/**

  * $Id$

  *

  * 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 <stdlib.h>

 #include <string.h>

 #include "display.h"

 #include <X11/Xlib.h>

 #include <GL/glx.h>

 #include "pvr2/pvr2.h"

 #include "pvr2/glutil.h"

 #include "drivers/video_glx.h"

 #include "drivers/video_gl.h"

 /**

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

  * by calling video_glx_init after initializing itself.

  */

 Display *video_x11_display = NULL;

 Window video_x11_window = 0;

 static int glx_version = 100;

 static XVisualInfo *glx_visual = NULL;

 static GLXFBConfig glx_fbconfig;

 static GLXContext glx_context = NULL;

 static gboolean glx_is_initialized = FALSE;

 static gboolean glx_fbconfig_supported = FALSE;

 static gboolean glx_pbuffer_supported = FALSE;

 static GLuint glx_pbuffer_texture = 0; 

 static void video_glx_swap_buffers( void );

 /* Prototypes for pbuffer support methods */

 static void glx_pbuffer_init( display_driver_t driver );

 static render_buffer_t glx_pbuffer_create_render_buffer( uint32_t width, uint32_t height, GLuint tex_id );

 static void glx_pbuffer_destroy_render_buffer( render_buffer_t buffer );

 static gboolean glx_pbuffer_set_render_target( render_buffer_t buffer );

 static void glx_pbuffer_finish_render( render_buffer_t buffer );

 static void glx_pbuffer_display_render_buffer( render_buffer_t buffer );

 static void glx_pbuffer_load_frame_buffer( frame_buffer_t frame, render_buffer_t buffer );

 static void glx_pbuffer_display_blank( uint32_t colour );

 static gboolean glx_pbuffer_read_render_buffer( unsigned char *target, render_buffer_t buffer, int rowstride, int format );

 /**

  * Test if a specific extension is supported. From opengl.org

  * @param extension extension name to check for

  * @return TRUE if supported, otherwise FALSE.

  */

 gboolean isServerGLXExtensionSupported( Display *display, int screen, 

                                         const char *extension )

 {

     const char *extensions = NULL;

     const char *start;

     char *where, *terminator;

     /* Extension names should not have spaces. */

     where = strchr(extension, ' ');

     if (where || *extension == '\0')

         return 0;

     extensions = glXQueryServerString(display, screen, GLX_EXTENSIONS);

     start = extensions;

     for (;;) {

         where = strstr((const char *) start, extension);

         if (!where)

             break;

         terminator = where + strlen(extension);

         if (where == start || *(where - 1) == ' ')

             if (*terminator == ' ' || *terminator == '\0')

                 return TRUE;

         start = terminator;

     }

     return FALSE;

 }

 gboolean video_glx_init( Display *display, int screen )

 {

     int major, minor;

     int glx_major, glx_minor, glx_error;

     if( glx_is_initialized ) {

         return TRUE;

     }

     Bool result = XQueryExtension( display, "GLX", &glx_major, &glx_minor, &glx_error ) &&

                   glXQueryVersion( display, &major, &minor );

     if( result == False ) {

         ERROR( "GLX not supported on display" );

         return FALSE;

     }

     glx_version = (major*100) + minor;

 #ifdef APPLE_BUILD

     /* fbconfig is broken on at least the 10.5 GLX implementation */

     glx_fbconfig_supported = FALSE;

 #else

     glx_fbconfig_supported = (glx_version >= 103 || 

             isServerGLXExtensionSupported(display, screen,

                     "GLX_SGIX_fbconfig") );

 #endif

     glx_pbuffer_supported = (glx_version >= 103 ||

             isServerGLXExtensionSupported(display, screen,

                     "GLX_SGIX_pbuffer") );

 //    glx_fbconfig_supported = FALSE;

     if( glx_fbconfig_supported ) {

         int nelem;

         int fb_attribs[] = { GLX_DRAWABLE_TYPE, 

                 GLX_PBUFFER_BIT|GLX_WINDOW_BIT, 

                 GLX_RENDER_TYPE, GLX_RGBA_BIT, 

                 GLX_DEPTH_SIZE, 24, 

                 GLX_STENCIL_SIZE, 8, 0 };

         GLXFBConfig *configs = glXChooseFBConfig( display, screen, 

                 fb_attribs, &nelem );

         if( configs == NULL || nelem == 0 ) {

             /* Try a 16-bit depth buffer and see if it helps */

             fb_attribs[5] = 16;

             configs = glXChooseFBConfig( display, screen, fb_attribs, &nelem );

             if( nelem > 0 ) {

                 WARN( "Using a 16-bit depth buffer - expect video glitches" );

             }

         }

         if( configs == NULL || nelem == 0 ) {

             /* Still didn't work. Fallback to 1.2 methods */

             glx_fbconfig_supported = FALSE;

             glx_pbuffer_supported = FALSE;

         } else {

             glx_fbconfig = configs[0];

             glx_visual = glXGetVisualFromFBConfig(display, glx_fbconfig);

             XFree(configs);

         }

     }

     if( !glx_fbconfig_supported ) {

         int attribs[] = { GLX_RGBA, GLX_DEPTH_SIZE, 24, GLX_STENCIL_SIZE, 8, 0 };

         glx_visual = glXChooseVisual( display, screen, attribs );

         if( glx_visual == NULL ) {

             /* Try the 16-bit fallback here too */

             attribs[2] = 16;

             glx_visual = glXChooseVisual( display, screen, attribs );

             if( glx_visual != NULL ) {

                 WARN( "Using a 16-bit depth buffer - expect video glitches" );

             }

         }

     }

     if( glx_visual == NULL ) {

         return FALSE;

     }

     glx_is_initialized = TRUE;

     return TRUE;

 }

 gboolean video_glx_init_context( Display *display, Window window )

 {

     if( glx_fbconfig_supported ) {

         glx_context = glXCreateNewContext( display, glx_fbconfig, 

                 GLX_RGBA_TYPE, NULL, True );

         if( glx_context == NULL ) {

             ERROR( "Unable to create a GLX Context.");

             return FALSE;

         }

         if( glXMakeCurrent( display, window,

                 glx_context ) == False ) {

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

             glXDestroyContext( display, glx_context );

             return FALSE;

         }

     } else {

         glx_context = glXCreateContext( display, glx_visual, None, True );

         if( glx_context == NULL ) {

             ERROR( "Unable to create a GLX Context.");

             return FALSE;

         }

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

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

             glXDestroyContext( display, glx_context );

             return FALSE;

         }

     }

     if( !glXIsDirect(display, glx_context) ) {

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

     }

     video_x11_display = display;

     video_x11_window = window;

     return TRUE;

 }

 gboolean video_glx_init_driver( display_driver_t driver )

 {

     driver->swap_buffers = video_glx_swap_buffers;

     if( gl_fbo_is_supported() ) { // First preference

         gl_fbo_init(driver);

     } else if( glx_pbuffer_supported ) {

         glx_pbuffer_init(driver);

     } else {

         ERROR( "Unable to create render buffers (requires either EXT_framebuffer_object or GLX 1.3+)" );

         video_glx_shutdown();

         return FALSE;

     }

     return TRUE;

 }

 void video_glx_shutdown()

 {

     //    texcache_gl_shutdown();

     glx_is_initialized = FALSE;

     if( glx_context != NULL ) {

         glXDestroyContext( video_x11_display, glx_context );

         glx_context = NULL;

     }

     if( glx_visual != NULL ) {

         XFree(glx_visual);

         glx_visual = NULL;

     }

 }

 XVisualInfo *video_glx_get_visual()

 {

     return glx_visual;

 }

 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;

 }

 static void video_glx_swap_buffers( void )

 {

     glXSwapBuffers( video_x11_display, video_x11_window );

 }

 void video_glx_make_window_current( void )

 {

     glXMakeCurrent( video_x11_display, video_x11_window, glx_context );

 }

 // Pbuffer support

 /**

  * Construct the initial frame buffers and allocate ids for everything.

  * The render handling driver methods are set to the fbo versions.

  */

 static void glx_pbuffer_init( display_driver_t driver ) 

 {

     GLint stencil_bits = 0;

     /* Retrieve the number of stencil bits */

     glGetIntegerv( GL_STENCIL_BITS, &stencil_bits );

     driver->capabilities.stencil_bits = stencil_bits;

     glGenTextures( 1, &glx_pbuffer_texture );

     driver->create_render_buffer = glx_pbuffer_create_render_buffer;

     driver->destroy_render_buffer = glx_pbuffer_destroy_render_buffer;

     driver->set_render_target = glx_pbuffer_set_render_target;

     driver->finish_render = glx_pbuffer_finish_render;

     driver->display_render_buffer = glx_pbuffer_display_render_buffer;

     driver->load_frame_buffer = glx_pbuffer_load_frame_buffer;

     driver->display_blank = glx_pbuffer_display_blank;

     driver->read_render_buffer = glx_pbuffer_read_render_buffer;

 }

 void glx_pbuffer_shutdown()

 {

     glDeleteTextures( 1, &glx_pbuffer_texture );

 }

 static render_buffer_t glx_pbuffer_create_render_buffer( uint32_t width, uint32_t height, GLuint tex_id )

 {

     int attribs[] = { GLX_PBUFFER_WIDTH, width, GLX_PBUFFER_HEIGHT, height,

             GLX_PRESERVED_CONTENTS, True, 0 };

     GLXPbuffer pb = glXCreatePbuffer( video_x11_display, glx_fbconfig, attribs );

     if( pb == (GLXPbuffer)NULL ) {

         ERROR( "Unable to create pbuffer" );

         return NULL;

     }

     render_buffer_t buffer = calloc( sizeof(struct render_buffer), 1 );

     buffer->width = width;

     buffer->height = height;

     buffer->buf_id = pb;

     buffer->tex_id = tex_id;

     return buffer;

 }

 static void glx_pbuffer_destroy_render_buffer( render_buffer_t buffer )

 {

     glXDestroyPbuffer( video_x11_display, (GLXPbuffer)buffer->buf_id );

     buffer->buf_id = 0;

     free( buffer );

 }

 static gboolean glx_pbuffer_set_render_target( render_buffer_t buffer )

 {

     glFinish();

     if( glXMakeContextCurrent( video_x11_display, (GLXPbuffer)buffer->buf_id, (GLXPbuffer)buffer->buf_id, glx_context ) == False ) {

         ERROR( "Make context current (pbuffer) failed!" );

     }

     /* setup the gl context */

     glViewport( 0, 0, buffer->width, buffer->height );

     glDrawBuffer(GL_FRONT);

     return TRUE;

 }

 static void glx_pbuffer_finish_render( render_buffer_t buffer )

 {

     glFinish();

     if( buffer->tex_id != 0 ) {

         // The pbuffer should already be the current context, but just in case...

         glXMakeContextCurrent( video_x11_display, (GLXPbuffer)buffer->buf_id, (GLXPbuffer)buffer->buf_id, glx_context );

         glBindTexture( GL_TEXTURE_RECTANGLE_ARB, buffer->tex_id );

         glCopyTexImage2D(GL_TEXTURE_RECTANGLE_ARB, 0, GL_RGBA, 0, 0, buffer->width, buffer->height, 0 );

     }

 }

 /**

  * Render the texture holding the given buffer to the front window

  * buffer.

  */

 static void glx_pbuffer_display_render_buffer( render_buffer_t buffer )

 {

     glFinish();

     glReadBuffer( GL_FRONT );

     glXMakeContextCurrent( video_x11_display, (GLXPbuffer)buffer->buf_id, (GLXPbuffer)buffer->buf_id, glx_context );

     glBindTexture( GL_TEXTURE_RECTANGLE_ARB, glx_pbuffer_texture );

     glCopyTexImage2D(GL_TEXTURE_RECTANGLE_ARB, 0, GL_RGBA, 0, 0, buffer->width, buffer->height, 0 );

     video_glx_make_window_current();

     gl_texture_window( buffer->width, buffer->height, glx_pbuffer_texture, buffer->inverted );

 }

 static void glx_pbuffer_load_frame_buffer( frame_buffer_t frame, render_buffer_t buffer )

 {

     glFinish();

     glXMakeContextCurrent( video_x11_display, (GLXPbuffer)buffer->buf_id, (GLXPbuffer)buffer->buf_id, glx_context );

     GLenum type = colour_formats[frame->colour_format].type;

     GLenum format = colour_formats[frame->colour_format].format;

     int bpp = colour_formats[frame->colour_format].bpp;

     int rowstride = (frame->rowstride / bpp) - frame->width;

     gl_reset_state();

     glPixelStorei( GL_UNPACK_ROW_LENGTH, rowstride );

     glRasterPos2f(0.375, frame->height-0.375);

     glPixelZoom( 1.0, 1.0 );

     glDrawPixels( frame->width, frame->height, format, type, frame->data );

     glFlush();

 }

 static void glx_pbuffer_display_blank( uint32_t colour )

 {

     glFinish();

     video_glx_make_window_current();

     gl_display_blank( colour );

 }

 static gboolean glx_pbuffer_read_render_buffer( unsigned char *target, render_buffer_t buffer, 

                                                 int rowstride, int format )

 {

     glXMakeCurrent( video_x11_display, (GLXDrawable)buffer->buf_id, glx_context );

     glReadBuffer( GL_FRONT );

     return gl_read_render_buffer( target, buffer, rowstride, format );

 }