diff --git a/dlls/wined3d/cs.c b/dlls/wined3d/cs.c
index b3b6588ff9b..04e01da9e0a 100644
--- a/dlls/wined3d/cs.c
+++ b/dlls/wined3d/cs.c
@@ -2110,6 +2110,8 @@ void wined3d_cs_emit_blt_sub_resource(struct wined3d_cs *cs, struct wined3d_reso
     op->flags = flags;
     if (fx)
         op->fx = *fx;
+    else
+        memset(&op->fx, 0, sizeof(op->fx));
     op->filter = filter;
 
     wined3d_resource_acquire(dst_resource);