I am attempting to use the ARB vertex program and ARB fragment program extensions in SDL (ARB_vertex_program and ARB_fragment_program). A quick look at glxinfo confirms my card (geforce fx 5200) supports these extensions : jurquhart@genty jurquhart $ glxinfo |grep _program, GL_ARB_depth_texture, GL_ARB_fragment_program, GL_ARB_imaging, GL_ARB_vertex_buffer_object, GL_ARB_vertex_program, GL_ARB_window_pos, GL_NV_float_buffer, GL_NV_fog_distance, GL_NV_fragment_program, GL_NV_vertex_array_range, GL_NV_vertex_array_range2, GL_NV_vertex_program, On an additional note, i am using the latest unstable gentoo. This does not appear to happen on non-gentoo systems, so i suspect there is a problem with gentoo somewhere. Reproducible: Always Steps to Reproduce: 1. Download the test program 2. Run test_run.sh 3. Note results Actual Results: Using the extension with GLUT works. Using the extension with SDL fails. It cannot get the proc address! (via SDL_GL_GetProcAddress()) See the "my_output" file in the attatched test program archive for the output i get. Expected Results: SDL_GL_GetProcAddress() should have returned the ARB shader extension functions. output from "glxinfo |grep _program," : GL_ARB_depth_texture, GL_ARB_fragment_program, GL_ARB_imaging, GL_ARB_vertex_buffer_object, GL_ARB_vertex_program, GL_ARB_window_pos, GL_NV_float_buffer, GL_NV_fog_distance, GL_NV_fragment_program, GL_NV_vertex_array_range, GL_NV_vertex_array_range2, GL_NV_vertex_program, 'emerge info' : Portage 2.0.50-r1 (default-x86-2004.0, gcc-3.3.3, glibc-2.3.3_pre20040207-r0, 2.6.5-rc2) ================================================================= System uname: 2.6.5-rc2 i686 AMD Athlon(tm) XP 2000+ Gentoo Base System version 1.4.3.13p1 Autoconf: sys-devel/autoconf-2.59-r3 Automake: sys-devel/automake-1.8.3 ACCEPT_KEYWORDS="x86 ~x86" AUTOCLEAN="yes" CFLAGS="-march=athlon-xp -O3 -pipe -msse -ffast-math -fomit-frame-pointer -mmmx -m3dnow -mfpmath=sse -Wall -fexpensive-optimizations -funroll-loops -frerun-loop-opt -frerun-cse-after-loop -falign-functions=16 -falign-labels=1 -foptimize-sibling-calls -fstrength-reduce -fprefetch-loop-arrays" CHOST="i686-pc-linux-gnu" COMPILER="gcc3" CONFIG_PROTECT="/etc /usr/X11R6/lib/X11/xkb /usr/kde/2/share/config /usr/kde/3.2/share/config /usr/kde/3/share/config /usr/lib/mozilla/defaults/pref /usr/share/config /var/qmail/control" CONFIG_PROTECT_MASK="/etc/gconf /etc/terminfo /etc/env.d" CXXFLAGS="-march=athlon-xp -O3 -pipe -msse -ffast-math -fomit-frame-pointer -mmmx -m3dnow -mfpmath=sse -Wall -fexpensive-optimizations -funroll-loops -frerun-loop-opt -frerun-cse-after-loop -falign-functions=16 -falign-labels=1 -foptimize-sibling-calls -fstrength-reduce -fprefetch-loop-arrays" DISTDIR="/usr/portage/distfiles" FEATURES="autoaddcvs buildpkg ccache distcc sandbox" GENTOO_MIRRORS="http://212.219.247.15/sites/www.ibiblio.org/gentoo/ http://212.219.247.10/sites/www.ibiblio.org/gentoo/ http://212.219.247.14/sites/www.ibiblio.org/gentoo/ http://212.219.247.12/sites/www.ibiblio.org/gentoo/" MAKEOPTS="-j2" PKGDIR="/usr/portage/packages" PORTAGE_TMPDIR="/var/tmp" PORTDIR="/usr/portage" PORTDIR_OVERLAY="" SYNC="rsync://rsync.gentoo.org/gentoo-portage" USE="X alsa apache2 apm arts avi berkdb cdr cjk crypt cups dedicated dga doc dvd dvdr encode esd flac foomaticdb gdbm gif gnome gpm gstreamer gtk gtk2 guile imagemagick imlib ipv6 jpeg kde lcms libg++ libwww mad memlimit mikmod mmx motif mozilla mpeg mysql ncurses nls oggvorbis opengl oss pam pdflib perl png python qt quicktime readline samba sdl slang speex spell ssl subversion svga svn tcpd threads tiff truetype usb x86 xinerama xml2 xmms xv zlib"
Created attachment 28590 [details] Test Program This is the test program which reveals the bug.
Thanks to Jon Atkins for helping me with this. The problem is in your code. You need to add a SDL_SetVideoMode(...., SDL_OPENGL); to the SDL portion of your test code. This will give the SDL_GL_GetProcAddress function the context it needs to get the function addresses.
