MSAA support for the main framebuffer is not implemented on iOS right now, unfortunately.
The main framebuffer on iOS is really an OpenGL ES Framebuffer Object, which means proper MSAA support involves an explicit MSAA resolve (via glBlitFramebuffer or glResolveMultisampleFramebufferAPPLE calls, depending on the OpenGL ES version.)
SDL_GL_SwapBuffers would of course be able to call those functions internally and hide those details, but if you were to call glReadPixels it would fail unless you first explicitly resolved the MSAA color buffer to a non-MSAA color buffer, and then bound the non-MSAA color buffer to the read framebuffer binding point, before calling glReadPixels.
So I haven?t added MSAA support for the default framebuffer on iOS (yet), because I haven?t been able to reconcile the fact that users expecting glReadPixels calls to work as expected without any modifications to their code will be surprised and disappointed.
If anyone has suggestions for that, I?d be happy to hear them though.
(I originally sent this from the wrong email account by accident, so I apologize if the same reply is posted twice.)> On Jun 30, 2015, at 12:07 PM, spartanjjj wrote:
I haven’t found information about this so i have to ask.
Im using latest SDL2 on iOS. Create a window with high dpi, fullres on iphone6, i pass SAMPLES = 2 or 4, all goes well.
The problem is that it doesn’t really seem like AntiAliasing is ON.
Actually changing samples from 2 to 4 or 0 doesn’t really make much of a difference visually.
I have also used GetAttribute and GetInteger to return the number of samples for current context and it gives me the right value i used to create it in the first place.
Is there a known issue with AA on iOS? Is there a way to enable multi-sampling? Using glEnable( GL_MULTISAMPLE ) doesn’t work. GL_MULTISAMPLE is not found in the GL headers.
Appreciate any help, thank you
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