bee
69 lines
2.7 KiB
GDScript
69 lines
2.7 KiB
GDScript
class_name FloatingBody
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extends RigidBody3D
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## Buoyant rigid body. Add Marker3D children as float probes (e.g. the four
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## corners of a hull); each probe pushes up in proportion to how deep it is
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## below the ocean surface, which makes the body bob and tilt with the waves.
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## Upward acceleration as a multiple of gravity when fully submerged.
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## > 1.0 floats, < 1.0 sinks. Higher rides higher in the water.
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@export var buoyancy := 2.0
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## Probe depth (in meters) at which buoyant force reaches full strength.
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@export var full_force_depth := 0.4
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## Linear drag applied while in the water.
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@export var water_drag := 1.5
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## Rotational drag applied while in the water.
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@export var water_angular_drag := 1.0
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## Probes generated across the hull footprint if no Marker3D children exist.
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@export var probe_extents := Vector3(0.35, 0.0, 0.9) # half-width, height, half-length
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@export var probe_grid := Vector2i(2, 4) # columns (x), rows (z)
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@export var probe_damping := 4.0
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var _probe_offsets: Array[Vector3] = [] # local space
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var _ocean: Ocean
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var _probes: Array[Marker3D] = []
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var _gravity: float = ProjectSettings.get_setting("physics/3d/default_gravity")
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var submerged_ratio := 0.0
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func _ready() -> void:
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_ocean = get_tree().get_first_node_in_group("ocean") as Ocean
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# manual markers take priority if present...
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for child in get_children():
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if child is Marker3D:
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_probe_offsets.append(child.position)
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# ...otherwise generate a grid over the hull footprint
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if _probe_offsets.is_empty():
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for col in probe_grid.x:
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for row in probe_grid.y:
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_probe_offsets.append(Vector3(
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lerpf(-probe_extents.x, probe_extents.x, col / float(probe_grid.x - 1)),
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probe_extents.y,
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lerpf(-probe_extents.z, probe_extents.z, row / float(probe_grid.y - 1))))
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func _physics_process(_delta: float) -> void:
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if _ocean == null or _probe_offsets.is_empty():
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return
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submerged_ratio = 0.0
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for offset in _probe_offsets:
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var pos := global_transform * offset
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var depth := _ocean.get_wave_height(pos) - pos.y
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if depth > 0.0:
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var factor := clampf(depth / full_force_depth, 0.0, 1.0)
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submerged_ratio += factor / _probe_offsets.size()
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var force := Vector3.UP * _gravity * mass * buoyancy * factor / _probe_offsets.size()
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apply_force(force, pos - global_position)
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var r := pos - global_position
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# velocity of this specific point on the hull (body motion + rotation)
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var point_velocity := linear_velocity + angular_velocity.cross(r)
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var damp := Vector3.UP * -point_velocity.y * probe_damping * factor * mass / _probe_offsets.size()
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apply_force(force + damp, r)
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if submerged_ratio > 0.0:
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apply_central_force(-linear_velocity * water_drag * mass * submerged_ratio)
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apply_torque(-angular_velocity * water_angular_drag * mass * submerged_ratio)
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