/**

  * $Id: video_x11.c,v 1.4 2006-03-16 12:42:28 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 "video.h"

 #include "drivers/video_x11.h"

 /**

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

  * by calling video_x11_set_display after initializing itself.

  */

 Display *video_x11_display = NULL;

 Screen *video_x11_screen = NULL;

 Window video_x11_window = 0;

 /**

  * GLX parameters.

  */

 GLXContext glx_context;

 Window glx_window;

 gboolean glx_open = FALSE;

 void video_x11_set_display( Display *display, Screen *screen, Window window )

 {

     video_x11_display = display;

     video_x11_screen = screen;

     video_x11_window = window;

 }

 gboolean video_glx_create_window( int x, int y, int width, int height )

 {

     int major, minor;

     const char *glxExts, *glxServer;

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

 			   GLX_GREEN_SIZE, 4, 

 			   GLX_BLUE_SIZE, 4,

 			   GLX_ALPHA_SIZE, 4,

 			   GLX_DEPTH_SIZE, 16,

 			   GLX_DOUBLEBUFFER, 

 			   None };

     int screen = XScreenNumberOfScreen(video_x11_screen);

     XSetWindowAttributes win_attrs;

     XVisualInfo *visual;

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

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

 	return FALSE;

     }

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

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

 	return FALSE;

     }

     glxExts = glXQueryExtensionsString( video_x11_display, screen );

     glxServer = glXQueryServerString( video_x11_display, screen, GLX_VENDOR );

     INFO( "GLX version %d.%d, %s. Supported exts: %s", major, minor,

 	  glxServer, glxExts );

     /* Find ourselves a nice visual */

     visual = glXChooseVisual( video_x11_display, 

 			      screen,

 			      visual_attrs );

     if( visual == NULL ) {

 	ERROR( "Unable to obtain a compatible 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" );

 	return FALSE;

     }

     /* Ok, all good so far. Unfortunately the visual we need to use will 

      * almost certainly be different from the one our frame is using. Which 

      * means we have to jump through the following hoops to create a 

      * child window with the appropriate settings.

      */

     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, 

 				x, y, 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" );

 	glXDestroyContext( video_x11_display, glx_context );

 	if( win_attrs.colormap ) 

 	    XFreeColormap( video_x11_display, win_attrs.colormap );

 	return FALSE;

     }

     XMapRaised( video_x11_display, glx_window );

     /* And finally set the window to be the active drawing area */

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

 	/* Ok you have _GOT_ to be kidding me */

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

 	XDestroyWindow( video_x11_display, glx_window );

 	XFreeColormap( video_x11_display, win_attrs.colormap );

 	glXDestroyContext( video_x11_display, glx_context );

 	return FALSE;

     }

     glx_open = TRUE;

     return TRUE;

 }

 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);

 }

 gboolean video_glx_set_render_format( int x, int y, int width, int height )

 {

     if( glx_open )

 	return TRUE;

     return video_glx_create_window( x, y, width, height );

 }

 gboolean video_glx_display_frame( video_buffer_t frame )

 {

     GLenum type, format = GL_RGB;

     switch( frame->colour_format ) {

     case COLFMT_RGB565:

 	type = GL_UNSIGNED_SHORT_5_6_5;

 	break;

     case COLFMT_RGB888:

 	type = GL_UNSIGNED_BYTE;

 	break;

     case COLFMT_ARGB1555:

 	type = GL_UNSIGNED_SHORT_5_5_5_1;

 	break;

     case COLFMT_ARGB8888:

 	format = GL_BGRA;

 	type = GL_UNSIGNED_INT_8_8_8_8_REV;

 	break;

     }

     glDrawBuffer( GL_FRONT );

     glViewport( 0, 0, frame->hres, frame->vres );

     glMatrixMode(GL_PROJECTION);

     glLoadIdentity();

     glOrtho( 0, frame->hres, frame->vres, 0, 0, -65535 );

     glMatrixMode(GL_MODELVIEW);

     glLoadIdentity();

     glRasterPos2i( 0, 0 );

     glPixelZoom( 1.0f, -1.0f );

     glDrawPixels( frame->hres, frame->vres, format, type,

 		  frame->data );

     glFlush();

     return TRUE;

 }

 void video_glx_swap_buffers( void )

 {

     glXSwapBuffers( video_x11_display, glx_window );

 }

 void video_glx_create_pixmap( int width, int height )

 {

 }