Gravity map: B49 stardust order against the opaque fog pass (camera-event probe on the ARPG camera)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/aetheria-gravity-map.md

@@ -86,6 +86,7 @@ All read at c6519383 in the detached worktree `C:\aeth-wt\ag2-docs` on 2026-10-1
 - **B46. Stardust culling** (stardust-bounds, merged fdecde02; verdicts cut-stardust-bounds.s1/s2). The bounded Graphics.DrawProcedural was culled against a hand-set 2048-high box, and no overload opts out; the draw is now one CommandBuffer on TargetCamera at CameraEvent.BeforeForwardAlpha. Both target cameras are deferred, where AfterForwardOpaque never runs (it drew 0 pixels); BeforeImageEffects and AfterEverything also draw.
 - **B47. The ambient's edge** (ambient-follows-populated-area, merged 6865af81; verdicts .s1/.s2; ruling dark-beyond-populated-area). The only tint in the outer zone was the Ambient Fog Light quad (PowerBrush power 2) sized to exactly Pack.Radius, so the tint map was zero beyond it while the field kept rising into a rim wall: the circular light edge. Sun brushes (power 16 over LightRadius/2) are under 1% by half their radius. Now Zone.PopulatedRadius (max chain reach of bodies and belts + Roche) sets a Gaussian fade, edge 0.12 of centre, quad sized to the B10G11R11 format floor 2^-15 (last step <= 1.5 floors). The dead second marcher (VolumeRender shaders, Fog Marching materials) was deleted (dead-fog-marcher, merged 949fa005).
 - **B48. Law and generator together** (`docs/research/gravity-well-law-r3.md`, merged with its minimap renders; question tail-taming-law-r3). Recommended C4: the band law with reach 1/2 D, plus generator rules (child at least max(1.5 x parent Roche, 3 eps_c c_p/c_c), at most D_parent/6, sibling spacing D_(i+1) >= D_i/(1 - lambda/2), unfit children folded into the parent's body) keeping 20,768 of 31,640 nodes; rail honesty 0.90-1.10, planetoid cusps lost 4/4894 (today 805/10127), far field exactly c(M_zone). The closed-form band potential loses float32 precision for tau > 1; the law needs a series branch there. Blob share stays >= 0.49 under every candidate because the minimap spaces 21 contours linearly over the deepest body (IsolinesUI.shader:178): a presentation fix for grid-noise-presentation. Dead or derived generator variables: PlanetSafetyRadius, the neighbour-based ChildDistanceMaximum, distMul as spacing owner, the rosette child windows.
+- **B49. Stardust against the nebula march** (probe 2026-10-16 by imagination-ag4-stardust-order at 6b6e7c7c, Unity 6000.3.24f1 batchmode D3D11, ARPG.unity Main Camera, deferred HDR; every camera MonoBehaviour disabled, an [ImageEffectOpaque, ExecuteAlways] snapshot added that copies its source and _CameraDepthTexture; an Unlit/Color quad 50 u ahead drawn by a CommandBuffer at one event per render; log in the session scratchpad imagination-ag4-stardust-order/probe2.log). The nebula is VolumeCloudRenderer, an [ImageEffectOpaque] OnRenderImage: it marches to _CameraDepthTexture and composites mcol*(1-a)+cloud (CloudShader.shader:161, :361). Seen by the opaque effect (so fogged): BeforeLighting, AfterLighting, BeforeImageEffectsOpaque. Drawn but after it (so on top of the fog): AfterImageEffectsOpaque, BeforeForwardAlpha, which is where 1973b6d2 put the dust. Not run with no forward-opaque object or skybox: BeforeForwardOpaque, AfterForwardOpaque, BeforeSkybox, AfterSkybox. BeforeImageEffectsOpaque ran with every image effect disabled. Only BeforeGBuffer and AfterGBuffer depth writes reach _CameraDepthTexture (a deferred camera copies it from the G-buffer depth), and a single-target colour draw there lands in albedo and is unlit. So the dust has never been in the depth the march reads: before the cut (a queue-2000 renderer drawn forward after lighting) the march ran past it and laid the whole ray's fog over it, as it will again at BeforeImageEffectsOpaque. Dust in front of a cloud is fogged as if behind it; per-particle depth occlusion would need a G-buffer pass writing emission to the lighting target.
 
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