AD: Various fixes around dynamic dispatch (#2820)

* Add a test for the new diff material system

* Various fixes for AD

- inout primal context params converted to out params,
- added attributed types to list of stored types
- used differentiated primal func type instead of type of differentiated func to avoid tangling with user-code differential types.

---------

Co-authored-by: Lifan Wu <lifanw@nvidia.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/tests/autodiff/material2/DiffuseMaterial.slang b/tests/autodiff/material2/DiffuseMaterial.slang
new file mode 100644
index 000000000..721445249
--- /dev/null
+++ b/tests/autodiff/material2/DiffuseMaterial.slang
@@ -0,0 +1,26 @@
+//TEST_IGNORE_FILE:
+
+__exported import IMaterial;
+__exported import DiffuseMaterialInstance;
+
+struct DiffuseMaterial : IMaterial
+{
+    float3 baseColor;
+
+    typedef DiffuseMaterialInstance MaterialInstance;
+
+    [TreatAsDifferentiable]
+    float3 getAlbedo(float3 albedo)
+    {
+        return albedo;
+    }
+
+    [BackwardDifferentiable]
+    DiffuseMaterialInstance setupMaterialInstance(out MaterialInstanceData miData)
+    {
+        float3 albedo = getAlbedo(baseColor);
+        DiffuseMaterialInstance mi = { baseColor };
+        for (uint i = 0; i < 3; i++) miData.data[i] = albedo[i];
+        return mi;
+    }
+};