- Replace dark edge RGB on alpha-tested foliage with mip-4 average color
proportional to alpha (low alpha = low trust in original RGB)
- Raise foliage alpha cutoff to 0.4 and remove dither band for cleaner edges
- Disable depth test on insect particles so they don't vanish behind foliage
- Exempt dragonflies/butterflies/moths from foliage animation freeze
Shadow casting: foliage batches now bind their actual texture in the shadow
pass with alpha testing, producing leaf-shaped shadows instead of solid cards.
Uses a per-frame resettable descriptor pool for texture sets.
Shadow receiving: foliage fragments now sample the shadow map with PCF
instead of using a flat constant darkening.
Replaces single-tap shadow sampling with 3x3 grid PCF (36-sample equivalent
with hardware bilinear filtering) for smooth shadow edges. Adds normal-offset
bias to eliminate shadow acne on oblique surfaces without peter-panning.
