Merge pull request #6700 from Citadel-Station-13/upstream-merge-37399

[MIRROR] Use spritesheets to reduce time spent sending PNG assets by 90+%

code/__DEFINES/misc.dm

@@ -445,3 +445,9 @@ GLOBAL_LIST_INIT(ghost_others_options, list(GHOST_OTHERS_SIMPLE, GHOST_OTHERS_DE
 #define NO_INIT_PARAMETER "no-init"
 
 #define EGG_LAYING_MESSAGES list("lays an egg.","squats down and croons.","begins making a huge racket.","begins clucking raucously.")
+
+// Used by PDA and cartridge code to reduce repetitiveness of spritesheets
+#define PDAIMG(what) {"<span class="pda16x16 [#what]"></span>"}
+
+//Filters
+#define AMBIENT_OCCLUSION filter(type="drop_shadow", x=0, y=-2, size=4, border=4, color="#04080FAA")