HYDRA-973 - set HDST_RENDER_SELECTED_EDGE_FROM_FACE as 0 by default (#…

…171)

* set HDST_RENDER_SELECTED_EDGE_FROM_FACE as 0 by default

* fix build warning on Mac/Linux

lib/mayaHydra/mayaPlugin/plugin.cpp

@@ -69,6 +69,16 @@ namespace {
     std::vector<PXR_NS::MtohRenderOverride*> _renderOverrides;
 
     std::vector<MCallbackId> _pluginLoadingCallbackIds;
+
+    void setEnvVar(const char* envVarSet)
+    {
+        // putenv requires char* and I'm not willing to use const cast!
+        const auto        envVarSize = strlen(envVarSet) + 1;
+        std::vector<char> envVarData;
+        envVarData.resize(envVarSize);
+        snprintf(envVarData.data(), envVarSize, "%s", envVarSet);
+        putenv(envVarData.data());
+    }
 }
 
 void initialize()
@@ -133,14 +143,11 @@ PLUGIN_EXPORT MStatus initializePlugin(MObject obj)
         return ret;
     }
 
-    // For now this is required for the HdSt backed to use lights.
-    // putenv requires char* and I'm not willing to use const cast!
-    constexpr const char* envVarSet = "USDIMAGING_ENABLE_SCENE_LIGHTS=1";
-    const auto            envVarSize = strlen(envVarSet) + 1;
-    std::vector<char>     envVarData;
-    envVarData.resize(envVarSize);
-    snprintf(envVarData.data(), envVarSize, "%s", envVarSet);
-    putenv(envVarData.data());
+    // For now this is required for the HdSt backend to use lights.
+    setEnvVar("USDIMAGING_ENABLE_SCENE_LIGHTS=1");
+
+    // Performance optimization: disable RENDER_SELECTED_EDGE_FROM_FACE feature that could trigger unnecessary running of gometry shader.
+    setEnvVar("HDST_RENDER_SELECTED_EDGE_FROM_FACE=0");
 
     MFnPlugin plugin(obj, "Autodesk", PLUGIN_VERSION, "Any");