[scooterman]

Hi again, I'm trying to add antialiasing support to my app, and by the SDL doc I should do this before initialize my screen:

SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, 1);

SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, 16);

But, when I try to run it, I'm receiving this error:
{}, You must create an OpenGL context before attempting to load OpenGL extension

So, how I'm supposed to load my extensions if the context will be initialized only with SDL_SetVideoMode?

Thanks,

[aldacron]

That exception is thrown from DerelictGL.loadExtensions(). That tells me that you are calling it before you call SDL_SetVideoMode. Don't
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[scooterman]

Here is my init code:


DerelictSDL.load();
SDL_Init(SDL_INIT_VIDEO);

DerelictGL.load();

SDL_EnableUNICODE(1);

SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, 1);

SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, 16);

if (GameSystem.Fullscreen)
m_screen = SDL_SetVideoMode(GameSystem.ScreenWidth, GameSystem.ScreenHeight, 32, SDL_OPENGL | SDL_FULLSCREEN);
else
m_screen = SDL_SetVideoMode(GameSystem.ScreenWidth, GameSystem.ScreenHeight, 32, SDL_OPENGL);

DerelictGL.loadExtensions();

int Buffers;
int Samples;
glGetIntegerv( GL_SAMPLE_BUFFERS_ARB, & Buffers ) ;
glGetIntegerv( GL_SAMPLES_ARB, & Samples );

Stdout.formatln("{} {}",Samples, Buffers);




And I've just confirmed that it works on my windows box, but gives that error on my linux box, on the SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, 16) line.

Strange.

[aldacron]

It's impossible for you to get the message you're seeing from a call to SDL_GL_SetAttribute, because the message is part of an Exception thrown by DerelictGL.loadExtensions when it finds that no valid OpenGL context exists.

You aren't doing any error checking on the pointer returned by SDL_SetVideoMode. If that call is failing, which it very well could be, then that would mean that no OGL context is being created, yet the loadExtensions call is still being executing because you aren't aborting on the failure. I'm willing to bet that's exactly what's happening.

So try testing the return value of SDL_SetVideoMode against null: