Merge pull request #2886 from johnhaddon/instancerFix

Instancer : Fix division by zero bug
GafferHQ · Nov 2, 2018 · 37eb5fd · 37eb5fd
2 parents 5bc0c86 + 55d070a
commit 37eb5fd
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Showing 2 changed files with 18 additions and 3 deletions.
diff --git a/python/GafferSceneTest/InstancerTest.py b/python/GafferSceneTest/InstancerTest.py
@@ -945,5 +945,17 @@ def testEditAttributes( self ) :
 			} )
 		)
 
+	def testUnconnectedInstanceInput( self ) :
+
+		plane = GafferScene.Plane()
+		plane["sets"].setValue( "A" )
+		plane["divisions"].setValue( imath.V2i( 1, 500 ) )
+
+		instancer = GafferScene.Instancer()
+		instancer["in"].setInput( plane["out"] )
+		instancer["parent"].setValue( "/plane" )
+
+		self.assertEqual( instancer["out"].set( "A" ).value.paths(), [ "/plane" ] )
+
 if __name__ == "__main__":
 	unittest.main()
diff --git a/src/GafferScene/Instancer.cpp b/src/GafferScene/Instancer.cpp
@@ -592,10 +592,13 @@ void Instancer::compute( Gaffer::ValuePlug *output, const Gaffer::Context *conte
 			indexedInstanceChildNames.push_back( &instanceChildNames->writable() );
 		}
 
-		for( size_t i = 0, e = engine->numPoints(); i < e; ++i )
+		if( indexedInstanceChildNames.size() )
 		{
-			size_t instanceIndex = engine->instanceIndex( i ) % indexedInstanceChildNames.size();
-			indexedInstanceChildNames[instanceIndex]->push_back( InternedString( engine->instanceId( i ) ) );
+			for( size_t i = 0, e = engine->numPoints(); i < e; ++i )
+			{
+				size_t instanceIndex = engine->instanceIndex( i ) % indexedInstanceChildNames.size();
+				indexedInstanceChildNames[instanceIndex]->push_back( InternedString( engine->instanceId( i ) ) );
+			}
 		}
 
 		static_cast<AtomicCompoundDataPlug *>( output )->setValue( result );