Re: ARB and Cygwin

[Alexander Gottwald <alexander dot gottwald at s1999 dot tu-chemnitz dot de>]

On Mon, 21 Mar 2005, Ajay Jayant Joshi wrote:

> Hi
> 
> Is it possible to use ARB extensions (shaders) under cygwin?
> I am not able to use glGenProgramsARB_t()
> ---------------------------------------------------------------
> // Generate a valid program ID
> // m_program_id => GLuint m_program_id ;
> glGenProgramsARB_t(1, &m_program_id);
> assert(m_program_id);
> // typedef void (APIENTRY * glGenProgramsARB_t) (GLsizein, GLuint*);
> ---------------------------------------------------------------
> 
> This assertion fails. I am using same code under Linux and it works fine.
> 
> Under Linux I am using:
> -- ATI FireGL (256MB) card
> -- fglrx drivers
> -- ARB vertex and fragment shaders
> 
> I am using same card and same shaders on windows (cygwin). And have
> installed latest Fire X series drivers for XP from ATI. Do i need to
> install any drivers in cygwin?
> ( i am using "/lib/w32api/libopengl32.a" as libGL.a (sym link) )

- link with /usr/X11R6/lib/libGL.a (this is the GLX wrapper)
- use XWin_GL.exe instead of XWin.exe
- your graphics card vendor must ship OpenGL drivers for windows which 
  support the extension

If you're still experiencing problems check the output of XWin_GL for messages
from glwrap. It should either print success if the OpenGL function was found
in the driver or print an error.

> glxinfo on Linux shows :
> Direct Rendering : YES
> OpenGL Drivers: ATI
> 
> glxinfo on Windows (Cygwin) shows:
> Direct Rendering : NO
> OpenGL Drivers: MESA
> 
> Can that be a problem? (When latest drivers were not installed on Linux i
> got exactly same assertion failure and when i used new drivers everything
> was ok.)
> 
> How do we make cygwin aware of underlying ATI card?
> Is direct rendering equivalent to using vertext/fragment shaders ?
> (i.e. do I need direct rendering=YES for using ARB shaders ? )

direct rendering means using the DRI framework. On linux only the DRI path is 
accelerated. Other OS can have acceleration for the indirect path too. Cygwin
doesn't even support DRI.

bye
	ago
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 Alexander.Gottwald@s1999.tu-chemnitz.de 
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