diff --git a/shaders/gbuffer.frag.glsl b/shaders/gbuffer.frag.glsl
index 42be0d7..9545128 100644
--- a/shaders/gbuffer.frag.glsl
+++ b/shaders/gbuffer.frag.glsl
@@ -10,7 +10,7 @@ layout (location = 3) out vec4 outSpecular;
 uniform float materialNs;
 
 // variables used for picking
-uniform unsigned int object_identifier;
+uniform int object_identifier;
 #ifdef INSTANCED
 flat in int instanceId;
 #endif