About 555 or 565 format for OpenGL under SDL?

SDL Development
1

hi,

I need some help about OpenGL under SDL.

how to know if my graphics card is a 555 or 565 in 16 bits ?
see ->

SDL_GL_SetAttribute( SDL_GL_RED_SIZE, 5 );
SDL_GL_SetAttribute( SDL_GL_GREEN_SIZE, 5 ); // or SDL_GL_GREEN_SIZE, 6
SDL_GL_SetAttribute( SDL_GL_BLUE_SIZE, 5 );
SDL_GL_SetAttribute( SDL_GL_DEPTH_SIZE, 16 );

Thanks alot.

Laurent_________________________________________________________________
T?l?chargez MSN Explorer gratuitement ? l’adresse
http://explorer.msn.fr/intl.asp.

2

hi,

I need some help about OpenGL under SDL.

how to know if my graphics card is a 555 or 565 in 16 bits ?
see ->

SDL_GL_SetAttribute( SDL_GL_RED_SIZE, 5 );
SDL_GL_SetAttribute( SDL_GL_GREEN_SIZE, 5 ); // or SDL_GL_GREEN_SIZE, 6
SDL_GL_SetAttribute( SDL_GL_BLUE_SIZE, 5 );
SDL_GL_SetAttribute( SDL_GL_DEPTH_SIZE, 16 );

Pick the most bits, and you’ll get what the card has:

SDL_GL_SetAttribute( SDL_GL_RED_SIZE, 8 );
SDL_GL_SetAttribute( SDL_GL_GREEN_SIZE, 8 );
SDL_GL_SetAttribute( SDL_GL_BLUE_SIZE, 8 );

If you need to know what you actually got, use the GetAttribute() call.

See ya,
-Sam Lantinga, Software Engineer, Blizzard Entertainment

3

Actually Sam, I think that will fail in 16 bit mode. The GL attributes
are intended to be smallest-acceptable, not largest-available. To use
whatever you have, you should set all four of the above to 1.On Mon, Apr 08, 2002 at 10:48:10AM -0700, Sam Lantinga wrote:

I need some help about OpenGL under SDL.

how to know if my graphics card is a 555 or 565 in 16 bits ?
see ->

SDL_GL_SetAttribute( SDL_GL_RED_SIZE, 5 );
SDL_GL_SetAttribute( SDL_GL_GREEN_SIZE, 5 ); // or SDL_GL_GREEN_SIZE, 6
SDL_GL_SetAttribute( SDL_GL_BLUE_SIZE, 5 );
SDL_GL_SetAttribute( SDL_GL_DEPTH_SIZE, 16 );

Pick the most bits, and you’ll get what the card has:

SDL_GL_SetAttribute( SDL_GL_RED_SIZE, 8 );
SDL_GL_SetAttribute( SDL_GL_GREEN_SIZE, 8 );
SDL_GL_SetAttribute( SDL_GL_BLUE_SIZE, 8 );

If you need to know what you actually got, use the GetAttribute() call.

–
Joseph Carter Sanity is counterproductive

  • Culus thinks we should go to trade shows and see how many people we
    can kill by throwing debian cds at them

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4

Actually Sam, I think that will fail in 16 bit mode. The GL attributes
are intended to be smallest-acceptable, not largest-available. To use
whatever you have, you should set all four of the above to 1.

Interesting, I was under the impression it was the other way around.
Any GL gurus who can shed some light on the subject?

Where’s Daniel when you need him, eh? :slight_smile:

See ya,
-Sam Lantinga, Software Engineer, Blizzard Entertainment

5

man glXChooseVisual says:

   GLX_RED_SIZE          Must  be  followed  by a nonnegative
                         minimum size specification.  If this
                         value  is  zero, the smallest avail?
                         able red buffer is preferred.   Oth?
                         erwise,  the  largest  available red
                         buffer of at least the minimum  size
                         is preferred.

The same applies to the other sizes.On Mon, Apr 08, 2002 at 09:05:24PM -0700, Sam Lantinga wrote:

Actually Sam, I think that will fail in 16 bit mode. The GL attributes
are intended to be smallest-acceptable, not largest-available. To use
whatever you have, you should set all four of the above to 1.

Interesting, I was under the impression it was the other way around.
Any GL gurus who can shed some light on the subject?

Where’s Daniel when you need him, eh? :slight_smile:

–
Joseph Carter Crazy in the coconut

Ben: Do you solumly swear to read you debian email once a day and
do not permit people to think you are MIA?
Culus: i do so swear

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6

Joseph Carter said:----------------------------------
man glXChooseVisual says:

   GLX_RED_SIZE          Must  be  followed  by a nonnegative
                         minimum size specification.  If this
                         value  is  zero, the smallest avail?
                         able red buffer is preferred.   Oth?
                         erwise,  the  largest  available red
                         buffer of at least the minimum  size
                         is preferred.

The same applies to the other sizes.

Joseph is correct. By specifying zero, you request the smallest available
color component size; but specifying anything else you request the largest
color component size that is equal to or less than the size you specified.

I checked the Blue book (OGL Reference Manual.)

-Blake