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import type { SeededRNG } from '@hollowdark/rng/seeded'
import { LEAF_COLORS, LEAF_VARIANTS } from '@hollowdark/lib/leaves/variants'
import type { Leaf, SceneDimensions } from '@hollowdark/lib/leaves/types'
const MIN_SIZE = 18
const MAX_SIZE = 36
const MIN_ROT_SPEED = -35
const MAX_ROT_SPEED = 35
const MIN_SWAY_FREQ_HZ = 0.18
const MAX_SWAY_FREQ_HZ = 0.5
const FROM_RIGHT_PROBABILITY = 0.72
/**
* Create a fresh leaf entering the scene from the upwind edge. With
* `FROM_RIGHT_PROBABILITY`, leaves spawn off the right side at a random y
* above the ground; the rest drop in from above at a random x. This
* matches a horizontal-wind feel rather than vertical snowfall.
*/
export function spawnLeaf(id: number, scene: SceneDimensions, rng: SeededRNG): Leaf {
const variant = rng.pick(LEAF_VARIANTS)
const color = rng.pick(LEAF_COLORS)
const size = MIN_SIZE + rng.next() * (MAX_SIZE - MIN_SIZE)
const fromRight = rng.nextBool(FROM_RIGHT_PROBABILITY)
let x: number
let y: number
let vx: number
let vy: number
if (fromRight) {
x = scene.width + size
y = rng.next() * scene.groundY * 0.88
vx = -18 - rng.next() * 12
vy = 2 + rng.next() * 8
} else {
x = rng.next() * scene.width
y = -size - rng.next() * 40
vx = -4 + rng.next() * 4
vy = 12 + rng.next() * 10
}
return {
id,
variantId: variant.id,
color,
size,
x,
y,
vx,
vy,
rotation: rng.next() * 360,
rotationSpeed: MIN_ROT_SPEED + rng.next() * (MAX_ROT_SPEED - MIN_ROT_SPEED),
swayPhase: rng.next() * Math.PI * 2,
swayFrequency: MIN_SWAY_FREQ_HZ + rng.next() * (MAX_SWAY_FREQ_HZ - MIN_SWAY_FREQ_HZ),
settled: false
}
}
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