Zones

Zones are used to demarcate 3D regions of space within scenes. There are various types of zones, each of which have different behaviours when Twinsen enters or interacts with them:

teleport zones transport Twinsen to a different scene when entered
camera zones change the camera position and angle when entered
sceneric zones define areas of the scene used for "is actor in zone?" queries in scripts
fragment zones define an area of the scene's terrain that can be dynamically shown or hidden
bonus zones dispense items when interacted with
text zones are used to implement signs and say dialogue when interacted with
ladder zones provide vertical movement
conveyor zones move actors which stand within them
spike zones deal damaged when entered (floor spikes, traps, etc)
rail zones are used to control minecart movement

All zones are cuboid in shape.

Zone File Format

Zones are stored as part of the scene containing the zone:

{
    i32         x0
    i32         y0
    i32         z0
    i32         x1
    i32         y1
    i32         z1
    i32         info0
    i32         info1
    i32         info2
    i32         info3
    i32         info4
    i32         info5
    i32         info6
    i32         info7
    i16         type
    i16         value
}

x0, y0, z0: first corner defining the zone cuboid
x1, y1, z1: opposite corner defining the zone cuboid
info0..7: zone parameters; interpretation depends on the zone type
type: the type of zone
value: zone parameter; interpretation depends on the zone type

Zone type	Name
0	Teleport
1	Camera
2	Sceneric
3	Fragment
4	Bonus
5	Text
6	Ladder
7	Conveyor
8	Spike
9	Rail

The documentation below for each of the zone types describes how the flags are interpreted, as loaded from the scene. The LBA engine modifies some of these values at run-time in order to avoid allocating additional memory; these run-time uses and modifications are not documented here.

Teleport zones

Parameter	Description
param	Destination scene
info0	Destination x
info1	Destination y
info2	Destination z
info3	Destination angle
info4	Zone scripting ID
info5	Door flags: bit 0 - for exterior scenes, don’t activate zone until Twinsen collides with the door
info6	Collision flags: bit 0 - don’t adjust Twinsen to fix collisions
info7	Enable flags: bit 0 - zone is enabled

Teleport zones can be enabled or disabled from script by using the SET_TELEPORT_ZONE opcode.

Camera zones

Parameter	Description
param	Zone scripting ID
info0	Camera x
info1	Camera y
info2	Camera z
info3	Camera alpha angle
info4	Camera beta angle
info5	Camera gamma angle
info6	View distance
info7	Enable flags: bit 0 - zone is enabled

Camera zones can be enabled or disabled from script by using the SET_CAMERA opcode.

Sceneric zones

Parameter	Description
param	Zone scripting ID
info0	-unused-
info1	-unused-
info2	-unused-
info3	-unused-
info4	-unused-
info5	-unused-
info6	-unused-
info7	-unused-

Sceneric zones can be used from scripts by checking whether an actor is within them by using the ZONE and ZONE_OBJ conditions.

Fragment zones

Parameter	Description
param	Zone scripting ID
info0	Fragment number
info1	-unused-
info2	Enable flags: bit 0 - zone is enabled
info3	-unused-
info4	-unused-
info5	-unused-
info6	-unused-
info7	-unused-

Fragment zones can be enabled or disabled from script by using the SET_FRAGMENT opcode.

Bonus zones

Parameter	Description
param	-unused-
info0	Bonus type
info1	Bonus quantity
info2	-unused-
info3	-unused-
info4	-unused-
info5	-unused-
info6	-unused-
info7	-unused-

Bonus zones are not scriptable.

Text zones

Parameter	Description
param	Message ID
info0	Text colour
info1	Associated camera zone (zero for none)
info2	Direction
info3	-unused-
info4	-unused-
info5	-unused-
info6	-unused-
info7	-unused-

Text zones are not scriptable.

The direction values seem appropriate for use as a bitmask but the LBA engine checks for equality, not a bit test, so each text zone can only face a single direction. Double-sided signs would require two sign zones, one on each side.

Zone direction	Description
1	Sign faces North
2	Sign faces South
4	Sign faces East
8	Sign faces West

Ladder zones

Parameter	Description
param	Zone scripting ID
info0	Enabled
info1	-unused-
info2	-unused-
info3	-unused-
info4	-unused-
info5	-unused-
info6	-unused-
info7	-unused-

Ladder zones can be enabled or disabled from script using the SET_LADDER_ZONE opcode. Their enabled state can be queried using the LADDER condition.

Conveyor zones

Parameter	Description
param	Zone scripting ID
info0	-unused-
info1	Enabled
info2	Direction
info3	-unused-
info4	-unused-
info5	-unused-
info6	-unused-
info7	-unused-

Conveyor zones can be enabled or disabled from script using the SET_CONVEYOR_ZONE opcode.

The direction values seem appropriate for use as a bitmask but the LBA engine checks for equality, not a bit test.

Zone direction	Description
1	Conveyor travels North
2	Conveyor travels South
4	Conveyor travels East
8	Conveyor travels West

Spike zones

Parameter	Description
param	Zone scripting ID
info0	-unused-
info1	Damage
info2	Rearm time
info3	-unused-
info4	-unused-
info5	-unused-
info6	-unused-
info7	-unused-

The damage of spike zones can be controlled from script using the SET_SPIKE_ZONE opcode. Setting the damage to zero will disable the spike zone; setting it to a non-zero value will enable it.

Rail zones

Parameter	Description
param	Zone scripting ID
info0	Enabled
info1	Switch set
info2	-unused-
info3	-unused-
info4	-unused-
info5	-unused-
info6	-unused-
info7	-unused-