MAYA-110276 - USD: curves drawing color is the exact same as the maya viewport Gray background

lib/mayaUsd/render/vp2RenderDelegate/basisCurves.cpp

@@ -962,10 +962,9 @@ void HdVP2BasisCurves::_UpdateDrawItem(
                 }
             }
 
-            // If color/opacity is not found, the 18% gray color will be used
-            // to match the default color of Hydra Storm.
+            // If color/opacity is not found, the default color of Maya curves will be used
             if (colorArray.empty()) {
-                colorArray.push_back(GfVec3f(0.18f, 0.18f, 0.18f));
+                colorArray.push_back(drawScene.GetCurveDefaultColor());
                 colorInterpolation = HdInterpolationConstant;
             }
 

lib/mayaUsd/render/vp2RenderDelegate/proxyRenderDelegate.cpp

@@ -1480,6 +1480,24 @@ HdVP2SelectionStatus ProxyRenderDelegate::GetSelectionStatus(const SdfPath& path
 //! \brief  Query the wireframe color assigned to the proxy shape.
 const MColor& ProxyRenderDelegate::GetWireframeColor() const { return _wireframeColor; }
 
+GfVec3f ProxyRenderDelegate::GetCurveDefaultColor()
+{
+    MDoubleArray curveColorResult;
+    {
+        std::lock_guard<std::mutex> _(_mayaCommandEngineMutex);
+        MGlobal::executeCommand(
+            "int $index = `displayColor -q -dormant \"curve\"`; colorIndex -q $index;",
+            curveColorResult);
+    }
+
+    if (curveColorResult.length() == 3) {
+        return GfVec3f(curveColorResult[0], curveColorResult[1], curveColorResult[2]);
+    } else {
+        // In case of an error, return the default navy-blue color
+        return GfVec3f(0.000f, 0.016f, 0.376f);
+    }
+}
+
 //! \brief
 const MColor& ProxyRenderDelegate::GetSelectionHighlightColor(bool lead) const
 {

lib/mayaUsd/render/vp2RenderDelegate/proxyRenderDelegate.h

@@ -170,6 +170,9 @@ class ProxyRenderDelegate : public MHWRender::MPxSubSceneOverride
     MAYAUSD_CORE_PUBLIC
     const MColor& GetWireframeColor() const;
 
+    MAYAUSD_CORE_PUBLIC
+    GfVec3f GetCurveDefaultColor();
+
     MAYAUSD_CORE_PUBLIC
     const MColor& GetSelectionHighlightColor(bool lead) const;
 
@@ -287,6 +290,8 @@ class ProxyRenderDelegate : public MHWRender::MPxSubSceneOverride
 #endif
     MColor _wireframeColor; //!< Wireframe color assigned to the proxy shape
 
+    std::mutex _mayaCommandEngineMutex;
+
     //! A collection of Rprims to prepare render data for specified reprs
     std::unique_ptr<HdRprimCollection> _defaultCollection;