Trying to clean up Process_Spacemove() to find issues with EVA slipping.

code/__defines/misc.dm

@@ -379,4 +379,9 @@
 #define CRAYON_DRAW_RUNE     "rune"
 #define CRAYON_DRAW_GRAFFITI "graffiti"
 #define CRAYON_DRAW_LETTER   "letter"
-#define CRAYON_DRAW_ARROW    "arrow"
+#define CRAYON_DRAW_ARROW    "arrow"
+
+// Enum for results of is_space_movement_permitted()
+#define SPACE_MOVE_SUPPORTED (-1)
+#define SPACE_MOVE_FORBIDDEN   0
+#define SPACE_MOVE_PERMITTED   1

code/_helpers/mobs.dm

@@ -40,7 +40,7 @@
 	var/user_loc = user.loc
 
 	var/drifting = 0
-	if(!user.Process_Spacemove(0) && user.inertia_dir)
+	if(user.is_space_movement_permitted() == SPACE_MOVE_FORBIDDEN && user.inertia_dir)
 		drifting = 1
 
 	var/target_loc = target.loc
@@ -101,7 +101,7 @@
 	var/atom/original_loc = user.loc
 
 	var/drifting = 0
-	if(!user.Process_Spacemove(0) && user.inertia_dir)
+	if(user.is_space_movement_permitted() == SPACE_MOVE_FORBIDDEN && user.inertia_dir)
 		drifting = 1
 
 	var/holding = user.get_active_held_item()

code/controllers/subsystems/spacedrift.dm

@@ -34,9 +34,9 @@ SUBSYSTEM_DEF(spacedrift)
 				return
 			continue
 
-		if (!AM.loc || AM.loc != AM.inertia_last_loc || AM.Process_Spacemove(0))
+		if (!AM.loc || AM.loc != AM.inertia_last_loc || AM.is_space_movement_permitted() != SPACE_MOVE_FORBIDDEN)
 			AM.inertia_dir = 0
-		
+
 		AM.inertia_ignore = null
 
 		if (!AM.inertia_dir)

code/datums/movement/mob.dm

@@ -62,21 +62,28 @@
 	return (MOVEMENT_PROCEED|MOVEMENT_HANDLED)
 
 /datum/movement_handler/mob/space
-	var/allow_move
+	var/last_space_move_result
+
+// Notes on space movement chain:
+// - owning mob calls MayMove() via normal movement handler chain
+// - MayMove() sets last_space_move_result based on is_space_movement_permitted() (checks for footing, magboots, etc)
+// - last_space_move_result is checked in DoMove() and passed to try_space_move() as a param, which returns TRUE/FALSE
+// - if the original move result was forbidden, or try_space_move() fails, the handler prevents movement.
+// - Otherwise it goes ahead and lets the mob move.
 
 // Space movement
 /datum/movement_handler/mob/space/DoMove(direction, mob/mover, is_external)
 	if(mob.has_gravity() || (IS_NOT_SELF(mover) && is_external))
 		return
-	if(!allow_move || !mob.space_do_move(allow_move, direction))
+	if(last_space_move_result == SPACE_MOVE_FORBIDDEN || !mob.try_space_move(last_space_move_result, direction))
 		return MOVEMENT_HANDLED
 
 /datum/movement_handler/mob/space/MayMove(mob/mover, is_external)
 	if(IS_NOT_SELF(mover) && is_external)
 		return MOVEMENT_PROCEED
 	if(!mob.has_gravity())
-		allow_move = mob.Process_Spacemove(1)
-		if(!allow_move)
+		last_space_move_result = mob.is_space_movement_permitted(allow_movement = TRUE)
+		if(last_space_move_result == SPACE_MOVE_FORBIDDEN)
 			return MOVEMENT_STOP
 	return MOVEMENT_PROCEED
 

code/game/atoms_movable.dm

@@ -46,7 +46,7 @@
 
 //call this proc to start space drifting
 /atom/movable/proc/space_drift(direction)//move this down
-	if(!loc || direction & (UP|DOWN) || Process_Spacemove(0))
+	if(!loc || direction & (UP|DOWN) || is_space_movement_permitted() != SPACE_MOVE_FORBIDDEN)
 		inertia_dir = 0
 		inertia_ignore = null
 		return 0
@@ -59,29 +59,22 @@
 	return 1
 
 //return 0 to space drift, 1 to stop, -1 for mobs to handle space slips
-/atom/movable/proc/Process_Spacemove(var/allow_movement)
+/atom/movable/proc/is_space_movement_permitted(allow_movement = FALSE)
 	if(!simulated)
-		return 1
-
+		return SPACE_MOVE_PERMITTED
 	if(has_gravity())
-		return 1
-
+		return SPACE_MOVE_PERMITTED
 	if(length(grabbed_by))
-		return 1
-
+		return SPACE_MOVE_PERMITTED
 	if(throwing)
-		return 1
-
+		return SPACE_MOVE_PERMITTED
 	if(anchored)
-		return 1
-
+		return SPACE_MOVE_PERMITTED
 	if(!isturf(loc))
-		return 1
-
+		return SPACE_MOVE_PERMITTED
 	if(locate(/obj/structure/lattice) in range(1, get_turf(src))) //Not realistic but makes pushing things in space easier
-		return -1
-
-	return 0
+		return SPACE_MOVE_SUPPORTED
+	return SPACE_MOVE_FORBIDDEN
 
 /atom/movable/attack_hand(mob/user)
 	// Unbuckle anything buckled to us.

code/modules/ZAS/Airflow.dm

@@ -51,7 +51,7 @@ Contains helper procs for airflow, called by /connection_group.
 	return FALSE
 
 /mob/living/human/handle_airflow_stun()
-	if(!slip_chance())
+	if(!get_eva_slip_prob())
 		to_chat(src, SPAN_NOTICE("Air suddenly rushes past you!"))
 		return FALSE
 	. = ..()

code/modules/mechs/equipment/utility.dm

@@ -603,17 +603,14 @@
 	QDEL_NULL(ion_trail)
 	return ..()
 
-/obj/item/mech_equipment/ionjets/proc/allowSpaceMove()
-	if (!active)
+/obj/item/mech_equipment/ionjets/proc/provides_thrust()
+	if(!active)
 		return FALSE
-
-	var/obj/item/cell/C = owner.get_cell()
-	if (istype(C))
-		if (C.checked_use(movement_power * CELLRATE))
+	var/obj/item/cell/cell = owner?.get_cell()
+	if(istype(cell))
+		if(cell.checked_use(movement_power * CELLRATE))
 			return TRUE
-		else
-			deactivate()
-
+		deactivate()
 	return FALSE
 
 /obj/item/mech_equipment/ionjets/attack_self(mob/user)

code/modules/mechs/mech_movement.dm

@@ -121,7 +121,7 @@
 
 // Space movement
 /datum/movement_handler/mob/space/exosuit/DoMove(direction, mob/mover, is_external)
-	if(!mob.has_gravity() && (!allow_move || (allow_move == -1 && mob.handle_spaceslipping())))
+	if(!mob.has_gravity() && (last_space_move_result == SPACE_MOVE_FORBIDDEN || (last_space_move_result == SPACE_MOVE_SUPPORTED && mob.handle_spaceslipping())))
 		return MOVEMENT_HANDLED
 	mob.inertia_dir = 0
 
@@ -130,39 +130,40 @@
 		return MOVEMENT_PROCEED
 
 	if(!mob.has_gravity())
-		allow_move = mob.Process_Spacemove(1)
-		if(!allow_move)
+		last_space_move_result = mob.is_space_movement_permitted(allow_movement = TRUE)
+		if(last_space_move_result == SPACE_MOVE_FORBIDDEN)
 			return MOVEMENT_STOP
 	return MOVEMENT_PROCEED
 
-/mob/living/exosuit/can_slip(magboots_only = FALSE) //mechs are always magbooting
-	return FALSE
+/mob/living/exosuit/has_non_slip_footing()
+	return TRUE
 
-/mob/living/exosuit/Process_Spacemove(allow_movement)
-	//Regardless of modules, emp prevents control
+/mob/living/exosuit/has_magnetised_footing()
+	return TRUE
 
+/mob/living/exosuit/is_space_movement_permitted(allow_movement = FALSE)
+	. = SPACE_MOVE_FORBIDDEN
+	anchored = FALSE
+	//Regardless of modules, emp prevents control
 	if(has_gravity() || throwing || !isturf(loc) || length(grabbed_by) || !can_slip(magboots_only = TRUE) || locate(/obj/structure/lattice) in range(1, get_turf(src)))
+		. =  SPACE_MOVE_PERMITTED
+	else
+		var/obj/item/mech_equipment/ionjets/J = hardpoints[HARDPOINT_BACK]
+		if(istype(J) && ((allow_movement || J.stabilizers) && J.provides_thrust()))
+			. = SPACE_MOVE_PERMITTED
+	if(. == SPACE_MOVE_PERMITTED)
 		anchored = TRUE
-		return TRUE
-
-	var/obj/item/mech_equipment/ionjets/J = hardpoints[HARDPOINT_BACK]
-	if(istype(J) && ((allow_movement || J.stabilizers) && J.allowSpaceMove()))
-		return TRUE
 
-	anchored = FALSE
-	return FALSE
-
-/mob/living/exosuit/space_do_move(allow_move)
-	if(allow_move == 1)
+/mob/living/exosuit/try_space_move(space_move_result, direction)
+	if(space_move_result == SPACE_MOVE_PERMITTED)
 		if(emp_damage >= EMP_MOVE_DISRUPT && prob(25))
 			var/obj/item/mech_equipment/ionjets/J = hardpoints[HARDPOINT_BACK]
-			if(istype(J) && J.allowSpaceMove())
+			if(istype(J) && J.provides_thrust())
 				to_chat(src, SPAN_WARNING("\The [J] misfire, drifting \the [src] off course!"))
 				SetMoveCooldown(15)	//2 seconds of random rando panic drifting
 				step(src, pick(global.alldirs))
-			return 0
-
-	. = ..()
+			return FALSE
+	return ..()
 
 /mob/living/exosuit/overmap_can_discard()
 	for(var/atom/movable/AM in contents)

code/modules/mob/living/human/human_movement.dm

@@ -65,33 +65,19 @@
 	. = ..()
 	. += species.strength
 
-/mob/living/human/space_do_move(var/allow_move, var/direction)
-	if(allow_move == 1)
+/mob/living/human/try_space_move(space_move_result, direction)
+	if(space_move_result == SPACE_MOVE_PERMITTED)
 		var/obj/item/tank/jetpack/thrust = get_jetpack()
 		if(thrust && thrust.on && prob(skill_fail_chance(SKILL_EVA, 10, SKILL_ADEPT)))
-			to_chat(src, "<span class='warning'>You fumble with [thrust] controls!</span>")
+			to_chat(src, SPAN_WARNING("You fumble with the controls of \the [thrust]!"))
 			if(prob(50))
 				thrust.toggle()
 			if(prob(50))
 				thrust.stabilization_on = 0
 			SetMoveCooldown(15)	//2 seconds of random rando panic drifting
 			step(src, pick(global.alldirs))
-			return 0
-
-	. = ..()
-
-/mob/living/human/slip_chance(var/prob_slip = 5)
-	if(!..())
-		return 0
-	//Check hands and mod slip
-	for(var/hand_slot in get_held_item_slots())
-		var/datum/inventory_slot/inv_slot = get_inventory_slot_datum(hand_slot)
-		var/obj/item/held = inv_slot?.get_equipped_item()
-		if(!held)
-			prob_slip -= 2
-		else if(held.w_class <= ITEM_SIZE_SMALL)
-			prob_slip -= 1
-	return prob_slip
+			return FALSE
+	return ..()
 
 /mob/living/human/Move()
 	. = ..()

code/modules/mob/living/silicon/robot/drone/drone.dm

@@ -241,10 +241,6 @@
 	if(amount && should_be_dead() && stat == DEAD && !QDELETED(src))
 		gib()
 
-//DRONE MOVEMENT.
-/mob/living/silicon/robot/drone/slip_chance(var/prob_slip)
-	return 0
-
 //CONSOLE PROCS
 /mob/living/silicon/robot/drone/proc/law_resync()
 

code/modules/mob/living/silicon/robot/flying/flying.dm

@@ -43,11 +43,11 @@
 	if(. && !gibbed)
 		stop_flying()
 
-/mob/living/silicon/robot/flying/Process_Spacemove()
-	return (pass_flags & PASS_FLAG_TABLE) || ..()
+/mob/living/silicon/robot/flying/is_space_movement_permitted(allow_movement = FALSE)
+	return (pass_flags & PASS_FLAG_TABLE) ? SPACE_MOVE_PERMITTED : ..()
 
 /mob/living/silicon/robot/flying/can_fall(var/anchor_bypass = FALSE, var/turf/location_override = loc)
-	return !Process_Spacemove()
+	return is_space_movement_permitted() == SPACE_MOVE_FORBIDDEN
 
 /mob/living/silicon/robot/flying/can_overcome_gravity()
-	return Process_Spacemove()
+	return is_space_movement_permitted() != SPACE_MOVE_FORBIDDEN

code/modules/mob/living/simple_animal/_simple_animal.dm

@@ -587,5 +587,5 @@ var/global/list/simplemob_icon_bitflag_cache = list()
 	if((. = ..()))
 		queue_icon_update()
 
-/mob/living/simple_animal/Process_Spacemove(allow_movement)
-	return skip_spacemove ? 1 : ..()
+/mob/living/simple_animal/is_space_movement_permitted(allow_movement = FALSE)
+	return skip_spacemove ? SPACE_MOVE_PERMITTED : ..()

code/modules/mob/mob.dm

@@ -1407,7 +1407,7 @@
 	if(istype(paw) && paw.is_usable())
 		return paw
 
-/mob/proc/get_solid_footing(turf_only = FALSE)
+/mob/proc/get_solid_footing()
 
 	if(!loc)
 		return src // this is a bit weird but we shouldn't slip in nullspace probably
@@ -1417,15 +1417,15 @@
 	if(!istype(my_turf))
 		return my_turf
 
-	if(!my_turf.is_open() && (my_turf.is_wall() || my_turf.is_floor()))
+	if(my_turf.is_wall() || my_turf.is_floor())
 		return my_turf
 
 	// Check for catwalks and lattices.
 	var/atom/platform = my_turf.get_supporting_platform() || (locate(/obj/structure/lattice) in my_turf)
 	if(platform)
 		return platform
 
-	// Check for magbootable nearby atoms.
+	// Check for supportable nearby atoms.
 	for(var/turf/neighbor in RANGE_TURFS(my_turf, 1))
 		if(neighbor == my_turf)
 			continue
@@ -1436,24 +1436,26 @@
 			return platform
 
 	// Find something we are grabbing onto for support.
-	if(!turf_only)
-		for(var/atom/movable/thing in range(1, my_turf))
-			if(thing == src || thing == inertia_ignore || !thing.simulated || thing == buckled)
+	for(var/atom/movable/thing in range(1, my_turf))
+		if(thing == src || thing == inertia_ignore || !thing.simulated || thing == buckled)
+			continue
+		if(isturf(thing))
+			continue // We checked turfs when using magboots above.
+		else if(ismob(thing))
+			var/mob/victim = thing
+			if(victim.buckled)
 				continue
-			if(ismob(thing))
-				var/mob/victim = thing
-				if(victim.buckled)
-					continue
-			if(!thing.CanPass(src))
-				if(thing.anchored)
-					return thing
-				var/is_being_grabbed = FALSE
-				for(var/obj/item/grab/grab in get_active_grabs())
-					if(thing == grab.affecting)
-						is_being_grabbed = TRUE
-						break
-				if(!is_being_grabbed)
-					. = thing
+		else if(thing.CanPass(src))
+			continue
+		if(thing.anchored)
+			return thing
+		var/is_being_grabbed = FALSE
+		for(var/obj/item/grab/grab in get_active_grabs())
+			if(thing == grab.affecting)
+				is_being_grabbed = TRUE
+				break
+		if(!is_being_grabbed)
+			. = thing
 
 /mob/proc/can_slip(magboots_only = FALSE)
 
@@ -1462,7 +1464,7 @@
 		return FALSE
 
 	// Quick basic checks.
-	if(!simulated || !isturf(loc) || buckled || current_posture?.prone || immune_to_floor_hazards())
+	if(!simulated || !isturf(loc) || buckled || current_posture?.prone || throwing)
 		return FALSE
 
 	// Species flag/proc check.
@@ -1472,8 +1474,8 @@
 	// Check footwear.
 	if(!magboots_only && has_non_slip_footing())
 		return FALSE
-	// We can't magnetise onto a friendly handholding from our buddy.
-	if(has_magnetised_footing() && get_solid_footing(turf_only = TRUE))
+
+	if((has_gravity() || has_magnetised_footing()) && get_solid_footing())
 		return FALSE
 
 	// Slip!