SM: Fix pressure bonus system (#62255)

* SM: Fix pressure bonus system

Fixes #62124 (Pressure wasn't actually doing anything)

> This is a multiplier meant to be used at low pressures.
> The lower the pressure the higher the multiplier.
> This is to encourage low pressure setups and so cold setups.
> At higher pressures (from around 100 kpa and up) it will max to 1

Current behavior is what follows.
As pressure drops, the multiplier remained at 1 until it dropped to 5.96kPa.
It then very marginally increased until it reaches x1.17 at 0kPa.

This commit introduces a system that solves the constants for the equation
based on human readable parameters, and sets provisional parameters for it. Also makes behavior better match the stated intent.

You can varedit the parameters to see the real effects of changes, just be
sure to proc call update_constants().

Constants default to what amounts to 0 so it fails loud (I WANT TO HEAR SUFFERING -Lemon)

code/modules/power/supermatter/supermatter.dm

@@ -179,6 +179,27 @@ GLOBAL_DATUM(main_supermatter_engine, /obj/machinery/power/supermatter_crystal)
 	///How much hallucination should we produce per unit of power?
 	var/hallucination_power = 0.1
 
+	///Pressure bonus constants
+	///If the SM is operating in sufficiently low pressure, increase power output.
+	///This needs both a small amount of gas and a strong cooling system to keep temperature low in a low heat capacity environment.
+
+	///These constants are used to derive the values in the pressure bonus equation from human-meaningful values
+	///If you're varediting these, call update_constants() to update the derived values
+
+	///What is the maximum multiplier reachable from having low pressure?
+	var/pressure_bonus_max_multiplier = 0.5
+	///At what environmental pressure, in kPa, should we start giving a pressure bonus?
+	var/pressure_bonus_max_pressure = 100
+	///How steeply angled is the pressure bonus curve? Higher values means more of the bonus is available at higher pressures.
+	///Note that very low values can keep the bonus very close to 1 until it's nearly a vaccuum. Higher values can introduce diminishing returns on lower pressure.
+	var/pressure_bonus_curve_angle = 1.8
+
+	///These values are calculated from the above in update_constants() and immediately overwritten
+	///The default values will always result in a no-op 1x modifier, in case something breaks.
+	var/pressure_bonus_derived_constant = 1
+	var/pressure_bonus_derived_steepness = 0
+
+
 	///Our internal radio
 	var/obj/item/radio/radio
 	///The key our internal radio uses
@@ -253,6 +274,8 @@ GLOBAL_DATUM(main_supermatter_engine, /obj/machinery/power/supermatter_crystal)
 	if (!moveable)
 		move_resist = MOVE_FORCE_OVERPOWERING // Avoid being moved by statues or other memes
 
+	update_constants()
+
 /obj/machinery/power/supermatter_crystal/Destroy()
 	investigate_log("has been destroyed.", INVESTIGATE_SUPERMATTER)
 	SSair.stop_processing_machine(src)
@@ -265,6 +288,10 @@ GLOBAL_DATUM(main_supermatter_engine, /obj/machinery/power/supermatter_crystal)
 		QDEL_NULL(psyOverlay)
 	return ..()
 
+/obj/machinery/power/supermatter_crystal/proc/update_constants()
+	pressure_bonus_derived_steepness = (1 - 1 / pressure_bonus_max_multiplier) / (pressure_bonus_max_pressure ** pressure_bonus_curve_angle)
+	pressure_bonus_derived_constant = 1 / pressure_bonus_max_multiplier - pressure_bonus_derived_steepness
+
 /obj/machinery/power/supermatter_crystal/examine(mob/user)
 	. = ..()
 	var/immune = HAS_TRAIT(user, TRAIT_SUPERMATTER_MADNESS_IMMUNE) || (user.mind && HAS_TRAIT(user.mind, TRAIT_SUPERMATTER_MADNESS_IMMUNE))
@@ -652,7 +679,7 @@ GLOBAL_DATUM(main_supermatter_engine, /obj/machinery/power/supermatter_crystal)
 			//(1 + (tritRad + pluoxDampen * bzDampen * o2Rad * plasmaRad / (10 - bzrads))) * freonbonus
 			playsound(src, 'sound/weapons/emitter2.ogg', 70, TRUE)
 			var/power_multiplier = max(0, (1 + (power_transmission_bonus / (10 - (gas_comp[/datum/gas/bz] * BZ_RADIOACTIVITY_MODIFIER)))) * freonbonus)// RadModBZ(500%)
-			var/pressure_multiplier = max((1 / ((env_pressure ** 1.5) + 5.5) * 0.01) + 0.8, 1)
+			var/pressure_multiplier = max((1 / ((env_pressure ** pressure_bonus_curve_angle) + 1) * pressure_bonus_derived_steepness) + pressure_bonus_derived_constant, 1)
 			var/co2_power_increase = max(gas_comp[/datum/gas/carbon_dioxide] * 2, 1)
 			supermatter_zap(
 				zapstart = src,