From bb369af72fe68dffc93ff823c30d014ceeab2221 Mon Sep 17 00:00:00 2001
From: Vi3trice <80771500+Vi3trice@users.noreply.github.com>
Date: Sat, 4 Oct 2025 15:35:08 -0400
Subject: [PATCH] Cache light colors in computers (#30590)

* Remember the lights

* Update computer.dm
---
 code/game/machinery/computer/computer.dm | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/code/game/machinery/computer/computer.dm b/code/game/machinery/computer/computer.dm
index fac6352d1b9..27800ac71e4 100644
--- a/code/game/machinery/computer/computer.dm
+++ b/code/game/machinery/computer/computer.dm
@@ -17,6 +17,8 @@
 	var/flickering = FALSE
 	/// Are we forcing the icon to be represented in a no-power state?
 	var/force_no_power_icon_state = FALSE
+	/// Cached list of colors associated with overlays
+	var/list/cached_emissive_color = list()
 
 /obj/machinery/computer/Initialize(mapload)
 	. = ..()
@@ -86,12 +88,13 @@
 		underlays += emissive_appearance(icon, "[icon_keyboard]_lightmask")
 
 	if(!(stat & BROKEN))
-		// Get the average color of the computer screen so it can be used as a tinted glow
-		// Shamelessly stolen from /tg/'s /datum/component/customizable_reagent_holder.
-		var/icon/emissive_avg_screen_color = new(icon, overlay_state)
-		emissive_avg_screen_color.Scale(1, 1)
-		var/screen_emissive_color = copytext(emissive_avg_screen_color.GetPixel(1, 1), 1, 8) // remove opacity
-		set_light(light_range_on, light_power_on, screen_emissive_color)
+		if(!cached_emissive_color[overlay_state])
+			// Get the average color of the computer screen so it can be used as a tinted glow
+			// Shamelessly stolen from /tg/'s /datum/component/customizable_reagent_holder.
+			var/icon/emissive_avg_screen_color = new(icon, overlay_state)
+			emissive_avg_screen_color.Scale(1, 1)
+			cached_emissive_color[overlay_state] = copytext(emissive_avg_screen_color.GetPixel(1, 1), 1, 8) // remove opacity
+		set_light(light_range_on, light_power_on, cached_emissive_color[overlay_state])
 
 /obj/machinery/computer/power_change()
 	. = ..() //we don't check parent return due to this also being contigent on the BROKEN stat flag