Upload D3D12 field resources

docs/d3d12-best-practices-audit.md

@@ -36,6 +36,10 @@ resource graph beyond smoke-pass scaffolding.
   up-facing gravity quad per body. The target is scalar `R16_Float`: height is
   one value, and the format still supports the additive render-target blending
   the brush pass needs. Mode `11` exposes it.
+- D3D12 uploads the live froxel primitive table and field instance table into
+  default-heap structured buffers each frame, using the upload ring only as the
+  copy source. Their SRVs are created in the transient descriptor heap used by
+  the consuming pass, avoiding impossible static+transient heap co-binding.
 - Renderer calls receive current window dimensions, and the D3D12 backend can
   recreate swapchain buffers plus dependent smoke resources on resize.
 - Resize waits for the GPU, disposes swapchain-dependent targets, rebuilds
@@ -63,6 +67,9 @@ resource graph beyond smoke-pass scaffolding.
 - The offscreen smoke target copies to the swapchain. Keep this only if the real
   post-process graph needs it; otherwise present from the final render target
   path with no ornamental copy.
+- The D3D11 and D3D12 field table builders are temporarily duplicated. Extract
+  them into one shared field ABI owner before the second backend starts to
+  drift.
 
 ## Required Before Real Pass Migration
 

docs/d3d12-migration.md

@@ -24,6 +24,11 @@ has feature parity.
   draws one additive up-facing gravity quad per body into a 128x128
   scalar `R16_Float` Grid height target. Render debug mode `11` displays that
   target.
+- D3D12 now owns the first field-resource upload path: CPU-built froxel
+  primitive ids and field instances upload through the per-frame upload ring,
+  copy into default-heap structured buffers, and bind as transient SRVs for the
+  diagnostic shader. This proves the backend can feed real Aquarium field data
+  without reading directly from upload memory.
 - Resize waits for the GPU, releases swapchain-dependent resources, rebuilds
   static shader/RTV descriptor arenas, then recreates backbuffer views and
   dependent render targets. Descriptor exhaustion on resize is no longer a

docs/hlsl-renderer.md

@@ -83,6 +83,13 @@ scalar `R16_Float` Grid height target. D3D12 render debug mode `11` displays
 that target. D3D11 remains the visual reference until the full pass chain
 reaches parity.
 
+D3D12 also uploads the current froxel primitive id table and field instance
+table into default-heap structured buffers every frame. The diagnostic smoke
+shader reads both SRVs through the transient descriptor heap; this is only a
+resource-path proof, not the migrated scene or medium pass yet. The D3D11 and
+D3D12 table builders should be collapsed into one shared field ABI before more
+field consumers are ported.
+
 The shader far distance is frame-derived, not a fixed constant. C# sends the
 distance from the camera to the Grid origin plus the Grid radius, which matches
 the circular Grid fade boundary and avoids wasting raymarch work past the