ARB_transform_feedback_overflow_query For Intel's Mesa Driver

[phoronix]

Phoronix: ARB_transform_feedback_overflow_query For Intel's Mesa Driver

Intel's Mesa driver is at OpenGL 4.5 compliance but there are many extensions still left to be implemented that haven't appeared in a formal OpenGL specification. One of those extensions now being implemented is ARB_transform_feedback_overflow_query...

http://www.phoronix.com/scan.php?page=news_item&px=i965-ARB_trans_feed_of_query

[schmidtbag]

So here's something I never really understood - if there are extensions that aren't part of the main OpenGL specification, why do they exist, what uses them, and why were they not made part of the main spec?

[Krejzi]

ARB_gpu_shader_int64 has landed, too.

[Krejzi]

So here's something I never really understood - if there are extensions that aren't part of the main OpenGL specification, why do they exist, what uses them, and why were they not made part of the main spec?

They are part of official OpenGL spec, just not part of any OGL version, mainly because KHR didn't think they had enough exts to make OGL 4.6 happen.

http://www.phoronix.com/scan.php?page=article&item=sig-gles32-glu

[smitty3268]

So here's something I never really understood - if there are extensions that aren't part of the main OpenGL specification, why do they exist, what uses them, and why were they not made part of the main spec?

Most of the extensions that end up as part of the main OpenGL specs start out as vendor extensions first. NVidia, AMD, or another hardware vendor comes up with them - perhaps in concert with a particular engine/user, and other times simply to expose hardware capabilities they want to advertise - and then they see how interested others are in it. Sometimes they go it alone, other times there is more interest and you have a couple of different vendors cooperate - an EXT extension is born. Usually only after it's proven useful and everyone agrees they like it do they then get taken into the main GL spec.