spreads and stacks!

systems/bullets/spawn_patterns/spawn_pattern_stacker.gd

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+@tool
+class_name SpawnPatternStacker
+extends BulletSpawnPattern
+## Spawns a pattern in a "stack". The pattern will be spawned multiple
+## times at once with a varying [code]bullet_speed[/code].
+
+
+## The subpattern to stack.
+@export var pattern: BulletSpawnPattern
+## The number of times to "stack" up the pattern.
+@export_range(1, 1, 1, "or_greater") var stack_count: int = 1
+## The minimum speed of the stacked patterns.
+@export var min_speed: float:
+	set(value):
+		if min_speed != value:
+			min_speed = value
+			max_speed = maxf(min_speed, max_speed)
+## The maximum speed of the stacked patterns.
+@export var max_speed: float:
+	set(value):
+		if max_speed != value:
+			max_speed = value
+			min_speed = minf(min_speed, max_speed)
+
+
+func _spawn_bullets(bullet_set: BulletSet, preset: BulletPreset) -> void:
+	for i in stack_count:
+		pattern.set(
+			&"bullet_speed",
+			remap(float(i), 0.0, float(stack_count - 1), min_speed, max_speed)
+		)
+		pattern.spawn_bullets(bullet_set, preset)