+ int bd_color_b; // BD engine C64-style cave color (border)
+ int bd_color_0; // BD engine C64-style cave color (background)
+ int bd_color_1; // BD engine C64-style cave color (sand)
+ int bd_color_2; // BD engine C64-style cave color (steel wall)
+ int bd_color_3; // BD engine C64-style cave color (wall)
+ int bd_color_4; // BD engine C64-style cave color (amoeba)
+ int bd_color_5; // BD engine C64-style cave color (slime)