Import the GLX client side library, formerly from xc/lib/GL/glx. Build it

by adding 'glx/x11' to SRC_DIRS in your build config.

1 files changed, 710 insertions, 0 deletions

diff --git a/src/glx/x11/glxextensions.c b/src/glx/x11/glxextensions.c
new file mode 100644
index 0000000000..8e7afa6b4b
--- /dev/null
+++ b/src/glx/x11/glxextensions.c
@@ -0,0 +1,710 @@
+/*
+ * (C) Copyright IBM Corporation 2002, 2004
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * on the rights to use, copy, modify, merge, publish, distribute, sub
+ * license, and/or sell copies of the Software, and to permit persons to whom
+ * the Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDERS AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+ * USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+/**
+ * \file glxextensions.c
+ *
+ * \author Ian Romanick <idr@us.ibm.com>
+ */
+/* $XFree86: xc/lib/GL/glx/glxextensions.c,v 1.1 2003/09/28 20:15:03 alanh Exp $ */
+
+#include "glxclient.h"
+#include <extutil.h>
+#include <Xext.h>
+#include <string.h>
+#include "glapi.h"
+#include "glxextensions.h"
+#include "simple_list.h"
+
+#define SET_BIT(m,b)   (m[ (b) / 8 ] |=  (1U << ((b) % 8)))
+#define CLR_BIT(m,b)   (m[ (b) / 8 ] &= ~(1U << ((b) % 8)))
+#define IS_SET(m,b)    ((m[ (b) / 8 ] & (1U << ((b) % 8))) != 0)
+#define CONCAT(a,b) a ## b
+#define GLX(n) "GLX_" # n, 4 + sizeof( # n ) - 1, CONCAT(n,_bit)
+#define GL(n)  "GL_" # n,  3 + sizeof( # n ) - 1, GL_ ## n ## _bit
+#define VER(a,b)  a, b
+#define Y  1
+#define N  0
+#define EXT_ENABLED(bit,supported) (IS_SET( supported, bit ))
+
+
+struct extension_info {
+   const char * const name;
+   unsigned   name_len;
+
+   unsigned char  bit;
+
+   /* This is the lowest version of GLX that "requires" this extension.
+    * For example, GLX 1.3 requires SGIX_fbconfig, SGIX_pbuffer, and
+    * SGI_make_current_read.  If the extension is not required by any known
+    * version of GLX, use 0, 0.
+    */
+   unsigned char  version_major;
+   unsigned char  version_minor;
+   unsigned char  client_support;
+   unsigned char  direct_support;
+   unsigned char  client_only;       /** Is the extension client-side only? */
+   unsigned char  direct_only;       /** Is the extension for direct
+				      * contexts only?
+				      */
+};
+
+static const struct extension_info known_glx_extensions[] = {
+   { GLX(ARB_get_proc_address),        VER(1,4), Y, N, Y, N },
+   { GLX(ARB_multisample),             VER(1,4), Y, Y, N, N },
+   { GLX(ARB_render_texture),          VER(0,0), N, N, N, N },
+   { GLX(ATI_pixel_format_float),      VER(0,0), N, N, N, N },
+   { GLX(EXT_import_context),          VER(0,0), Y, Y, N, N },
+   { GLX(EXT_visual_info),             VER(0,0), Y, Y, N, N },
+   { GLX(EXT_visual_rating),           VER(0,0), Y, Y, N, N },
+   { GLX(MESA_agp_offset),             VER(0,0), N, N, N, Y }, /* Deprecated */
+   { GLX(MESA_allocate_memory),        VER(0,0), Y, N, N, Y },
+   { GLX(MESA_copy_sub_buffer),        VER(0,0), N, N, N, N }, /* Deprecated? */
+   { GLX(MESA_pixmap_colormap),        VER(0,0), N, N, N, N }, /* Deprecated */
+   { GLX(MESA_release_buffers),        VER(0,0), N, N, N, N }, /* Deprecated */
+   { GLX(MESA_set_3dfx_mode),          VER(0,0), N, N, N, N }, /* Deprecated */
+   { GLX(MESA_swap_control),           VER(0,0), Y, N, N, Y },
+   { GLX(MESA_swap_frame_usage),       VER(0,0), Y, N, N, Y },
+   { GLX(NV_float_buffer),             VER(0,0), N, N, N, N },
+   { GLX(NV_render_depth_texture),     VER(0,0), N, N, N, N },
+   { GLX(NV_render_texture_rectangle), VER(0,0), N, N, N, N },
+   { GLX(NV_vertex_array_range),       VER(0,0), N, N, N, Y }, /* Deprecated */
+   { GLX(OML_swap_method),             VER(0,0), Y, N, N, N },
+   { GLX(OML_sync_control),            VER(0,0), Y, N, N, Y },
+   { GLX(SGI_cushion),                 VER(0,0), N, N, N, N },
+   { GLX(SGI_make_current_read),       VER(1,3), Y, N, N, N },
+   { GLX(SGI_swap_control),            VER(0,0), Y, N, N, N },
+   { GLX(SGI_video_sync),              VER(0,0), Y, N, N, Y },
+   { GLX(SGIS_blended_overlay),        VER(0,0), N, N, N, N },
+   { GLX(SGIS_color_range),            VER(0,0), N, N, N, N },
+   { GLX(SGIS_multisample),            VER(0,0), Y, Y, N, N },
+   { GLX(SGIX_dm_buffer),              VER(0,0), N, N, N, N },
+   { GLX(SGIX_fbconfig),               VER(1,3), Y, N, N, N },
+   { GLX(SGIX_pbuffer),                VER(1,3), Y, N, N, N },
+   { GLX(SGIX_swap_barrier),           VER(0,0), N, N, N, N },
+   { GLX(SGIX_swap_group),             VER(0,0), N, N, N, N },
+   { GLX(SGIX_video_resize),           VER(0,0), N, N, N, N },
+   { GLX(SGIX_video_source),           VER(0,0), N, N, N, N },
+   { GLX(SGIX_visual_select_group),    VER(0,0), Y, Y, N, N },
+   { GLX(SUN_get_transparent_index),   VER(0,0), N, N, N, N },
+   { NULL }
+};
+
+static const struct extension_info known_gl_extensions[] = {
+   { GL(ARB_depth_texture),              VER(1,4), Y, N, N, N },
+   { GL(ARB_fragment_program),           VER(0,0), N, N, N, N },
+   { GL(ARB_imaging),                    VER(0,0), Y, N, N, N },
+   { GL(ARB_multisample),                VER(1,3), Y, N, N, N },
+   { GL(ARB_multitexture),               VER(1,3), Y, N, N, N },
+   { GL(ARB_occlusion_query),            VER(1,5), N, N, N, N },
+   { GL(ARB_point_parameters),           VER(1,4), Y, N, N, N },
+   { GL(ARB_point_sprite),               VER(0,0), Y, N, N, N },
+   { GL(ARB_shadow),                     VER(1,4), Y, N, N, N },
+   { GL(ARB_shadow_ambient),             VER(0,0), Y, N, N, N },
+   { GL(ARB_texture_border_clamp),       VER(1,3), Y, N, N, N },
+   { GL(ARB_texture_compression),        VER(1,3), N, N, N, N },
+   { GL(ARB_texture_cube_map),           VER(1,3), Y, N, N, N },
+   { GL(ARB_texture_env_add),            VER(1,3), Y, N, N, N },
+   { GL(ARB_texture_env_combine),        VER(1,3), Y, N, N, N },
+   { GL(ARB_texture_env_crossbar),       VER(1,4), Y, N, N, N },
+   { GL(ARB_texture_env_dot3),           VER(1,3), Y, N, N, N },
+   { GL(ARB_texture_mirrored_repeat),    VER(1,4), Y, N, N, N },
+   { GL(ARB_texture_non_power_of_two),   VER(1,5), Y, N, N, N },
+   { GL(ARB_transpose_matrix),           VER(1,3), Y, N, Y, N },
+   { GL(ARB_vertex_buffer_object),       VER(1,5), N, N, N, N },
+   { GL(ARB_window_pos),                 VER(1,4), Y, N, N, N },
+   { GL(EXT_abgr),                       VER(0,0), Y, N, N, N },
+   { GL(EXT_bgra),                       VER(1,2), Y, N, N, N },
+   { GL(EXT_blend_color),                VER(1,4), Y, N, N, N },
+   { GL(EXT_blend_equation_separate),    VER(0,0), N, N, N, N },
+   { GL(EXT_blend_func_separate),        VER(1,4), Y, N, N, N },
+   { GL(EXT_blend_logic_op),             VER(1,4), Y, N, N, N },
+   { GL(EXT_blend_minmax),               VER(1,4), Y, N, N, N },
+   { GL(EXT_blend_subtract),             VER(1,4), Y, N, N, N },
+   { GL(EXT_clip_volume_hint),           VER(0,0), Y, N, N, N },
+   { GL(EXT_compiled_vertex_array),      VER(0,0), N, N, N, N },
+   { GL(EXT_convolution),                VER(0,0), N, N, N, N },
+   { GL(EXT_copy_texture),               VER(1,1), Y, N, N, N },
+   { GL(EXT_cull_vertex),                VER(0,0), N, N, N, N },
+   { GL(EXT_depth_bounds_test),          VER(0,0), N, N, N, N },
+   { GL(EXT_draw_range_elements),        VER(1,2), Y, N, Y, N },
+   { GL(EXT_fog_coord),                  VER(1,4), Y, N, N, N },
+   { GL(EXT_multi_draw_arrays),          VER(1,4), Y, N, Y, N },
+   { GL(EXT_packed_pixels),              VER(1,2), Y, N, N, N },
+   { GL(EXT_paletted_texture),           VER(0,0), Y, N, N, N },
+   { GL(EXT_pixel_buffer_object),        VER(0,0), N, N, N, N },
+   { GL(EXT_point_parameters),           VER(1,4), Y, N, N, N },
+   { GL(EXT_polygon_offset),             VER(1,1), Y, N, N, N },
+   { GL(EXT_rescale_normal),             VER(1,2), Y, N, N, N },
+   { GL(EXT_secondary_color),            VER(1,4), Y, N, N, N },
+   { GL(EXT_separate_specular_color),    VER(1,2), Y, N, N, N },
+   { GL(EXT_shadow_funcs),               VER(1,5), Y, N, N, N },
+   { GL(EXT_shared_texture_palette),     VER(0,0), Y, N, N, N },
+   { GL(EXT_stencil_two_side),           VER(0,0), Y, N, N, N },
+   { GL(EXT_stencil_wrap),               VER(1,4), Y, N, N, N },
+   { GL(EXT_subtexture),                 VER(1,1), Y, N, N, N },
+   { GL(EXT_texture),                    VER(1,1), Y, N, N, N },
+   { GL(EXT_texture3D),                  VER(1,2), Y, N, N, N },
+   { GL(EXT_texture_compression_s3tc),   VER(0,0), N, N, N, N },
+   { GL(EXT_texture_edge_clamp),         VER(1,2), Y, N, N, N },
+   { GL(EXT_texture_env_add),            VER(1,3), Y, N, N, N },
+   { GL(EXT_texture_env_combine),        VER(1,3), Y, N, N, N },
+   { GL(EXT_texture_env_dot3),           VER(0,0), Y, N, N, N },
+   { GL(EXT_texture_filter_anisotropic), VER(0,0), Y, N, N, N },
+   { GL(EXT_texture_lod),                VER(1,2), Y, N, N, N },
+   { GL(EXT_texture_lod_bias),           VER(1,4), Y, N, N, N },
+   { GL(EXT_texture_mirror_clamp),       VER(0,0), Y, N, N, N },
+   { GL(EXT_texture_object),             VER(1,1), Y, N, N, N },
+   { GL(EXT_texture_rectangle),          VER(0,0), Y, N, N, N },
+   { GL(EXT_vertex_array),               VER(0,0), Y, N, N, N },
+   { GL(3DFX_texture_compression_FXT1),  VER(0,0), N, N, N, N },
+   { GL(APPLE_packed_pixels),            VER(1,2), Y, N, N, N },
+   { GL(APPLE_ycbcr_422),                VER(0,0), Y, N, N, N },
+   { GL(ATI_texture_env_combine3),       VER(0,0), Y, N, N, N },
+   { GL(ATI_texture_float),              VER(0,0), Y, N, N, N },
+   { GL(ATI_texture_mirror_once),        VER(0,0), Y, N, N, N },
+   { GL(ATIX_texture_env_combine3),      VER(0,0), Y, N, N, N },
+   { GL(HP_convolution_border_modes),    VER(0,0), Y, N, N, N },
+
+    /* This is currently removed because there seem to be some problems with
+     * it and the software-only indirect rendering path.  At this point, I'm
+     * not sure which side (client or server) has the problem. - idr
+     */
+   { GL(HP_occlusion_test),              VER(0,0), N, N, N, N },
+
+   { GL(IBM_cull_vertex),                VER(0,0), Y, N, N, N },
+   { GL(IBM_pixel_filter_hint),          VER(0,0), Y, N, N, N },
+   { GL(IBM_rasterpos_clip),             VER(0,0), Y, N, N, N },
+   { GL(IBM_texture_clamp_nodraw),       VER(0,0), Y, N, N, N },
+   { GL(IBM_texture_mirrored_repeat),    VER(0,0), Y, N, N, N },
+   { GL(INGR_blend_func_separate),       VER(0,0), Y, N, N, N },
+   { GL(INGR_interlace_read),            VER(0,0), Y, N, N, N },
+   { GL(MESA_pack_invert),               VER(0,0), Y, N, N, N },
+   { GL(MESA_ycbcr_texture),             VER(0,0), Y, N, N, N },
+   { GL(NV_blend_square),                VER(1,4), Y, N, N, N },
+   { GL(NV_copy_depth_to_color),         VER(0,0), Y, N, N, N },
+   { GL(NV_depth_clamp),                 VER(0,0), Y, N, N, N },
+   { GL(NV_fog_distance),                VER(0,0), Y, N, N, N },
+   { GL(NV_light_max_exponent),          VER(0,0), Y, N, N, N },
+   { GL(NV_multisample_filter_hint),     VER(0,0), Y, N, N, N },
+   { GL(NV_point_sprite),                VER(0,0), Y, N, N, N },
+   { GL(NV_texgen_reflection),           VER(0,0), Y, N, N, N },
+   { GL(NV_texture_compression_vtc),     VER(0,0), N, N, N, N },
+   { GL(NV_texture_env_combine4),        VER(0,0), Y, N, N, N },
+   { GL(NV_texture_rectangle),           VER(0,0), Y, N, N, N },
+   { GL(SGIS_generate_mipmap),           VER(1,4), Y, N, N, N },
+   { GL(SGIS_multisample),               VER(0,0), Y, N, N, N },
+   { GL(SGIS_texture_border_clamp),      VER(1,3), Y, N, N, N },
+   { GL(SGIS_texture_edge_clamp),        VER(1,2), Y, N, N, N },
+   { GL(SGIS_texture_lod),               VER(1,2), Y, N, N, N },
+   { GL(SGIX_blend_alpha_minmax),        VER(0,0), Y, N, N, N },
+   { GL(SGIX_clipmap),                   VER(0,0), Y, N, N, N },
+   { GL(SGIX_depth_texture),             VER(0,0), Y, N, N, N },
+   { GL(SGIX_fog_offset),                VER(0,0), Y, N, N, N },
+   { GL(SGIX_shadow),                    VER(0,0), Y, N, N, N },
+   { GL(SGIX_shadow_ambient),            VER(0,0), Y, N, N, N },
+   { GL(SGIX_texture_coordinate_clamp),  VER(0,0), Y, N, N, N },
+   { GL(SGIX_texture_lod_bias),          VER(0,0), Y, N, N, N },
+   { GL(SGIX_texture_range),             VER(0,0), Y, N, N, N },
+   { GL(SGIX_texture_scale_bias),        VER(0,0), Y, N, N, N },
+   { GL(SGIX_vertex_preclip),            VER(0,0), Y, N, N, N },
+   { GL(SGIX_vertex_preclip_hint),       VER(0,0), Y, N, N, N },
+   { GL(SGIX_ycrcb),                     VER(0,0), Y, N, N, N },
+   { GL(SUN_convolution_border_modes),   VER(0,0), Y, N, N, N },
+   { GL(SUN_multi_draw_arrays),          VER(0,0), Y, N, Y, N },
+   { GL(SUN_slice_accum),                VER(0,0), Y, N, N, N },
+   { NULL }
+};
+
+
+#define __GL_EXT_BYTES   ((__NUM_GL_EXTS + 7) / 8)
+
+/* global bit-fields of available extensions and their characteristics */
+static unsigned char client_glx_support[8];
+static unsigned char client_glx_only[8];
+static unsigned char direct_glx_only[8];
+static unsigned char client_gl_support[ __GL_EXT_BYTES ];
+static unsigned char client_gl_only[ __GL_EXT_BYTES ];
+
+/**
+ * Bits representing the set of extensions that are enabled by default in all
+ * direct rendering drivers.
+ */
+static unsigned char direct_glx_support[8];
+
+/**
+ * Highest core GL version that can be supported for indirect rendering.
+ */
+static unsigned gl_major = 0;
+static unsigned gl_minor = 0;
+
+/* client extensions string */
+static const char * __glXGLXClientExtensions = NULL;
+
+static void __glXExtensionsCtr( void );
+static void __glXExtensionsCtrScreen( __GLXscreenConfigs *psc );
+static void __glXProcessServerString( const struct extension_info * ext,
+    const char * server_string, unsigned char * server_support );
+
+/**
+ * Set the state of a GLX extension.
+ *
+ * \param name      Name of the extension.
+ * \param name_len  Length, in characters, of the extension name.
+ * \param state     New state (either enabled or disabled) of the extension.
+ * \param supported Table in which the state of the extension is to be set.
+ */
+static void
+set_glx_extension( const struct extension_info * ext,
+		   const char * name, unsigned name_len, GLboolean state,
+		   unsigned char * supported )
+{
+   unsigned   i;
+
+
+   for ( i = 0 ; ext[i].name != NULL ; i++ ) {
+      if ( (name_len == ext[i].name_len)
+	   && (strncmp( ext[i].name, name, name_len ) == 0) ) {
+	 if ( state ) {
+	    SET_BIT( supported, ext[i].bit );
+	 }
+	 else {
+	    CLR_BIT( supported, ext[i].bit );
+	 }
+
+	 return;
+      }
+   }
+}
+
+
+#define NUL '\0'
+#define SEPARATOR ' '
+
+/**
+ * Convert the server's extension string to a bit-field.
+ * 
+ * \param server_string   GLX extension string from the server.
+ * \param server_support  Bit-field of supported extensions.
+ */
+static void
+__glXProcessServerString( const struct extension_info * ext,
+			  const char * server_string,
+			  unsigned char * server_support )
+{
+   unsigned  base;
+   unsigned  len;
+
+   (void) memset( server_support, 0, sizeof( server_support ) );
+   
+   for ( base = 0 ; server_string[ base ] != NUL ; /* empty */ ) {
+      /* Determine the length of the next extension name.
+       */
+      for ( len = 0
+	    ; (server_string[ base + len ] != SEPARATOR)
+	    && (server_string[ base + len ] != NUL)
+	    ; len++ ) {
+	 /* empty */
+      }
+
+      /* Set the bit for the extension in the server_support table.
+       */
+      set_glx_extension( ext, & server_string[ base ], len, GL_TRUE,
+			 server_support );
+
+ 
+      /* Advance to the next extension string.  This means that we skip
+       * over the previous string and any trialing white-space.
+       */
+      for ( base += len ;
+	    (server_string[ base ] == SEPARATOR)
+	    && (server_string[ base ] != NUL)
+	    ; base++ ) {
+	 /* empty */
+      }
+   }
+}
+
+
+/**
+ * Enable a named GLX extension on a given screen.
+ * Drivers should not call this function directly.  They should instead use
+ * \c glXGetProcAddress to obtain a pointer to the function.
+ *
+ * \param psc   Pointer to GLX per-screen record.
+ * \param name  Name of the extension to enable.
+ *
+ * \sa glXGetProcAddress
+ *
+ * \since Internal API version 20030813.
+ */
+void
+__glXScrEnableExtension( __GLXscreenConfigs *psc, const char * name )
+{
+   __glXExtensionsCtr();
+   __glXExtensionsCtrScreen(psc);
+   set_glx_extension( known_glx_extensions, name, strlen( name ), GL_TRUE,
+		      psc->direct_support );
+}
+
+
+/**
+ * Initialize global extension support tables.
+ */
+
+static void
+__glXExtensionsCtr( void )
+{
+   static const char major_table[32] = { 1, 1, 1, 1, 1, 1, 2, };
+   static const char minor_table[32] = { 0, 1, 2, 3, 4, 5, 0, };
+   unsigned   i;
+   static GLboolean ext_list_first_time = GL_TRUE;
+   unsigned   full_support = ~0;
+
+
+   if ( ext_list_first_time ) {
+      ext_list_first_time = GL_FALSE;
+
+      (void) memset( client_glx_support, 0, sizeof( client_glx_support ) );
+      (void) memset( direct_glx_support, 0, sizeof( direct_glx_support ) );
+      (void) memset( client_glx_only,    0, sizeof( client_glx_only ) );
+      (void) memset( direct_glx_only,    0, sizeof( direct_glx_only ) );
+
+      (void) memset( client_gl_support,  0, sizeof( client_gl_support ) );
+      (void) memset( client_gl_only,     0, sizeof( client_gl_only ) );
+
+      for ( i = 0 ; known_glx_extensions[i].name != NULL ; i++ ) {
+	 const unsigned  bit = known_glx_extensions[i].bit;
+
+	 if ( known_glx_extensions[i].client_support ) {
+	    SET_BIT( client_glx_support, bit );
+	 }
+
+	 if ( known_glx_extensions[i].direct_support ) {
+	    SET_BIT( direct_glx_support, bit );
+	 }
+
+	 if ( known_glx_extensions[i].client_only ) {
+	    SET_BIT( client_glx_only, bit );
+	 }
+
+	 if ( known_glx_extensions[i].direct_only ) {
+	    SET_BIT( direct_glx_only, bit );
+	 }
+      }
+
+      for ( i = 0 ; known_gl_extensions[i].name != NULL ; i++ ) {
+	 const unsigned  bit = known_gl_extensions[i].bit;
+
+	 if ( known_gl_extensions[i].client_support ) {
+	    SET_BIT( client_gl_support, bit );
+	 }
+	 else if ( known_gl_extensions[i].version_major != 0 ) {
+	    /* If an extension that is required for some core GL version is
+	     * not supported, clear the bit for that core GL version as well.
+	     */
+
+	    unsigned ver_bit = (6 * (known_gl_extensions[i].version_major - 1))
+	      + (known_gl_extensions[i].version_minor);
+
+	    full_support &= ~(1U << ver_bit);
+	 }
+
+	 if ( known_gl_extensions[i].client_only ) {
+	    SET_BIT( client_gl_only, bit );
+	 }
+      }
+      
+      /* Determine the lowest unsupported core GL version.  The version before
+       * that is, therefore, the highest supported core GL version.
+       */
+      for ( i = 0 ; (full_support & (1 << i)) != 0 ; i++ )
+	 /* empty */ ;
+
+      i--;
+      gl_major = major_table[i];
+      gl_minor = minor_table[i];
+#if 0
+      fprintf( stderr, "[%s:%u] Maximum client library version: %u.%u\n",
+	       __func__, __LINE__, gl_major, gl_minor );
+#endif
+   }
+}
+
+
+/**
+ * Make sure that per-screen direct-support table is initialized.
+ *
+ * \param psc  Pointer to GLX per-screen record.
+ */
+
+static void
+__glXExtensionsCtrScreen( __GLXscreenConfigs *psc )
+{
+    if (psc->ext_list_first_time) {
+	psc->ext_list_first_time = GL_FALSE;
+	(void) memcpy( psc->direct_support, direct_glx_support,
+		       sizeof( direct_glx_support ) );
+    }
+}
+
+
+/**
+ * Check if a certain extension is enabled on a given screen.
+ *
+ * \param psc  Pointer to GLX per-screen record.
+ * \param bit  Bit index in the direct-support table.
+ * \returns If the extension bit is enabled for the screen, \c GL_TRUE is
+ *          returned.  If the extension bit is not enabled or if \c psc is
+ *          \c NULL, then \c GL_FALSE is returned.
+ */
+GLboolean
+__glXExtensionBitIsEnabled( __GLXscreenConfigs *psc, unsigned bit )
+{
+   GLboolean enabled = GL_FALSE;
+
+   if ( psc != NULL ) {
+      __glXExtensionsCtr();
+      __glXExtensionsCtrScreen( psc );
+      enabled = EXT_ENABLED( bit, psc->direct_support );
+   }
+
+   return enabled;
+}
+
+
+/**
+ * Convert a bit-field to a string of supported extensions.
+ */
+static char *
+__glXGetStringFromTable( const struct extension_info * ext,
+			 const unsigned char * supported )
+{
+   unsigned   i;
+   unsigned   ext_str_len;
+   char * ext_str;
+   char * point;
+
+
+   ext_str_len = 0;
+   for ( i = 0 ; ext[i].name != NULL ; i++ ) {
+      if ( EXT_ENABLED( ext[i].bit, supported ) ) {
+	 ext_str_len += ext[i].name_len + 1;
+      }
+   }
+
+   ext_str = Xmalloc( ext_str_len + 1 );
+   if ( ext_str != NULL ) {
+      point = ext_str;
+
+      for ( i = 0 ; ext[i].name != NULL ; i++ ) {
+	 if ( EXT_ENABLED( ext[i].bit, supported ) ) {
+	    (void) memcpy( point, ext[i].name, ext[i].name_len );
+	    point += ext[i].name_len;
+
+	    *point = ' ';
+	    point++;
+	 }
+      }
+
+      *point = '\0';
+   }
+
+   return ext_str;
+}
+
+
+/**
+ * Get the string of client library supported extensions.
+ */
+const char *
+__glXGetClientExtensions( void )
+{
+   if ( __glXGLXClientExtensions == NULL ) {
+      __glXExtensionsCtr();
+      __glXGLXClientExtensions = __glXGetStringFromTable( known_glx_extensions,
+							  client_glx_support );
+   }
+
+   return __glXGLXClientExtensions;
+}
+
+
+/**
+ * Calculate the list of application usable extensions.  The resulting
+ * string is stored in \c psc->effectiveGLXexts.
+ * 
+ * \param psc                        Pointer to GLX per-screen record.
+ * \param display_is_direct_capable  True if the display is capable of
+ *                                   direct rendering.
+ * \param minor_version              GLX minor version from the server.
+ */
+
+void
+__glXCalculateUsableExtensions( __GLXscreenConfigs *psc,
+				GLboolean display_is_direct_capable,
+				int minor_version )
+{
+   unsigned char server_support[8];
+   unsigned char usable[8];
+   unsigned      i;
+
+   __glXExtensionsCtr();
+   __glXExtensionsCtrScreen( psc );
+   __glXProcessServerString( known_glx_extensions,
+			     psc->serverGLXexts, server_support );
+
+
+   /* This is a hack.  Some servers support GLX 1.3 but don't export
+    * all of the extensions implied by GLX 1.3.  If the server claims
+    * support for GLX 1.3, enable support for the extensions that can be
+    * "emulated" as well.
+    */
+
+   if ( minor_version >= 3 ) {
+      SET_BIT( server_support, EXT_visual_info_bit );
+      SET_BIT( server_support, EXT_visual_rating_bit );
+      SET_BIT( server_support, SGI_make_current_read_bit );
+      SET_BIT( server_support, SGIX_fbconfig_bit );
+      SET_BIT( server_support, SGIX_pbuffer_bit );
+       
+      /* This one is a little iffy.  GLX 1.3 doesn't incorporate all of this
+       * extension.  However, the only part that is not strictly client-side
+       * is shared.  That's the glXQueryContext / glXQueryContextInfoEXT
+       * function.
+       */
+
+      SET_BIT( server_support, EXT_import_context_bit );
+   }
+
+
+   /* An extension is supported if the client-side (i.e., libGL) supports
+    * it and the "server" supports it.  In this case that means that either
+    * the true server supports it or it is only for direct-rendering and
+    * the direct rendering driver supports it.
+    * 
+    * If the display is not capable of direct rendering, then the extension
+    * is enabled if and only if the client-side library and the server
+    * support it.
+    */
+
+   if ( display_is_direct_capable ) {
+      for ( i = 0 ; i < 8 ; i++ ) {
+	 usable[i] = (client_glx_support[i] & client_glx_only[i])
+	     | (client_glx_support[i] & psc->direct_support[i] & server_support[i])
+	     | (client_glx_support[i] & psc->direct_support[i] & direct_glx_only[i]);
+      }
+   }
+   else {
+      for ( i = 0 ; i < 8 ; i++ ) {
+	 usable[i] = (client_glx_support[i] & client_glx_only[i])
+	     | (client_glx_support[i] & server_support[i]);
+      }
+   }
+
+   psc->effectiveGLXexts = __glXGetStringFromTable( known_glx_extensions,
+						    usable );
+}
+
+
+/**
+ * Calculate the list of application usable extensions.  The resulting
+ * string is stored in \c gc->extensions.
+ * 
+ * \param gc             Pointer to GLX context.
+ * \param server_string  Extension string from the server.
+ * \param major_version  GL major version from the server.
+ * \param minor_version  GL minor version from the server.
+ */
+
+void
+__glXCalculateUsableGLExtensions( __GLXcontext * gc,
+				  const char * server_string,
+				  int major_version, int minor_version )
+{
+   unsigned char server_support[ __GL_EXT_BYTES ];
+   unsigned char usable[ __GL_EXT_BYTES ];
+   unsigned      i;
+
+
+   __glXExtensionsCtr();
+
+   (void) memset( server_support, 0, sizeof( server_support ) );
+   __glXProcessServerString( known_gl_extensions, server_string,
+			     server_support );
+
+
+   /* Handle lazy servers that don't export all the extensions strings that
+    * are part of the GL core version that they support.
+    */
+
+   for ( i = 0 ; i < __GL_EXT_BYTES ; i++ ) {
+      if ( (known_gl_extensions[i].version_major != 0)
+	   && ((major_version > known_gl_extensions[i].version_major)
+	       || ((major_version == known_gl_extensions[i].version_major)
+		   && (minor_version >= known_gl_extensions[i].version_minor))) ) {
+	 SET_BIT( server_support, known_gl_extensions[i].bit );
+      }
+   }
+
+
+   /* An extension is supported if the client-side (i.e., libGL) supports
+    * it and the server supports it or the client-side library supports it
+    * and it only needs client-side support.
+    */
+
+   for ( i = 0 ; i < __GL_EXT_BYTES ; i++ ) {
+      usable[i] = (client_gl_support[i] & client_gl_only[i])
+	| (client_gl_support[i] & server_support[i]);
+   }
+
+   gc->extensions = (unsigned char *) 
+     __glXGetStringFromTable( known_gl_extensions, usable );
+}
+
+
+/**
+ * Calculates the maximum core GL version that can be supported for indirect
+ * rendering.
+ */
+void
+__glXGetGLVersion( int * major_version, int * minor_version )
+{		   
+    __glXExtensionsCtr();
+    *major_version = gl_major;
+    *minor_version = gl_minor;
+}
+
+
+/**
+ * Get a string representing the set of extensions supported by the client
+ * library.  This is currently only used to send the list of extensions
+ * supported by the client to the server.
+ */
+char *
+__glXGetClientGLExtensionString( void )
+{
+    __glXExtensionsCtr();
+    return __glXGetStringFromTable( known_gl_extensions, client_gl_support );
+}