diff --git a/code/nel/src/3d/driver/OpenGL3/driver_glsl_shader_generator.cpp b/code/nel/src/3d/driver/OpenGL3/driver_glsl_shader_generator.cpp
index 04b622a69..4ad7c09e7 100644
--- a/code/nel/src/3d/driver/OpenGL3/driver_glsl_shader_generator.cpp
+++ b/code/nel/src/3d/driver/OpenGL3/driver_glsl_shader_generator.cpp
@@ -107,11 +107,14 @@ namespace NL3D
 	{
 		material = NULL;
 		vbFormat = 0;
+		ss.str( "" );
+		ss.clear();
 	}
 
 	void CGLSLShaderGenerator::generateVS( std::string &vs )
 	{
-		std::stringstream ss;
+		ss.str( "" );
+		ss.clear();
 
 		ss << "#version 330" << std::endl;
 		ss << "uniform mat4 mvpMatrix;" << std::endl;
@@ -163,7 +166,8 @@ namespace NL3D
 
 	void CGLSLShaderGenerator::generatePS( std::string &ps )
 	{
-		std::stringstream ss;
+		ss.str( "" );
+		ss.clear();
 
 		ss << "#version 330" << std::endl;
 		ss << std::endl;
diff --git a/code/nel/src/3d/driver/OpenGL3/driver_glsl_shader_generator.h b/code/nel/src/3d/driver/OpenGL3/driver_glsl_shader_generator.h
index 9246b6a5e..45d1eaa94 100644
--- a/code/nel/src/3d/driver/OpenGL3/driver_glsl_shader_generator.h
+++ b/code/nel/src/3d/driver/OpenGL3/driver_glsl_shader_generator.h
@@ -19,6 +19,7 @@
 #define GLSL_SHADER_GENERATOR
 
 #include <string>
+#include <sstream>
 
 namespace NL3D
 {
@@ -38,6 +39,7 @@ namespace NL3D
 		void setVBFormat( uint16 format ){ vbFormat = format; }
 
 	private:
+		std::stringstream ss;
 		uint16 vbFormat;
 		CMaterial const *material;
 	};