Posted by Jeffg on Dec 10, 2011; 5:05pm
URL: https://forum.jogamp.org/What-profile-to-choose-tp3575514p3575677.html

Thanks for the info - I've read through the links you posted.  Here is some of my confusion - I use shaders, so I know I utilize the programmable pipeline, but I'm less clear on what calls represent a fixed pipeline call.  For example, let's say I create a display list that creates a quad, no shader called, is that using the fixed pipeline?

Also, I guess I'm having trouble understanding if compatibility is for the API or OpenGL itself.  For example, does using GL3 or GL4 make you're application incompatible with someone running OpenGL 2.1 if you don't make calls that 2.1 doesn't support?  If so, does using GL4bc change that, or does it just allow your API to use commands that are part of the fixed pipeline (again, which I don't quite get).  Why would you use GL3bc over GL4bc, if GL4bc is backward compatible?  I think I understand the mobile vs desktop, as the mobile profile would probably prevent you from calling things that are not available on mobile devices.  Is that the same with GL2 vs GL3.. GL2 just prevents you from making calls to commands only available on OpenGL 3.1?  If you used GL3, but didn't make calls above a GL2 level, would you gain anything by using a higher GL level.. so if the user had installed OpenGL 3.1, would using GL3 with GL2 calls improve performance or anything?

Sorry for all the questions - I appreciate the assistance.
- Jeff