diff --git a/src/matfx.cpp b/src/matfx.cpp
index 3771ebf..7a60fd3 100644
--- a/src/matfx.cpp
+++ b/src/matfx.cpp
@@ -134,7 +134,7 @@ MatFX::setEffects(Material *mat, uint32 type)
 }
 
 uint32
-MatFX::getEffects(Material *m)
+MatFX::getEffects(const Material *m)
 {
 	MatFX *fx = *PLUGINOFFSET(MatFX*, m, matFXGlobals.materialOffset);
 	if(fx)
diff --git a/src/rwplugins.h b/src/rwplugins.h
index af23303..62165ba 100644
--- a/src/rwplugins.h
+++ b/src/rwplugins.h
@@ -128,7 +128,7 @@ struct MatFX
 	uint32 type;
 
 	static void setEffects(Material *m, uint32 flags);
-	static uint32 getEffects(Material *m);
+	static uint32 getEffects(const Material *m);
 	static MatFX *get(Material *m);
 	int32 getEffectIndex(uint32 type);
 	// Bump