Make Darksight Great Again (#4626)

* Polaris port of darksight adjusting

* I really need to stop doing this, don't I?

code/modules/mob/living/life.dm

@@ -173,6 +173,7 @@
 	..()
 
 	handle_vision()
+	handle_darksight()
 	handle_hud_icons()
 
 	return 1
@@ -212,3 +213,27 @@
 		set_light(0)
 		return FALSE
 
+/mob/living/proc/handle_darksight()
+	var/darksightedness = min(see_in_dark/world.view,1.0)	//A ratio of how good your darksight is, from 'nada' to 'really darn good'
+	var/current = dsoverlay.alpha/255						//Our current adjustedness
+
+	var/brightness = 0.0 //We'll assume it's superdark if we can't find something else.
+
+	if(isturf(loc))
+		var/turf/T = loc //Will be true 99% of the time, thus avoiding the whole elif chain
+		brightness = T.get_lumcount()
+
+	//Snowflake treatment of potential locations
+	else if(istype(loc,/obj/mecha)) //I imagine there's like displays and junk in there. Use the lights!
+		brightness = 1
+	else if(istype(loc,/obj/item/weapon/holder)) //Poor carried teshari and whatnot should adjust appropriately
+		var/turf/T = get_turf(src)
+		brightness = T.get_lumcount()
+
+	var/darkness = 1-brightness					//Silly, I know, but 'alpha' and 'darkness' go the same direction on a number line
+	var/adjust_to = min(darkness,darksightedness)//Capped by how darksighted they are
+	var/distance = abs(current-adjust_to)		//Used for how long to animate for
+	if(distance < 0.01) return					//We're already all set
+
+	//world << "[src] in B:[round(brightness,0.1)] C:[round(current,0.1)] A2:[round(adjust_to,0.1)] D:[round(distance,0.01)] T:[round(distance*10 SECONDS,0.1)]"
+	animate(dsoverlay, alpha = (adjust_to*255), time = (distance*10 SECONDS))

code/modules/mob/living/living.dm

@@ -1,3 +1,20 @@
+/mob/living/New()
+	..()
+
+	//I'll just hang my coat up over here
+	dsoverlay = image('icons/mob/darksight.dmi',global_hud.darksight) //This is a secret overlay! Go look at the file, you'll see.
+	var/mutable_appearance/dsma = new(dsoverlay) //Changing like ten things, might as well.
+	dsma.alpha = 0
+	dsma.plane = PLANE_LIGHTING
+	dsma.layer = LIGHTING_LAYER + 0.1
+	dsma.blend_mode = BLEND_ADD
+	dsoverlay.appearance = dsma
+
+/mob/living/Destroy()
+	dsoverlay.loc = null //I'll take my coat with me
+	dsoverlay = null
+	return ..()
+
 //mob verbs are faster than object verbs. See mob/verb/examine.
 /mob/living/verb/pulled(atom/movable/AM as mob|obj in oview(1))
 	set name = "Pull"

code/modules/mob/living/living_defines.dm

@@ -47,6 +47,8 @@
 
 	var/evasion = 0 // Makes attacks harder to land.  Each number equals 15% more likely to miss.  Negative numbers increase hit chance.
 	var/force_max_speed = 0 // If 1, the mob runs extremely fast and cannot be slowed.
+  
+	var/image/dsoverlay = null //Overlay used for darksight eye adjustments
 
 	var/glow_toggle = 0					// If they're glowing!
 	var/glow_color = "#FFFFFF"			// The color they're glowing!

code/modules/mob/living/login.dm

@@ -6,4 +6,6 @@
 	mind.active = 1		//indicates that the mind is currently synced with a client
 	//If they're SSD, remove it so they can wake back up.
 	update_antag_icons(mind)
+	client.screen |= global_hud.darksight
+	client.images |= dsoverlay
 	return .

code/modules/mob/mob_planes.dm

@@ -12,6 +12,7 @@
 
 	//It'd be nice to lazy init these but some of them are important to just EXIST. Like without ghost planemaster, you can see ghosts. Go figure.
 	plane_masters[VIS_FULLBRIGHT] 	= new /obj/screen/plane_master/fullbright						//Lighting system (lighting_overlay objects)
+	plane_masters[VIS_LIGHTING] 	= new /obj/screen/plane_master/lighting							//Lighting system (but different!)
 	plane_masters[VIS_GHOSTS] 		= new /obj/screen/plane_master/ghosts							//Ghosts!
 	plane_masters[VIS_AI_EYE]		= new /obj/screen/plane_master{plane = PLANE_AI_EYE}			//AI Eye!
 
@@ -131,12 +132,17 @@
 //Lighting is weird and has matrix shenanigans. Think of this as turning on/off darkness.
 /obj/screen/plane_master/fullbright
 	plane = PLANE_LIGHTING
-	layer = LIGHTING_LAYER
+	layer = LIGHTING_LAYER+1
 	color = null //To break lighting when visible (this is sorta backwards)
-	alpha = 255 //Starts full opaque
-	invisibility = 101 //But invisible
+	alpha = 0 //Starts full opaque
+	invisibility = 101
 	invis_toggle = TRUE
 
+/obj/screen/plane_master/lighting
+	plane = PLANE_LIGHTING
+	blend_mode = BLEND_MULTIPLY
+	alpha = 255
+
 /////////////////
 //Ghosts has a special alpha level
 /obj/screen/plane_master/ghosts