Client colo(u)r no longer uses Client.color, now coloring the render game plane instead (#81328)

## About The Pull Request

Rather than utilizing `client.color`, client color datums now apply
their colors to the render game plane.

This means 
1. The player's HUD is no longer affected by client colors. Being
colorblind (in game) no longer makes all hud elements grey as well, only
the world.
2. Overall, less harsh colors. 

## Why It's Good For The Game

1. The player's HUD, being an OOC concept, should remain unaffected by
stuff like glasses and blindness. This is how it worked in the past,
before plane cube (IIRC), but it was lost in the transition.
2. Overall just looks a lot better, IMO. 

Here's what meson goggles with glasses colors active looks like:

Before: 


![image](https://github.com/tgstation/tgstation/assets/51863163/081b69b2-e545-48f8-9016-071107b2c4c1)

After: 


![image](https://github.com/tgstation/tgstation/assets/51863163/8a823a82-3953-4889-9594-ccae87843c00)


## Changelog

🆑 Melbert
qol: Glasses colors should be a lot less harsh, and being blind no
longer also blinds your hud.
/🆑

code/__HELPERS/colors.dm

@@ -47,24 +47,24 @@
 	var/list/color = rgb2num(HTMLstring)
 	return rgb(255 - color[1], 255 - color[2], 255 - color[3])
 
-///Flash a color on the client
+///Flash a color on the passed mob
 /proc/flash_color(mob_or_client, flash_color="#960000", flash_time=20)
-	var/client/flashed_client
+	var/mob/flashed_mob
 	if(ismob(mob_or_client))
-		var/mob/client_mob = mob_or_client
-		if(client_mob.client)
-			flashed_client = client_mob.client
-		else
-			return
+		flashed_mob = mob_or_client
 	else if(istype(mob_or_client, /client))
-		flashed_client = mob_or_client
+		var/client/flashed_client = mob_or_client
+		flashed_mob = flashed_client.mob
 
-	if(!istype(flashed_client))
+	if(!istype(flashed_mob))
 		return
 
-	var/animate_color = flashed_client.color
-	flashed_client.color = flash_color
-	animate(flashed_client, color = animate_color, time = flash_time)
+	var/datum/client_colour/temp/temp_color = new(flashed_mob)
+	temp_color.colour = flash_color
+	temp_color.fade_in = flash_time * 0.25
+	temp_color.fade_out = flash_time * 0.25
+	QDEL_IN(temp_color, (flash_time * 0.5) + 1)
+	flashed_mob.add_client_colour(temp_color)
 
 /// Blends together two colors (passed as 3 or 4 length lists) using the screen blend mode
 /// Much like multiply, screen effects the brightness of the resulting color
@@ -103,4 +103,3 @@
 
 
 #define RANDOM_COLOUR (rgb(rand(0,255),rand(0,255),rand(0,255)))
-

code/_onclick/hud/fullscreen.dm

@@ -223,4 +223,3 @@
 	icon_state = "noise"
 	color = "#04a8d1"
 	alpha = 80
-

code/modules/client/client_colour.dm

@@ -38,35 +38,32 @@
 /datum/client_colour/Destroy()
 	if(!QDELETED(owner))
 		owner.client_colours -= src
-		if(fade_out)
-			owner.animate_client_colour(fade_out)
-		else
-			owner.update_client_colour()
+		owner.animate_client_colour(fade_out)
 	owner = null
 	return ..()
 
 ///Sets a new colour, then updates the owner's screen colour.
 /datum/client_colour/proc/update_colour(new_colour, anim_time, easing = 0)
 	colour = new_colour
-	if(anim_time)
-		owner.animate_client_colour(anim_time, easing)
-	else
-		owner.update_client_colour()
+	owner.animate_client_colour(anim_time, easing)
 
 /**
  * Adds an instance of colour_type to the mob's client_colours list
  * colour_type - a typepath (subtyped from /datum/client_colour)
  */
-/mob/proc/add_client_colour(colour_type)
-	if(!ispath(colour_type, /datum/client_colour) || QDELING(src))
+/mob/proc/add_client_colour(colour_type_or_datum)
+	if(QDELING(src))
 		return
-
-	var/datum/client_colour/colour = new colour_type(src)
-	BINARY_INSERT(colour, client_colours, /datum/client_colour, colour, priority, COMPARE_KEY)
-	if(colour.fade_in)
-		animate_client_colour(colour.fade_in)
+	var/datum/client_colour/colour
+	if(istype(colour_type_or_datum, /datum/client_colour))
+		colour = colour_type_or_datum
+	else if(ispath(colour_type_or_datum, /datum/client_colour))
+		colour = new colour_type_or_datum(src)
 	else
-		update_client_colour()
+		CRASH("Invalid colour type or datum for add_client_color: [colour_type_or_datum || "null"]")
+
+	BINARY_INSERT(colour, client_colours, /datum/client_colour, colour, priority, COMPARE_KEY)
+	animate_client_colour(colour.fade_in)
 	return colour
 
 /**
@@ -77,8 +74,7 @@
 	if(!ispath(colour_type, /datum/client_colour))
 		return
 
-	for(var/cc in client_colours)
-		var/datum/client_colour/colour = cc
+	for(var/datum/client_colour/colour as anything in client_colours)
 		if(colour.type == colour_type)
 			qdel(colour)
 			break
@@ -123,31 +119,49 @@
 	};\
 	target = _our_colour\
 
+#define CLIENT_COLOR_FILTER_KEY "fake_client_color"
 
 /**
  * Resets the mob's client.color to null, and then reapplies a new color based
  * on the client_colour datums it currently has.
  */
 /mob/proc/update_client_colour()
-	if(!client)
+	if(isnull(hud_used))
 		return
-	client.color = ""
-	if(!client_colours.len)
-		return
-	MIX_CLIENT_COLOUR(client.color)
+
+	var/new_color = ""
+	if(length(client_colours))
+		MIX_CLIENT_COLOUR(new_color)
+
+	for(var/atom/movable/screen/plane_master/game_plane as anything in hud_used.get_true_plane_masters(RENDER_PLANE_GAME))
+		if(new_color)
+			game_plane.add_filter(CLIENT_COLOR_FILTER_KEY, 2, color_matrix_filter(new_color))
+		else
+			game_plane.remove_filter(CLIENT_COLOR_FILTER_KEY)
 
 ///Works similarly to 'update_client_colour', but animated.
-/mob/proc/animate_client_colour(anim_time = 20, anim_easing = 0)
-	if(!client)
+/mob/proc/animate_client_colour(anim_time = 2 SECONDS, anim_easing = NONE)
+	if(anim_time <= 0)
+		return update_client_colour()
+	if(isnull(hud_used))
 		return
-	if(!client_colours.len)
-		animate(client, color = "", time = anim_time, easing = anim_easing)
-		return
-	MIX_CLIENT_COLOUR(var/anim_colour)
-	animate(client, color = anim_colour, time = anim_time, easing = anim_easing)
+
+	var/anim_color = ""
+	if(length(client_colours))
+		MIX_CLIENT_COLOUR(anim_color)
+
+	for(var/atom/movable/screen/plane_master/game_plane as anything in hud_used.get_true_plane_masters(RENDER_PLANE_GAME))
+		if(anim_color)
+			game_plane.add_filter(CLIENT_COLOR_FILTER_KEY, 2, color_matrix_filter())
+			game_plane.transition_filter(CLIENT_COLOR_FILTER_KEY, color_matrix_filter(anim_color), anim_time, anim_easing)
+		else
+			game_plane.transition_filter(CLIENT_COLOR_FILTER_KEY, color_matrix_filter(), anim_time, anim_easing)
+			// This leaves a blank color filter on the hud which is, fine I guess?
 
 #undef MIX_CLIENT_COLOUR
 
+#undef CLIENT_COLOR_FILTER_KEY
+
 /datum/client_colour/glass_colour
 	priority = PRIORITY_LOW
 
@@ -228,6 +242,9 @@
 	priority = PRIORITY_ABSOLUTE
 	colour = COLOR_RED
 
+/datum/client_colour/temp
+	priority = PRIORITY_HIGH
+
 #undef PRIORITY_ABSOLUTE
 #undef PRIORITY_HIGH
 #undef PRIORITY_NORMAL