straywild/world/water_surface_motion.gd

114 lines
3.1 KiB
GDScript

class_name WaterSurfaceMotion
extends MeshInstance3D
const DEFAULT_AMPLITUDE: float = 0.055
const DEFAULT_CYCLE_SECONDS: float = 7.0
const DEFAULT_SECONDARY_SWELL: float = 0.18
const DEFAULT_PHASE_OFFSET: float = 0.0
const STABLE_SURFACE_HEIGHT_OFFSET_PARAMETER: StringName = (
&"stable_surface_height_offset"
)
@export_range(0.0, 0.2, 0.005, "suffix:m") var amplitude: float = (
DEFAULT_AMPLITUDE
)
@export_range(1.0, 30.0, 0.1, "suffix:s") var cycle_seconds: float = (
DEFAULT_CYCLE_SECONDS
)
@export_range(0.0, 0.5, 0.01) var secondary_swell: float = (
DEFAULT_SECONDARY_SWELL
)
@export_range(0.0, TAU, 0.01, "radians") var phase_offset: float = 0.0
var _base_height: float
var _motion_strength_multiplier: float = 1.0
func _ready() -> void:
_base_height = position.y
_apply_height_offset(0.0)
set_process(amplitude > 0.0)
func _process(_delta: float) -> void:
_apply_height_offset(
calculate_height_offset(
_current_time_seconds(),
get_effective_amplitude(),
cycle_seconds,
secondary_swell,
phase_offset,
)
)
func set_motion_enabled(enabled: bool) -> void:
set_process(enabled and amplitude > 0.0)
if not enabled:
_apply_height_offset(0.0)
func set_motion_strength_multiplier(multiplier: float) -> void:
_motion_strength_multiplier = maxf(multiplier, 0.0)
if _motion_strength_multiplier <= 0.0:
_apply_height_offset(0.0)
func get_motion_strength_multiplier() -> float:
return _motion_strength_multiplier
func get_effective_amplitude() -> float:
return amplitude * _motion_strength_multiplier
func _apply_height_offset(height_offset: float) -> void:
position.y = _base_height + height_offset
# Headless worlds have no visible shoreline to correct. Skip the visual
# material update there and keep dedicated/headless worlds presentation-free.
if DisplayServer.get_name() == "headless":
return
# The surface can still bob visually, but all shoreline shader thresholds
# should remain at the authored waterline. Only the active ocean uses this
# moving material, so publishing the offset on that material is sufficient.
var shader_material := material_override as ShaderMaterial
if shader_material == null:
shader_material = get_active_material(0) as ShaderMaterial
if shader_material != null:
shader_material.set_shader_parameter(
STABLE_SURFACE_HEIGHT_OFFSET_PARAMETER,
-height_offset
)
static func get_default_height_offset() -> float:
return calculate_height_offset(
_current_time_seconds(),
DEFAULT_AMPLITUDE,
DEFAULT_CYCLE_SECONDS,
DEFAULT_SECONDARY_SWELL,
DEFAULT_PHASE_OFFSET,
)
static func calculate_height_offset(
time_seconds: float,
motion_amplitude: float,
motion_cycle_seconds: float,
motion_secondary_swell: float,
motion_phase_offset: float,
) -> float:
var safe_cycle := maxf(motion_cycle_seconds, 0.001)
var phase := (
fposmod(time_seconds, safe_cycle) / safe_cycle * TAU
+ motion_phase_offset
)
var swell := (
sin(phase)
+ sin(phase * 2.0 + 1.1) * motion_secondary_swell
) / (1.0 + motion_secondary_swell)
return swell * motion_amplitude
static func _current_time_seconds() -> float:
return float(Time.get_ticks_msec()) * 0.001