDrawable

_glx_get_current_drawable (cairo_glx_context_t *ctx)

{

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

	_cairo_gl_surface_is_texture (ctx->base.current_target)) {

	return ctx->dummy_window;

    }

    return ((cairo_glx_surface_t *) ctx->base.current_target)->win;

}

static void

_glx_query_current_state (cairo_glx_context_t * ctx)

{

    ctx->previous_drawable = glXGetCurrentDrawable ();

    ctx->previous_context = glXGetCurrentContext ();

    /* 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_drawable == None ||

	ctx->previous_context == None) {

	ctx->previous_drawable = None;

	ctx->previous_context = None;

    }

}

static void

_glx_acquire (void *abstract_ctx)

{

    cairo_glx_context_t *ctx = abstract_ctx;

    GLXDrawable current_drawable = _glx_get_current_drawable (ctx);

    _glx_query_current_state (ctx);

    if (!_context_acquisition_changed_glx_state (ctx, current_drawable))

	return;

    glXMakeCurrent (ctx->display, current_drawable, ctx->context);

}

static void

_glx_make_current (void *abstract_ctx, cairo_gl_surface_t *abstract_surface)

{

    cairo_glx_context_t *ctx = abstract_ctx;

    cairo_glx_surface_t *surface = (cairo_glx_surface_t *) abstract_surface;

    /* Set the window as the target of our context. */

    glXMakeCurrent (ctx->display, surface->win, ctx->context);

}

static void

_glx_release (void *abstract_ctx)

{

    cairo_glx_context_t *ctx = abstract_ctx;

    if (ctx->has_multithread_makecurrent || !ctx->base.thread_aware ||

	!_context_acquisition_changed_glx_state (ctx,

						_glx_get_current_drawable (ctx))) {

	return;

    }

    glXMakeCurrent (ctx->display, None, None);

}

static void

_glx_swap_buffers (void *abstract_ctx,

		   cairo_gl_surface_t *abstract_surface)

{

    cairo_glx_context_t *ctx = abstract_ctx;

    cairo_glx_surface_t *surface = (cairo_glx_surface_t *) abstract_surface;

    glXSwapBuffers (ctx->display, surface->win);

}

static void

_glx_destroy (void *abstract_ctx)

{

    cairo_glx_context_t *ctx = abstract_ctx;

    if (ctx->dummy_window != None)

	XDestroyWindow (ctx->display, ctx->dummy_window);

    glXMakeCurrent (ctx->display, None, None);

}

static cairo_status_t

_glx_dummy_window (Display *dpy, GLXContext gl_ctx, Window *dummy)

{

    int attr[3] = { GLX_FBCONFIG_ID, 0, None };

    GLXFBConfig *config;

    XVisualInfo *vi;

    Colormap cmap;

    XSetWindowAttributes swa;

    Window win = None;

    int cnt;

    /* Create a dummy window created for the target GLX context that we can

     * use to query the available GL/GLX extensions.

     */

    glXQueryContext (dpy, gl_ctx, GLX_FBCONFIG_ID, &attr[1]);

    cnt = 0;

    config = glXChooseFBConfig (dpy, DefaultScreen (dpy), attr, &cnt);

    if (unlikely (cnt == 0))

	return _cairo_error (CAIRO_STATUS_INVALID_FORMAT);

    vi = glXGetVisualFromFBConfig (dpy, config[0]);

    XFree (config);

    if (unlikely (vi == NULL))

	return _cairo_error (CAIRO_STATUS_INVALID_FORMAT);

    cmap = XCreateColormap (dpy,

			    RootWindow (dpy, vi->screen),

			    vi->visual,

			    AllocNone);

    swa.colormap = cmap;

    swa.border_pixel = 0;

    win = XCreateWindow (dpy, RootWindow (dpy, vi->screen),

			 -1, -1, 1, 1, 0,

			 vi->depth,

			 InputOutput,

			 vi->visual,

			 CWBorderPixel | CWColormap, &swa);

    XFreeColormap (dpy, cmap);

    XFree (vi);

    XFlush (dpy);

    if (unlikely (! glXMakeCurrent (dpy, win, gl_ctx))) {

	XDestroyWindow (dpy, win);

	return _cairo_error (CAIRO_STATUS_NO_MEMORY);

    }

    *dummy = win;

    return CAIRO_STATUS_SUCCESS;

}

cairo_device_t *

cairo_glx_device_create (Display *dpy, GLXContext gl_ctx)

{

    cairo_glx_context_t *ctx;

    cairo_status_t status;

    Window dummy = None;

    const char *glx_extensions;

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

    if (unlikely (ctx == NULL))

	return _cairo_gl_context_create_in_error (CAIRO_STATUS_NO_MEMORY);

    /* glx_dummy_window will call glXMakeCurrent, so we need to

     *  query the current state of the context now. */

    _glx_query_current_state (ctx);

    status = _glx_dummy_window (dpy, gl_ctx, &dummy);

    if (unlikely (status)) {

	free (ctx);

	return _cairo_gl_context_create_in_error (status);

    }

    ctx->display = dpy;

    ctx->dummy_window = dummy;

    ctx->context = gl_ctx;

    ctx->base.acquire = _glx_acquire;

    ctx->base.release = _glx_release;

    ctx->base.make_current = _glx_make_current;

    ctx->base.swap_buffers = _glx_swap_buffers;

    ctx->base.destroy = _glx_destroy;

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

				      (cairo_gl_get_proc_addr_func_t) glXGetProcAddress);

    if (unlikely (status)) {

	free (ctx);

	return _cairo_gl_context_create_in_error (status);

    }

    status = _cairo_gl_context_init (&ctx->base);

    if (unlikely (status)) {

	free (ctx);

	return _cairo_gl_context_create_in_error (status);

    }

    glx_extensions = glXQueryExtensionsString (dpy, DefaultScreen (dpy));

    if (strstr(glx_extensions, "GLX_MESA_multithread_makecurrent")) {

	ctx->has_multithread_makecurrent = TRUE;

    }

    ctx->base.release (ctx);

    return &ctx->base.base;

}

Display *

cairo_glx_device_get_display (cairo_device_t *device)

{

    cairo_glx_context_t *ctx;

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

	_cairo_error_throw (CAIRO_STATUS_DEVICE_TYPE_MISMATCH);

	return NULL;

    }

    ctx = (cairo_glx_context_t *) device;

    return ctx->display;

}

GLXContext

cairo_glx_device_get_context (cairo_device_t *device)

{

    cairo_glx_context_t *ctx;

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

	_cairo_error_throw (CAIRO_STATUS_DEVICE_TYPE_MISMATCH);

	return NULL;

    }

    ctx = (cairo_glx_context_t *) device;

    return ctx->context;

}

cairo_surface_t *

cairo_gl_surface_create_for_window (cairo_device_t	*device,

				    Window		 win,

				    int			 width,

				    int			 height)

{

    cairo_glx_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_glx_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->win = win;

    return &surface->base.base;

}