Transparency Sorting On The Sgx

[TheGoodDoktor]

Hi

Years ago when I worked on the Dreamcast one of the features it had which we really liked was the fact that it sorted transparencies. Now the SGX is a descendant of the CLX2(the DC's Holly chip) I was always under the impression that it would sort transparencies too but I can't find any documentation to confirm that it does. The only thing I found related to transparency sorting was a performance tip saying that transparencies should be rendered after the opaque scene (naturally) and that it was advisable to sort them on the CPU. This would suggest that this handy feature has been removed.
In a nutshell: I'm still going to render my transparencies after the opaque scene but should I sort by depth or by texture?

 

[darkblu]

sadly, pixel-depth-sorted translucencies are no longer with us.

in case you care about blendings being (marginally) correct, depth-sorting your draws is the only way.

 

[TheGoodDoktor]

OK, never mind I guess they had their reasons.
I suppose if I am depth sorting transparencies myself I can try rendering them without a discard in the fragment shader.

 

[darkblu]

OK, never mind I guess they had their reasons.
I suppose if I am depth sorting transparencies myself I can try rendering them without a discard in the fragment shader.

well, discard is a darn expensive op for opaque fragments, but i don't know how costly it is for translucent. i'd guess you just need to make sure you don't depth-write for the translucent discard-ing fragments (i.e. you don't effectively treat them as opaques).