I was reading about multi-pass rendering on mobile devices
(https://developer.oculus.com/blog/loads-stores-passes-and-advanced-gpu-pipelines/)
and discovered that I had used the wrong flags (but then, I think Graham
Sellers had, too, since used his Vulkan Programming Guide as a
reference). Doesn't seem to make any difference on desktop, but as
there's no loss there, but potential gains on mobile, I'd say it's a
win.
There were actually several problems: translucency wasn't using or
depending on the depth buffer, and the depth buffer wasn't marked as
read-only in the g-buffer pass. Getting that correct seems to have given
bigass1 a 0.5% boost (hard to say, could be the usual noise).
That was... easier than expected. A little more tedious that I would
have liked, but my scripting system isn't perfect (I suspect it's best
suited as the output of a code generator), and the C side could do with
a little more automation.
While I could reconstruct the position from the screen coords and depth,
this is easier and good enough for now. Reconstruction is an
optimization thing.
Lighting doesn't actually do lights yet, but it's producing pixels.
Translucent seems to be working (2d draw uses it), and compose seems to
be working.
After getting lights even vaguely working for alias models, I realized
that it just wasn't going to be feasible to do nice lighting with
forward rendering. This gets the bulk of the work done for deferred
rendering, but still need to sort out the shaders before any real
testing can be done.
