diff --git a/src/blitter/8bpp_simple.cpp b/src/blitter/8bpp_simple.cpp
--- a/src/blitter/8bpp_simple.cpp
+++ b/src/blitter/8bpp_simple.cpp
@@ -55,7 +55,7 @@ void Blitter_8bppSimple::Draw(Blitter::B
 	}
 }
 
-Sprite *Blitter_8bppSimple::Encode(SpriteLoader::Sprite *sprite, AllocatorProc *allocator)
+Sprite *Blitter_8bppSimple::Encode(const SpriteLoader::Sprite *sprite, AllocatorProc *allocator)
 {
 	Sprite *dest_sprite;
 	dest_sprite = (Sprite *)allocator(sizeof(*dest_sprite) + sprite->height * sprite->width);