The Ray Reconstruction engine caches one immutable descriptor set per unique combination of input views (hard limit: 16). Games that rotate their intermediate textures through a ring buffer generate a new combination each frame; with K independent ring buffers of size N the number of distinct combinations grows as N^K, quickly exceeding the cache limit.
Fix: track the number of distinct VkImageView handles seen per input (11 inputs: colour, motion, depth, 8 guides). When an input exceeds 4 distinct views it is flagged as rotating and its data is copied to a canonical plane (a stable internal texture) instead of being borrowed directly. The `direct` lambda now takes an index and checks the per-input flag, so only the inputs that actually rotate incur a blit.
Stable inputs (single view, no ring buffer) continue to be borrowed directly with zero extra cost. The worst-case overhead is one blit per rotating input per frame (~0.05 ms each).
The flag is one-way: once an input is marked as rotating it stays that way for the lifetime of the engine. If a game changes its rendering mode mid-session the flag persists, adding a negligible number of extra blits.
Alan Wake 2 uses the format for depth when enabling Ray Reconstruction.
The CPU path converts half to float in convert_row_in.
The VRAM interop path blits R16F/R16UNORM depth to an R32F conversion image before copying into the canonical buffer.
Signed-off-by: Tk-Glitch <[email protected]>
Tk-Glitch