Vision flag tweaks (#2779)

Normalizes some vision flag operations & adds SEE_BLACKNESS to all mobs if the compiler supports it.
Shouldn't break 510 clients even if the server is 511 & using SEE_BLACKNESS.
Should fix some visual glitches with wall-mounted objects being visible when the wall they're on isn't visible.

code/__defines/misc.dm

@@ -361,3 +361,10 @@ Will print: "/mob/living/carbon/human/death" (you can optionally embed it in a s
 #define USE_FAIL_INCAPACITATED 5
 #define USE_FAIL_NOT_IN_USER 6
 #define USE_FAIL_IS_SILICON 7
+
+// 510 doesn't have this flag, so this shim will turn it into a no-op if it doesn't exist.
+#ifndef SEE_BLACKNESS
+#define SEE_BLACKNESS 0
+#endif 
+
+#define DEFAULT_SIGHT (SEE_SELF|SEE_BLACKNESS)

code/modules/mob/living/carbon/alien/life.dm

@@ -95,9 +95,7 @@
 		return//Returns if no client
 
 	if (stat == 2 || (XRAY in src.mutations))
-		sight |= SEE_TURFS
-		sight |= SEE_MOBS
-		sight |= SEE_OBJS
+		sight |= (SEE_TURFS|SEE_MOBS|SEE_OBJS)
 		see_in_dark = 8
 		see_invisible = SEE_INVISIBLE_LEVEL_TWO
 	else if (stat != 2 && is_ventcrawling == 0)

code/modules/mob/living/carbon/human/species/species.dm

@@ -67,7 +67,7 @@
 	var/radiation_mod = 1                    // Radiation modifier
 	var/flash_mod =     1                    // Stun from blindness modifier.
 	var/fall_mod =      1                    // Fall damage modifier, further modified by brute damage modifier
-	var/vision_flags = SEE_SELF              // Same flags as glasses.
+	var/vision_flags = DEFAULT_SIGHT              // Same flags as glasses.
 	var/list/breakcuffs = list()                      //used in resist.dm to check if they can break hand/leg cuffs
 
 	// Death vars.

code/modules/mob/living/carbon/human/species/station/machine_subspecies.dm

@@ -201,7 +201,7 @@
 	flags = NO_BREATHE | NO_SCAN | NO_BLOOD | NO_PAIN | NO_POISON
 	spawn_flags = IS_RESTRICTED
 	appearance_flags = HAS_HAIR_COLOR
-	vision_flags = SEE_SELF | SEE_MOBS
+	vision_flags = DEFAULT_SIGHT | SEE_MOBS
 
 	blood_color = "#1F181F"
 	flesh_color = "#575757"

code/modules/mob/living/carbon/human/species/station/resomi.dm

@@ -110,6 +110,6 @@
 
 /datum/species/resomi/get_vision_flags(var/mob/living/carbon/human/H)
 	if(!(H.sdisabilities & DEAF) && !H.ear_deaf)
-		return SEE_SELF|SEE_MOBS
+		return DEFAULT_SIGHT|SEE_MOBS
 	else
-		return SEE_SELF
+		return DEFAULT_SIGHT

code/modules/mob/living/carbon/human/species/xenomorphs/alien_species.dm

@@ -51,7 +51,7 @@
 	breath_type = null
 	poison_type = null
 
-	vision_flags = SEE_SELF|SEE_MOBS
+	vision_flags = DEFAULT_SIGHT | SEE_MOBS
 
 	has_organ = list(
 		"heart" =           /obj/item/organ/heart,

code/modules/mob/living/carbon/metroid/life.dm

@@ -10,7 +10,7 @@
 		handle_nutrition()
 
 		if(is_ventcrawling == 0) // Stops sight returning to normal if inside a vent
-			sight = SEE_SELF
+			sight = initial(sight)
 
 		if (!client)
 			handle_targets()

code/modules/mob/living/silicon/ai/life.dm

@@ -157,11 +157,9 @@
 		src.blind.screen_loc = ui_entire_screen
 		if (src.blind.invisibility != 0)
 			src.blind.invisibility = 0
-		src.sight = src.sight&~SEE_TURFS
-		src.sight = src.sight&~SEE_MOBS
-		src.sight = src.sight&~SEE_OBJS
-		src.see_in_dark = 0
-		src.see_invisible = SEE_INVISIBLE_LIVING
+		sight &= ~(SEE_TURFS | SEE_MOBS | SEE_OBJS)
+		see_in_dark = 0
+		see_invisible = SEE_INVISIBLE_LIVING
 	else
 		update_dead_sight()
 

code/modules/mob/living/simple_animal/friendly/mouse.dm

@@ -68,7 +68,7 @@
 				squeak_soft(0)
 
 			if(is_ventcrawling == 0)
-				sight = SEE_SELF // Returns mouse sight to normal when they leave a vent
+				sight = initial(sight) // Returns mouse sight to normal when they leave a vent
 
 			if (squeals < maxSqueals)
 				var/diff = world.time - last_squealgain

code/modules/mob/mob_defines.dm

@@ -3,6 +3,7 @@
 	layer = 4.0
 	animate_movement = 2
 	flags = PROXMOVE
+	sight = DEFAULT_SIGHT
 	var/datum/mind/mind
 
 	var/stat = 0 //Whether a mob is alive or dead. TODO: Move this to living - Nodrak