WIP : Explicit float to half binding

Author: ericmehl

src/IECorePython/HalfBinding.cpp

@@ -49,16 +49,47 @@ namespace IECorePython
 
 struct half_to_float
 {
-    static PyObject* convert( const half &x )
-    {
-        return PyFloat_FromDouble( x );
-    }
+	static PyObject* convert( const half &x )
+	{
+		return PyFloat_FromDouble( x );
+	}
+};
+
+struct HalfFromPython
+{
+	HalfFromPython()
+	{
+		converter::registry::push_back(
+			&convertible,
+			&construct,
+			type_id<half> ()
+		);
+	}
+
+	static void *convertible( PyObject *obj_ptr )
+	{
+		if ( !PyFloat_Check( obj_ptr ) )
+		{
+			return nullptr;
+		}
+		return obj_ptr;
+	}
+
+	static void construct( PyObject *obj_ptr, converter::rvalue_from_python_stage1_data *data )
+	{
+		assert( obj_ptr );
+
+		void* storage = (( converter::rvalue_from_python_storage<half>* ) data )->storage.bytes;
+		new( storage ) half( extract<float>( obj_ptr ) );
+		data->convertible = storage;
+	}
 };
 
 void bindHalf()
 {
-    to_python_converter<half, half_to_float>();
-	implicitly_convertible<float, half>();
+	to_python_converter<half, half_to_float>();
+	HalfFromPython();
+	// implicitly_convertible<float, half>();
 }
 
 }