HYDRA-500 : Fix directional and default lights not working.

Autodesk · Nov 9, 2023 · ee77196 · ee77196
1 parent d78bd1b
commit ee77196
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Showing 3 changed files with 13 additions and 5 deletions.
diff --git a/lib/mayaHydra/hydraExtensions/adapters/directionalLightAdapter.cpp b/lib/mayaHydra/hydraExtensions/adapters/directionalLightAdapter.cpp
@@ -53,11 +53,14 @@ class MayaHydraDirectionalLightAdapter : public MayaHydraLightAdapter
 
     void _CalculateLightParams(GlfSimpleLight& light) override
     {
+        //To simulate a directional light which has no actual position, but doesn't seem to be supported in hydra, we set a position very very far
+        //so it looks like a directional light.
         // Directional lights point toward -Z, but we need the opposite
         // for the position so the light acts as a directional light.
-        const auto direction = GfVec4f(0.0, 0.0, 1.0, 0.0) * GetTransform();
+        static const double farfarAway {1.0e15};//we use a point on the Z axis far far away
+        const GfVec4d direction = farfarAway * GetTransform().GetRow(2);//Equivalent to GfVec4d(0.0, 0.0, farfarAway, 0.0) * GetTransform();
         light.SetHasShadow(true);
-        light.SetPosition({ direction[0], direction[1], direction[2], 0.0f });
+        light.SetPosition({ (float)direction[0], (float)direction[1], (float)direction[2], 0.0f });
     }
 
     VtValue Get(const TfToken& key) override

diff --git a/lib/mayaHydra/hydraExtensions/adapters/lightAdapter.cpp b/lib/mayaHydra/hydraExtensions/adapters/lightAdapter.cpp
@@ -190,7 +190,7 @@ VtValue MayaHydraLightAdapter::Get(const TfToken& key)
             GetGfMatrixFromMaya(GetDagPath().inclusiveMatrixInverse()));
 #else
         light.SetTransform(
-            GetGfMatrixFromMaya(GetDagPath().inclusiveMatrix()));
+            GetGfMatrixFromMaya(inclusiveMatrix));
 #endif
         _CalculateLightParams(light);
         return VtValue(light);

diff --git a/lib/mayaHydra/mayaPlugin/renderOverride.cpp b/lib/mayaHydra/mayaPlugin/renderOverride.cpp
@@ -435,10 +435,15 @@ void MtohRenderOverride::_DetectMayaDefaultLighting(const MHWRender::MDrawContex
                 considerAllSceneLights);
 
             if (hasDirection && !hasPosition) {
+
+                //To simulate a directional light which has no actual position, but doesn't seem to be supported in hydra, we set a position very very far
+                //so it looks like a directional light.
+                static const float farfarAway {1.0e15f};//we use a point on the Z axis far far away
+
                 // Note for devs : if you update more parameters in the default light, don't forget
-                // to update MtohDefaultLightDelegate::SetDefaultLight currently there are only 3 :
+                // to update MtohDefaultLightDelegate::SetDefaultLight and MayaHydraSceneIndex::SetDefaultLight, currently there are only 3 :
                 // position, diffuse, specular
-                _defaultLight.SetPosition({ -direction.x, -direction.y, -direction.z, 0.0f });
+                _defaultLight.SetPosition({ -farfarAway*direction.x, -farfarAway*direction.y, -farfarAway*direction.z, 0.0f });
                 _defaultLight.SetDiffuse(
                     { intensity * color.r, intensity * color.g, intensity * color.b, 1.0f });
                 _defaultLight.SetSpecular(