After working around the bugs described in #93551 and getting the game running, I noticed that unless the shadow quality setting was at "Ultra", all rendered shadows are blocky and jagged, with gaps appearing between the shadows cast be apparently solid objects. I messed around with some driconf options, and discovered that this rendering issue goes away if setting the "glsl_correct_derivatives_after_discard" option. Unfortunately, I couldn't get a working apitrace because of the LD_PRELOAD hacks, but attached are two screenshots of roughly the same area, one without the option (before.png) and one with (after.png).
Created attachment 137676 [details] Without "glsl_correct_derivatives_after_discard"
Created attachment 137677 [details] With "glsl_correct_derivatives_after_discard"
Should be fixed by: commit 3c9144f9e5888e9a31886b64168f63e991da01d0 Author: Timothy Arceri <tarceri@itsqueeze.com> Date: Fri Aug 2 10:05:20 2019 +1000 drirc: Add discard workaround for Divinity: Original Sin EE This adds an additional work around for the game to fix the blocky shadows as reported in bug 105282 Acked-by: Eric Engestrom <eric.engestrom@intel.com> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105282
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