# 2D noise generator
abstract class Noise

	# Get the noise value at `x`, `y`
	#
	# The coordinates `x`, `y` can be floats of any size.
	#
	# Returns a value between or equal to `min` and `max`.
	fun [](x, y: Float): Float is abstract

	# Lowest possible value returned by `[]`
	#
	# Default at `0.0`.
	#
	# Require: `min < max`
	var min = 0.0 is writable

	# Highest possible value returned by `[]`
	#
	# Default at `1.0`.
	#
	# Require: `min < max`
	var max = 1.0 is writable

	# Distance between reference points of the noise
	#
	# Higher values will result in smoother noise and
	# lower values will result in steeper curves.
	#
	# Default at `1.0`.
	var period = 1.0 is writable

	# Amplitude of the values returned by `[]`
	fun amplitude: Float do return max - min

	# Set the desired amplitude of the values returned by `[]`
	#
	# Will only modify `max`, `min` stays the same.
	fun amplitude=(value: Float) do max = min + value

	# Frequency of this noise
	fun frequency: Float do return 1.0/period

	# Set the frequency if this noise
	fun frequency=(value: Float) do period = 1.0/value

	# Seed to the random number generator `gradient_vector`
	#
	# By default, `seed` has a random value created with `Int::rand`.
	var seed: Int = 19511359.rand is lazy, writable
end