/**

 * $Id: video_x11.c,v 1.19 2007-10-31 09:11:14 nkeynes Exp $

 *

 * Shared functions for all X11-based display drivers.

 *

 * Copyright (c) 2005 Nathan Keynes.

 *

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

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */

#include <X11/Xlib.h>

#include <GL/glx.h>

#include "dream.h"

#include "drivers/video_x11.h"

#include "drivers/gl_common.h"

extern uint32_t video_width, video_height;

/**

 * General X11 parameters. The front-end driver is expected to set this up

 * by calling video_glx_init after initializing itself.

 */

static Display *video_x11_display = NULL;

static Screen *video_x11_screen = NULL;

static Window video_x11_window = 0;

static gboolean glsl_loaded = FALSE;

/**

 * GLX parameters.

 */

static GLXContext glx_context;

static Window glx_window;

static XSetWindowAttributes win_attrs;

gboolean video_glx_create_window( int width, int height );

gboolean video_glx_init( Display *display, Screen *screen, Window window,

			 int width, int height, display_driver_t driver )

{

    video_x11_display = display;

    video_x11_screen = screen;

    glx_window = video_x11_window = window;

    if( !video_glx_init_context(glx_window) ) {

	return FALSE;

    }

    if( !glXIsDirect(video_x11_display, glx_context) ) {

    	WARN( "Not using direct rendering - this is likely to be slow" );

    }

    if( gl_fbo_is_supported() ) {

	gl_fbo_init(driver);

#ifdef USE_GLSL

	if( glsl_is_supported() ) {

	    glsl_loaded = glsl_load_shaders( glsl_vertex_shader_src, glsl_fragment_shader_src );

	    if( !glsl_loaded ) {

	        WARN( "Shaders failed to load" );

	    }

	} else {

	    WARN( "Shaders not supported" );

	}

#endif

	return TRUE;

    } else {

	/* Pbuffers? */

	ERROR( "Framebuffer objects not supported (required in this version)" );

	video_glx_shutdown();

	return FALSE;

    }

}

/**

 * Create a new window with a custom visual - not used at the moment,

 * but retained for future reference.

 */

gboolean video_x11_create_window( int width, int height )

{

    int visual_attrs[] = { GLX_RGBA, GLX_RED_SIZE, 4, 

			   GLX_GREEN_SIZE, 4, 

			   GLX_BLUE_SIZE, 4,

			   GLX_ALPHA_SIZE, 4,

			   GLX_DEPTH_SIZE, 24,

			   GLX_DOUBLEBUFFER, 

			   None };

    int screen = XScreenNumberOfScreen(video_x11_screen);

    XVisualInfo *visual;

    /* Find ourselves a nice visual */

    visual = glXChooseVisual( video_x11_display, 

			      screen,

			      visual_attrs );

    /* Create a child window with the visual in question */

    win_attrs.event_mask = 0;

    win_attrs.colormap = XCreateColormap( video_x11_display, 

					  RootWindowOfScreen(video_x11_screen),

					  visual->visual, AllocNone );

    glx_window = XCreateWindow( video_x11_display, video_x11_window, 

				0, 0, width, height, 0, visual->depth, 

				InputOutput, visual->visual, 

				CWColormap | CWEventMask, 

				&win_attrs );

    if( glx_window == None ) {

	/* Hrm. Aww, no window? */

	ERROR( "Unable to create GLX window" );

	if( win_attrs.colormap ) 

	    XFreeColormap( video_x11_display, win_attrs.colormap );

	XFree(visual);

	return FALSE;

    }

    XMapRaised( video_x11_display, glx_window );

    XFree(visual);

    return TRUE;

}

gboolean video_glx_init_context( Window window )

{

    XWindowAttributes attr;

    XVisualInfo *visual;

    XVisualInfo query;

    int query_items = 1;

    XGetWindowAttributes(video_x11_display, window, &attr);

    query.visualid = XVisualIDFromVisual(attr.visual);

    visual = XGetVisualInfo(video_x11_display, VisualIDMask, &query, &query_items );

    if( visual == NULL ) {

	ERROR( "Unable to obtain a compatible visual" );

	return FALSE;

    }

    int major, minor;

    if( glXQueryVersion( video_x11_display, &major, &minor ) == False ) {

	ERROR( "X Display lacks the GLX nature" );

	XFree(visual);

	return FALSE;

    }

    if( major < 1 || minor < 2 ) {

	ERROR( "X display supports GLX %d.%d, but we need at least 1.2", major, minor );

	XFree(visual);

	return FALSE;

    }

    /* And a matching gl context */

    glx_context = glXCreateContext( video_x11_display, visual, None, True );

    if( glx_context == NULL ) {

	ERROR( "Unable to obtain a GLX Context. Possibly your system is broken in some small, undefineable way" );

	XFree(visual);

	return FALSE;

    }

    if( glXMakeCurrent( video_x11_display, window, glx_context ) == False ) {

	ERROR( "Unable to prepare GLX context for drawing" );

	glXDestroyContext( video_x11_display, glx_context );

	XFree(visual);

	return FALSE;

    }

    XFree(visual);

    return TRUE;

}

void video_glx_shutdown()

{

    if( glsl_loaded ) {

	glsl_unload_shaders();

    }

    if( glx_window != None ) {

	XDestroyWindow( video_x11_display, glx_window );

	XFreeColormap( video_x11_display, win_attrs.colormap );

	glx_window = None;

    }

    if( glx_context != NULL ) {

	glXDestroyContext( video_x11_display, glx_context );

	glx_context = NULL;

    }

}

int video_glx_load_font( const gchar *font_name )

{

    int lists;

    XFontStruct *font = XLoadQueryFont(video_x11_display, font_name );

    if (font == NULL)

	return -1;

    lists = glGenLists(96);

    glXUseXFont(font->fid, 32, 96, lists);

    XFreeFont(video_x11_display, font);

    return lists;

}

void video_glx_swap_buffers( void )

{

    glXSwapBuffers( video_x11_display, glx_window );

}