diff --git a/progs/glsl/bump.c b/progs/glsl/bump.c
index 87669aec736..50a0900f1c7 100644
--- a/progs/glsl/bump.c
+++ b/progs/glsl/bump.c
@@ -36,7 +36,7 @@ static GLint win = 0;
 
 static GLfloat xRot = 20.0f, yRot = 0.0f, zRot = 0.0f;
 
-static GLuint tangentAttrib;
+static GLint tangentAttrib;
 
 static GLboolean Anim = GL_FALSE;