diff --git a/src/r_data.c b/src/r_data.c
index 48facb25..b168fd60 100644
--- a/src/r_data.c
+++ b/src/r_data.c
@@ -65,7 +65,7 @@ typedef struct
 typedef struct
 {
   char       name[8];
-  boolean    masked;
+  int        masked;
   short      width;
   short      height;
   char       pad[4];       // unused in Doom but might be used in Boom Phase 2