so how is that being finished precisely?
With devoted {hardware} paths particularly designed to optimize this widespread process, and never accessible so that you can customise programmatically past turning depth testing and writes on/off, or altering the comparability used.
may I as a substitute select to jot down the depth of furthest fragments (e.g. “Larger” depth comparability), and draw shade as closest as ordinary.
No. There usually are not actually two separate writes taking place right here, only one. Both the depth check passes, and each color and depth are written (if color and depth writes are enabled, respectively), or the depth check fails, and neither are written.
So whilst you can change the route of the depth check to less-than or greater-than, the identical check is at all times used for the entire fragment, each color and depth elements.
You may management what depth to output within the fragment shader by writing a worth to the particular DEPTH semantic, however doing so disables some optimizations associated to “early z rejection”. The {hardware} pipeline can now not decide whether or not the fragment will probably be occluded till the fragment shader has been run, so it has to run the complete shader even for fragments which can by no means be seen.
You can obtain one thing much like this with a number of passes, rendering your content material as soon as with a “Much less” check and saving the ensuing depths to 1 buffer, then rendering your content material a second time with a “Larger” check, and studying the buffer you beforehand saved to do no matter computations you need that depend on understanding each the best and least depth values at a degree.
You may additionally need to look into the strategy of “depth peeling” which is utilized in some order-independent transparency approaches.
