SL-19000 Fix various 3D UI components not respecting depth buffer.  Incidental decruft.  Do I get a prize for 1000th jira?

SL-19015 Balance sun/sky ambiance with punctual light ambiance.  Prevent irradiance maps from being brighter than the environment.

SL-19015 Bump probe resolution back to 256 by default (drop to 128 if vram < 2GB), remove irradiance map feedback loop (one bounce, but but more stable and allows for much brighter first bounce), make sky contribution to irradiance not tint the world blue.  Make irradiance that appears in radiance maps match world irradiance.

* SL-19203 WIP -- Integrate SSR with reflection probes.  Decruft LLRenderTarget.

* SL-19203 WIP -- Re-integrate SSR.  Incidental decruft.

* SL-19203 WIP -- SSR frame delta correction (still broken for Z)

* SL-19203 WIP -- SSR frame delta Z fix

* SL-19203 WIP -- Make SSR toggleable again and disable SSR in cube snapshots.

* SL-19203 WIP -- Soften sphere probe transitions and fix reflections on void water (make fallback probe a simple terrain+water+sky probe).  Remove parallax correction for automatic probes to reduce artifacts.

* SL-19203 Tune probe blending.

* SL-19203 Cleanup.

SL-18869, SL-18772  Overhaul VBO management, restore occlusion culling, intel compatibility pass, etc

SL-18869 Touch up -- Prune "post_pos" from shadow shaders that don't need it and fix non-standard gl_Position z values

SL-18869 Optimizations -- Revive "Frame Profile" and GL_DEPTH_CLAMP.  Remove usage of gl_FragDepth from shadow shaders.

SL-18869 Optimizations -- Decruftify LLRenderTarget, use a shader to copy color/depth instead of glCopyTexSubImage or glBlitFrameBuffer

Fixes SL-18484.

SL-18692 Fix for fullbright alpha not clipping against water plane (also fixes ultraspace particles).

SL-18662

Mostly just making it actually kind of work.  Still needs a lot more tweaking - but can revisit later.
SL-18332

original fix by Beq Janus

Jonathan Goodman authored 2 years ago and David Parks committed 2 years ago

First pass of Screen Space Reflections

Approved-by: Dave Parks

This is the most local fix for this issue, addressing the specific unqualified use of HAS_ALPHA_MASK.
If we find other issues with alpha mask being applied incorrectly then, it may be better to fix higher up in llvieweshadermgr.cpp by reverting the changes from SL-17532. 
For now, this way works for this specific bug without non-emissive side-effects.

SL-18485: Render GLTF materials with extension KHR_texture_transform with approprate texture transforms

SL-18453 WIP -- Use GLTF draw pool to render shadows.  Still need a GLTF specific shadow shader to multiply alpha.

SL-18105 Clean up class1/deferred/materialF.glsl (merge cleanup), make override messaging LLSD where it ought to be and JSON where it ought to be.