this sucks, but there is hope

res/shaders/MeshletBasePass.slang

@@ -52,7 +52,7 @@ void taskMain(
 				uint index;
 				InterlockedAdd(head, 1, index);
 				p.meshletId[index] = m;
-				p.instanceId[index] = groupID;
+				p.instanceId[index] = groupID + pScene.primitiveIndices[m];
 			}
 		}
 	}
@@ -90,9 +90,9 @@ void meshMain(
 	{
 		uint p = min(i, m.primitiveCount - 1);
 		{
-			uint local_idx0 = unpackPrimitiveIndices(m.primitiveOffset + (p * 3) + 0);
-			uint local_idx1 = unpackPrimitiveIndices(m.primitiveOffset + (p * 3) + 1);
-			uint local_idx2 = unpackPrimitiveIndices(m.primitiveOffset + (p * 3) + 2);
+			uint local_idx0 = pScene.primitiveIndices[m.primitiveOffset + (p * 3) + 0];
+			uint local_idx1 = pScene.primitiveIndices[m.primitiveOffset + (p * 3) + 1];
+			uint local_idx2 = pScene.primitiveIndices[m.primitiveOffset + (p * 3) + 2];
 			indices[p] = uint3(local_idx0, local_idx1, local_idx2);
 		}
 	}

res/shaders/lib/Scene.slang

@@ -42,6 +42,5 @@ struct Scene
 	StructuredBuffer<uint32_t> primitiveIndices;
 	StructuredBuffer<uint32_t> vertexIndices;
 };
-layout(set=2)
 ParameterBlock<Scene> pScene;
 

res/shaders/test.json

@@ -0,0 +1,77 @@
+{
+  "EntryPoint": "taskMain",
+  "FunctionConstants": [],
+  "NeedsFunctionConstants": false,
+  "Resources": [
+    {
+      "abIndex": 0,
+      "slot": 0,
+      "type": "SRV"
+    },
+    {
+      "abIndex": 1,
+      "slot": 1,
+      "type": "SRV"
+    },
+    {
+      "abIndex": 2,
+      "slot": 2,
+      "type": "SRV"
+    },
+    {
+      "abIndex": 3,
+      "slot": 3,
+      "type": "SRV"
+    },
+    {
+      "abIndex": 4,
+      "slot": 0,
+      "type": "CBV"
+    }
+  ],
+  "ShaderID": "2266638404583382645",
+  "ShaderType": "Amplification",
+  "TopLevelArgumentBuffer": [
+    {
+      "EltOffset": 0,
+      "Size": 24,
+      "Slot": 0,
+      "Space": 2,
+      "Type": "SRV"
+    },
+    {
+      "EltOffset": 24,
+      "Size": 24,
+      "Slot": 1,
+      "Space": 2,
+      "Type": "SRV"
+    },
+    {
+      "EltOffset": 48,
+      "Size": 24,
+      "Slot": 2,
+      "Space": 2,
+      "Type": "SRV"
+    },
+    {
+      "EltOffset": 72,
+      "Size": 24,
+      "Slot": 3,
+      "Space": 2,
+      "Type": "SRV"
+    },
+    {
+      "EltOffset": 96,
+      "Size": 24,
+      "Slot": 0,
+      "Space": 1,
+      "Type": "CBV"
+    }
+  ],
+  "max_payload_size_in_bytes": 4096,
+  "num_threads": [
+    128,
+    1,
+    1
+  ]
+}