diff --git a/source/build/include/build.h b/source/build/include/build.h
index 98b7059cf..622957fea 100644
--- a/source/build/include/build.h
+++ b/source/build/include/build.h
@@ -1064,7 +1064,7 @@ int32_t wallvisible(int32_t const x, int32_t const y, int16_t const wallnum);
 int32_t   videoSetRenderMode(int32_t renderer);
 
 #ifdef USE_OPENGL
-void    renderSetRollAngle(int32_t rolla);
+void    renderSetRollAngle(float rolla);
 #endif
 
 //  pal: pass -1 to invalidate all palettes for the tile, or >=0 for a particular palette
diff --git a/source/build/src/engine.cpp b/source/build/src/engine.cpp
index 09de9bde9..36c9527bf 100644
--- a/source/build/src/engine.cpp
+++ b/source/build/src/engine.cpp
@@ -5465,8 +5465,8 @@ int32_t videoSetRenderMode(int32_t renderer)
 // setrollangle
 //
 #ifdef USE_OPENGL
-void renderSetRollAngle(int32_t rolla)
+void renderSetRollAngle(float rolla)
 {
-    gtang = (float)rolla * (fPI * (1.f/1024.f));
+    gtang = rolla * (fPI * (1.f/1024.f));
 }
 #endif