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use crate::{
math::{interpolate, s_curve::cubic::Cubic},
noise_fns::NoiseFn,
};
use core::marker::PhantomData;
pub struct Select<T, Source1, Source2, Control, const DIM: usize>
where
Source1: NoiseFn<T, DIM>,
Source2: NoiseFn<T, DIM>,
Control: NoiseFn<T, DIM>,
{
pub source1: Source1,
pub source2: Source2,
pub control: Control,
pub bounds: (f64, f64),
pub falloff: f64,
phantom: PhantomData<T>,
}
impl<T, Source1, Source2, Control, const DIM: usize> Select<T, Source1, Source2, Control, DIM>
where
Source1: NoiseFn<T, DIM>,
Source2: NoiseFn<T, DIM>,
Control: NoiseFn<T, DIM>,
{
pub fn new(source1: Source1, source2: Source2, control: Control) -> Self {
Select {
source1,
source2,
control,
bounds: (0.0, 1.0),
falloff: 0.0,
phantom: PhantomData,
}
}
pub fn set_bounds(self, lower_bound: f64, upper_bound: f64) -> Self {
Select {
bounds: (lower_bound, upper_bound),
..self
}
}
pub fn set_falloff(self, falloff: f64) -> Self {
Select { falloff, ..self }
}
}
impl<T, Source1, Source2, Control, const DIM: usize> NoiseFn<T, DIM>
for Select<T, Source1, Source2, Control, DIM>
where
T: Copy,
Source1: NoiseFn<T, DIM>,
Source2: NoiseFn<T, DIM>,
Control: NoiseFn<T, DIM>,
{
fn get(&self, point: [T; DIM]) -> f64 {
let control_value = self.control.get(point);
let (lower, upper) = self.bounds;
if self.falloff > 0.0 {
match () {
_ if control_value < (lower - self.falloff) => self.source1.get(point),
_ if control_value < (lower + self.falloff) => {
let lower_curve = lower - self.falloff;
let upper_curve = lower + self.falloff;
let alpha =
((control_value - lower_curve) / (upper_curve - lower_curve)).map_cubic();
interpolate::linear(self.source1.get(point), self.source2.get(point), alpha)
}
_ if control_value < (upper - self.falloff) => self.source2.get(point),
_ if control_value < (upper + self.falloff) => {
let lower_curve = upper - self.falloff;
let upper_curve = upper + self.falloff;
let alpha =
((control_value - lower_curve) / (upper_curve - lower_curve)).map_cubic();
interpolate::linear(self.source2.get(point), self.source1.get(point), alpha)
}
_ => self.source1.get(point),
}
} else if control_value < lower || control_value > upper {
self.source1.get(point)
} else {
self.source2.get(point)
}
}
}