Does anyone know how cards like the GeForce3 are handling CopyTex*Image calls when Anti-Alias is enabled?
As far as i understand for GeForce/Radeon class chipsets, there are no mechanisms to turn AA on/off from within GL. This seems unfortunate as it could be useful or harmful to have it engage for render to textures (via CopyTex*Image)
The ‘AA’ part could create big problems if what you’re writing to the frame buffer is an object_id which you don’t want anti-aliased.
For GeForce3 the ARB_multisample extension is supported. This allows the app some control of whether this is on or off.
There’s also an NV_multisample_filter_hint extension that allows you to select the type of filtering used on the samples when resolving the multisample buffer for display.
That said, it might be more efficient to use a non-multisample pbuffer for render-to-texture though.
Do you know what the story is for GeForce2?(or Radeon anyone?). Is there means to detect if ‘AA’ has been enabled in the ‘screen-display-settings,’ and if so, any behavior to take regarding ‘Render-to-Textures’ via CopyTex or Pbuffers ?