/**

  * $Id: video_x11.c,v 1.20 2007-10-31 12:05:23 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_context( Window window );

 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 );

 }