Rijad Zuzo
70 lines
1.9 KiB
GDScript
70 lines
1.9 KiB
GDScript
class_name KeyedRandom
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extends RefCounted
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const MASK_32 := 0xFFFFFFFF
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const UINT32_RANGE := 4294967296.0
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static func value_u32(
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world_seed: int, system_id: StringName, entity_id: StringName, occurrence: int
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) -> int:
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var hash_value := int(world_seed) & MASK_32
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hash_value = _mix_u32(hash_value ^ 0x9E3779B9)
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for byte in String(system_id).to_utf8_buffer():
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hash_value = _mix_u32(hash_value ^ int(byte))
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hash_value = _mix_u32(hash_value ^ 0x85EBCA6B)
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for byte in String(entity_id).to_utf8_buffer():
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hash_value = _mix_u32(hash_value ^ int(byte))
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hash_value = _mix_u32(hash_value ^ (occurrence & MASK_32))
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return hash_value
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static func value_float(
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world_seed: int, system_id: StringName, entity_id: StringName, occurrence: int
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) -> float:
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return float(value_u32(world_seed, system_id, entity_id, occurrence)) / UINT32_RANGE
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static func range_int(
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world_seed: int,
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system_id: StringName,
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entity_id: StringName,
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occurrence: int,
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minimum: int,
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maximum: int
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) -> int:
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if maximum < minimum:
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return minimum
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var width := maximum - minimum + 1
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return minimum + value_u32(world_seed, system_id, entity_id, occurrence) % width
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static func range_float(
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world_seed: int,
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system_id: StringName,
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entity_id: StringName,
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occurrence: int,
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minimum: float,
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maximum: float
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) -> float:
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if maximum <= minimum:
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return minimum
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return lerpf(minimum, maximum, value_float(world_seed, system_id, entity_id, occurrence))
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static func chance(
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world_seed: int,
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system_id: StringName,
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entity_id: StringName,
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occurrence: int,
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probability: float
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) -> bool:
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return value_float(world_seed, system_id, entity_id, occurrence) < clampf(probability, 0.0, 1.0)
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static func _mix_u32(value: int) -> int:
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var mixed := value & MASK_32
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mixed = ((mixed ^ (mixed >> 16)) * 0x7FEB352D) & MASK_32
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mixed = ((mixed ^ (mixed >> 15)) * 0x846CA68B) & MASK_32
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return (mixed ^ (mixed >> 16)) & MASK_32
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