From 3cb352d2e4a2c03c92363671c19e6179a7a113af Mon Sep 17 00:00:00 2001
From: Meta Vens <rwvens@hotmail.com>
Date: Thu, 28 May 2026 21:10:18 +0100
Subject: [PATCH] Preserve all shared reservoir rows

---
 src/Aquarium.Engine/Render/Shaders/D3D12Post.hlsl | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/src/Aquarium.Engine/Render/Shaders/D3D12Post.hlsl b/src/Aquarium.Engine/Render/Shaders/D3D12Post.hlsl
index fa79037..39ae169 100644
--- a/src/Aquarium.Engine/Render/Shaders/D3D12Post.hlsl
+++ b/src/Aquarium.Engine/Render/Shaders/D3D12Post.hlsl
@@ -657,14 +657,21 @@ ResolveOut D3D12ReservoirPresentationResolvePS(VertexOut input)
     float bestPriority = 1.0e20;
     float combinedHistoryWeight = 0.0;
     float combinedHistoryAge = 0.0;
+    bool hasSharedCandidate = false;
 
     [unroll]
     for (uint slot = 0u; slot < FieldReservoirSlotsPerPixel; slot++)
     {
-        FieldReservoirCandidate currentCandidate = sceneCandidate;
-        if (slot > 0u)
+        hasSharedCandidate = hasSharedCandidate || fieldReservoirCandidateValid(fieldReservoirCandidates[baseIndex + slot]);
+    }
+
+    [unroll]
+    for (uint slot = 0u; slot < FieldReservoirSlotsPerPixel; slot++)
+    {
+        FieldReservoirCandidate currentCandidate = fieldReservoirCandidates[baseIndex + slot];
+        if (!hasSharedCandidate && slot == 0u)
         {
-            currentCandidate = fieldReservoirCandidates[baseIndex + slot - 1u];
+            currentCandidate = sceneCandidate;
         }
 
         float slotHistoryWeight;