Previously it was packed into spare slots in clippos.xy and normal.w,
but it's ugly and more importantly it's causing bugs.
This was discovered during the debugging of a zfreeze branch, which
expected clippos.xy to be xy position coordinates in clipspace (as
the name suggested).
Turns out the stereoscopy shader had also run into this trap, modifying
clippos.x (introducing errors with per-pixel lighting).
This commit has been moved outside of the zfreeze PR for fast merging.
Just use regular boolean negation in our pixel shader's depth test everywhere except on Qualcomm.
This works around a bug in the Intel Windows driver where comparing a boolean value against true or false fails but boolean negation works fine.
Quite silly.
Should fix issues #7830 and #7899.
This particular bug from our friends over at Qualcomm manifests itself due to our alpha testing code having a conditional if statement in it.
This is a fairly recent breakage this time around, it was introduced in the v95 driver which comes with Android 5.0 on the Nexus 5.
So to break this issue down; In our alpha testing code we have two comparisons that happen and if they are true we will continue rendering, but if
they aren't true we do an early discard and return. This is summed up with a fairly simple if statement.
if (!(condition_1 <logic op> condition_2)) { /* discard and return */ }
This particular issue isn't actually due to the conditions within the if statement, but the negation of the result. This is the particular issue that
causes Qualcomm to fall flat on its face while doing so.
I've got two simple test cases that demonstrate this.
Non-working: http://hastebin.com/evugohixov.avrasm
Working: http://hastebin.com/afimesuwen.avrasm
As one can see, the disassembled output between the two shaders is different even though in reality it should have the same visual result.
I'm currently writing up a simple test program for Qualcomm to enjoy, since they will be asking for one when I tell them about the bug.
It will be tracked in our video driver failure spreadsheet along with the others.
In the cases where we support the binding layout keyword, use it for more than binding UBO location.
This changes it so it is supported for samplers as well.
Instances when this is enabled is if a device supports GL_ARB_shading_language_420pack, or if it supports GLES 3.10.
Scott Mansell