* Shadows Rewrite: C#, bindless, flexible, quality options, less VRAM...
Introduces a new shadow mapper written entirely in C#, as well as
rewritten shader code for sampling shadow maps. This fully removes and
replaces Source 2's native shadow mapping giving us greater flexibility
and allowing us to open-source it all.
The main goal for the new shadow mapper is greater flexibility whilst
reducing complexity.
Older shaders are incompatible with the new lighting buffers, and will
need to be recompiled to receive lighting properly.
What's new:
- Bindless per-light shadow maps instead of a shared shadow atlas — this
means games can avoid the shadow atlas cost if not using many shadows,
but also allows games with many shadows to not be limited by atlas
space.
- Directional lights have developer configurable cascade count (1-4) and
control over split ratio (logarithmic/uniform blend via lambda
parameter), useful for games where you may not need multiple cascades.
User quality settings define a maximum cascade count which always
overrides developer settings, allowing low end hardware to use fewer.
- Directional lights have a dedicated cbuffer and uniform fast path in
rendering code, and are no longer binned and looped over with local
lights. Every pixel on screen is always affected by a directional
light.
- CSM cascade selection uses bounding spheres instead of depth
comparison, with per-cascade texel snapping to eliminate sub-texel
shimmer.
- Point lights use a TextureCube for cube shadows for much simpler
rendering and mapping, along with hardware PCF filtering.
- Local light shadow resolution is derived from each light's screen-space
size. Shadows below a configurable threshold are not rendered at all.
Lights are sorted by screen size, and r.shadows.max caps the total
count, culling least important lights first.
- User settings have been added for shadow quality (Low/Medium/High)
controlling max resolution, max cascades, and PCF filter quality.
- Local light shadow maps use D16 depth format, halving memory compared
to D32. CSMs remain D32 for precision at large distances.
(Although this could be a TODO, I bet we could make it work in D16)
- ShadowHardness: New per-light property controlling shadow sharpness.
Defaults to soft (0.0) and scales up to 4x sharper. For directional
lights, hardness is automatically scaled per cascade proportional to
texel density (wider cascades get softer shadows), and clamped so the
filter never exceeds a full texel — ensuring consistent softness
across cascade transitions.
- Shadow debug overlay showing all information about allocated shadow maps,
their textures, cascades and more.
- Many new convars to control
- r.shadows.max: Maximum number of shadow-casting local lights, sorted by screen size, least important culled first
- r.shadows.maxresolution: Max texture size for a projected light shadow map (128–4096)
- r.shadows.quality: Shadow filter quality (0=Off, 1=Low, 2=Med, 3=High, 4=Experimental Penumbra)
- r.shadows.csm.maxcascades: Maximum number of cascades for directional light shadows (1–4)
- r.shadows.csm.maxresolution: Maximum resolution for each cascade shadow map (512–8192)
- r.shadows.csm.distance: Maximum distance from camera that directional light shadows render (500–50000)
- r.shadows.debug: Show shadow debug overlay with CSM textures, cascade bounds, and memory budget
- r.shadows.csm.enabled: Enable or disable directional light (CSM) shadows
- r.shadows.local.enabled: Enable or disable local light (spot/point) shadows
- r.shadows.depthbias: Rasterizer constant depth bias during shadow map rendering
- r.shadows.slopescale: Rasterizer slope-scaled depth bias during shadow map rendering
- r.shadows.size_cull_threshold: Screen size percentage below which local light shadows are culled
- SceneLight refactored into a base class with ScenePointLight,
SceneSpotLight, SceneDirectionalLight. SceneOrthoLight removed.
- Simplified Light.hlsl: Light is now a class, DynamicLight merged into
Light, ProbeLight and LightmappedLight no longer inherit from
DynamicLight.
- GPULight/BinnedLight struct reorganized and trimmed: explicit typed
fields instead of packed uint4 Params, shadow data replaced with a
shadow index into a separate StructuredBuffer, removed embedded shadow
matrices and atlas bounds.
- ViewLightingConfig cleaned up: removed ViewLightingFlags,
Shadow3x3PCFConstants, EnvironmentMapSizeConstants,
LegacyAmbientLightColor.
- Baked light mode flags fixed: BAKED lights (lightmaps only) no longer
create shadow maps. MIXED_SHADOWS gated to Stationary lights only
(was unconditionally applied). RENDER_ALL_GEOMETRY flag removed.
DirectLightMode enum documented across Hammer entity definitions.
- Removed light cookie sheets; cookie UV derived from light transform
(LightToWorld transpose). Cookie sampling simplified to a single
bindless texture lookup.
