97 lines
3.6 KiB
TypeScript
97 lines
3.6 KiB
TypeScript
import { Terrain, type Terrain as Ground } from "../../../engine/world/Terrain"
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import { Mesh, type Mesh as Geometry } from "../../../engine/scene/Mesh"
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import type { Material } from "../../../engine/render/Material"
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import type { ActorDefinition } from "../../../engine/scene/Actor"
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import { Mob, type MobState } from "../Mob"
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import { ellipsoid, nextRand, wanderHeading } from "./mobkit"
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// Everything about the robin: round red-breasted bird that mostly hops like a frog
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// but now and then takes a short powered flight to a new perch.
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export type Robin = ActorDefinition<MobState, Ground>
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export namespace Robin {
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export function create(material: Material): Robin {
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const mesh = Mesh.create()
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build(mesh)
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return {
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prototype: {
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groups: [{ mesh, material }],
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radius: 0.5,
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minY: -0.5,
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maxY: 1,
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},
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update,
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transform: Mob.transform,
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collider: (state) => Mob.collider(state, 0.45, 0.55, state.grounded),
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}
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}
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}
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const LEASH = 6
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const REST_MIN = 0.5
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const REST_SPAN = 1.3
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const HOP_SPEED = 1.4
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const HOP_IMPULSE = 2.6
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/** Fraction of a robin's moves that are a flight rather than a ground hop. */
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const FLY_CHANCE = 0.35
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const FLY_SPEED = 4.5
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const FLY_IMPULSE = 3.5
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const CRUISE = 0.8
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const GRAVITY = 14
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function build(mesh: Geometry): void {
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// Round European robin: plump brown body, an orange-red breast bulging on the
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// front, a round brown head with two dark eyes + a small dark beak, short tail.
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// UVs: robin texture is brown (left), orange breast (mid), dark eye/beak (right).
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ellipsoid(mesh, 0, 0.26, 0, 0.26, 0.26, 0.3, 6, 4, 0, 0.38, 0, 1) // body (brown)
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ellipsoid(mesh, 0, 0.18, 0.17, 0.22, 0.22, 0.16, 5, 4, 0.42, 0.68, 0, 1) // breast (orange)
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ellipsoid(mesh, 0, 0.48, 0.14, 0.18, 0.18, 0.18, 5, 4, 0, 0.38, 0, 1) // head (brown)
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ellipsoid(mesh, 0.09, 0.52, 0.26, 0.03, 0.03, 0.03, 3, 2, 0.85, 0.99, 0, 1) // eye
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ellipsoid(mesh, -0.09, 0.52, 0.26, 0.03, 0.03, 0.03, 3, 2, 0.85, 0.99, 0, 1) // eye
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ellipsoid(mesh, 0, 0.47, 0.35, 0.03, 0.025, 0.09, 3, 2, 0.85, 0.99, 0, 1) // beak (dark)
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ellipsoid(mesh, 0, 0.26, -0.32, 0.09, 0.05, 0.16, 4, 2, 0, 0.38, 0, 1) // tail (brown)
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}
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function update(mob: MobState, dt: number, terrain: Ground): void {
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if (mob.grounded) {
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mob.timer -= dt
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mob.position.y = Terrain.height(terrain, mob.position.x, mob.position.z)
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if (mob.timer > 0) {
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return
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}
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// Decide the next move: usually a short ground hop, sometimes a longer powered
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// flight -- higher + faster off the mark, then a flat glide (see the cruise
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// branch below) before settling onto a new perch.
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mob.heading = wanderHeading(mob, LEASH, 1)
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const fly = nextRand(mob) < FLY_CHANCE
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const speed = fly ? FLY_SPEED : HOP_SPEED
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mob.vx = Math.sin(mob.heading) * speed
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mob.vz = Math.cos(mob.heading) * speed
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mob.vy = fly ? FLY_IMPULSE : HOP_IMPULSE
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mob.phase = fly ? CRUISE : 0
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mob.grounded = false
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return
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}
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if (mob.phase > 0) {
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// In flight: bleed vertical speed toward level so it glides roughly flat (a bird
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// crossing the clearing), not a lob; gravity resumes once the cruise ends.
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mob.phase -= dt
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mob.vy += (0 - mob.vy) * Math.min(1, dt * 6)
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} else {
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mob.vy -= GRAVITY * dt
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}
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mob.position.x += mob.vx * dt
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mob.position.y += mob.vy * dt
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mob.position.z += mob.vz * dt
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const ground = Terrain.height(terrain, mob.position.x, mob.position.z)
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if (mob.position.y <= ground && mob.vy < 0) {
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mob.position.y = ground
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mob.vx = 0
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mob.vy = 0
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mob.vz = 0
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mob.phase = 0
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mob.grounded = true
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mob.timer = REST_MIN + nextRand(mob) * REST_SPAN
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}
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}
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