root
92 lines
2.0 KiB
Go
92 lines
2.0 KiB
Go
package world
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import (
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"wh/config"
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"wh/fixed"
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"wh/rng"
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)
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// Ore identifies a raw material.
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type Ore int
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const (
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Iron Ore = iota
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Nickel
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Ice
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Platinum
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NumOre
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)
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func (o Ore) String() string {
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return [...]string{"iron", "nickel", "ice", "platinum"}[o]
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}
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type Asteroid struct {
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ID int64
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Orbit Orbit
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Ore [NumOre]int64 // remaining kilograms of each ore
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}
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func (a *Asteroid) TotalOre() int64 {
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var t int64
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for _, v := range a.Ore {
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t += v
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}
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return t
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}
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// Station is the dropoff point, on a circular orbit in the ecliptic plane.
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type Station struct {
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Orbit Orbit
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}
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// Stream labels keep independent generation phases from sharing randomness.
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const (
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labelBelt = iota + 1
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labelStation
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)
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// Generate builds the asteroid field and station from the config seed.
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func Generate(cfg config.Config) ([]Asteroid, Station) {
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r := rng.Derive(cfg.Seed, labelBelt)
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asts := make([]Asteroid, cfg.AsteroidCount)
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for i := range asts {
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a := r.FixedRange(cfg.BeltInner, cfg.BeltOuter)
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asts[i] = Asteroid{
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ID: int64(i + 1),
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Orbit: Orbit{
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A: a,
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Period: PeriodFor(a, cfg.OrbitSpeed),
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M0: r.FixedRange(0, fixed.TwoPi),
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Node: r.FixedRange(0, fixed.TwoPi),
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// Bias inclination low (squared uniform).
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Inc: r.Fixed().Mul(r.Fixed()).Mul(cfg.MaxInclination),
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},
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}
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// Each asteroid has a total mass and a random mix of ores.
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total := int64(50_000) + int64(r.Intn(950_000))
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var weights [NumOre]uint64
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var wsum uint64
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for o := range weights {
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weights[o] = r.Intn(100) + 1
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wsum += weights[o]
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}
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// Platinum is rare: only a fifth of asteroids carry much of it.
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if r.Intn(5) != 0 {
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wsum -= weights[Platinum]
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weights[Platinum] = 0
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}
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for o := range weights {
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asts[i].Ore[o] = total * int64(weights[o]) / int64(wsum)
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}
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}
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sr := rng.Derive(cfg.Seed, labelStation)
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a := (cfg.BeltInner + cfg.BeltOuter).DivInt(2)
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st := Station{Orbit: Orbit{
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A: a,
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Period: PeriodFor(a, cfg.OrbitSpeed),
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M0: sr.FixedRange(0, fixed.TwoPi),
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}}
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return asts, st
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}
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