Initial commit

src/physics/net.js

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+import * as THREE from 'three';
+import { NET, goalLineX } from '../../shared/net.js';
+import { CAT, KIND, makeTag, xyz } from './bridge.js';
+
+/**
+ * The goal frame: posts, crossbar, and a mesh back that stops the puck.
+ *
+ * Static bodies, because a net that moves is a rule (it comes off its moorings)
+ * rather than a feature, and not one worth having before there is a game.
+ *
+ * The back and sides are solid boxes rather than a real mesh. A puck that goes
+ * in should stay in and settle, and modelling twine is a lot of work to make a
+ * puck stop moving.
+ */
+export function createNet(physics, end) {
+  const { api, world } = physics;
+  const line = goalLineX(end);
+  const halfW = NET.width / 2;
+  const r = NET.postRadius;
+
+  const sd = api.b3DefaultShapeDef();
+  sd.baseMaterial.friction = 0.4;
+  // Posts ring; the back eats everything so the puck settles in the net.
+  sd.baseMaterial.restitution = 0.35;
+  sd.baseMaterial.userMaterialId = makeTag(KIND.RINK, 0xff, end > 0 ? 10 : 11);
+  sd.filter.categoryBits = CAT.RINK;
+  sd.filter.maskBits = 0xffffffffffffffffn;
+
+  const bodies = [];
+  const box = (x, y, z, hx, hy, hz, restitution = null) => {
+    const bd = api.b3DefaultBodyDef();
+    bd.position = xyz(x, y, z);
+    const b = api.b3CreateBody(world, bd);
+    if (restitution !== null) sd.baseMaterial.restitution = restitution;
+    api.b3CreateBoxShape(b, sd, hx, hy, hz);
+    sd.baseMaterial.restitution = 0.35;
+    bodies.push(b);
+    return b;
+  };
+
+  // Posts, on the line.
+  box(line, NET.height / 2, halfW, r, NET.height / 2, r);
+  box(line, NET.height / 2, -halfW, r, NET.height / 2, r);
+  // Crossbar.
+  box(line, NET.height, 0, r, r, halfW);
+  // Back and sides, deadened so the puck does not fire back out.
+  //
+  // The net extends *away* from centre ice, `line + end * depth`. Getting this
+  // sign backwards put the back panel a metre in front of the goal line — a
+  // solid wall across the mouth — and every shot in the game bounced off it
+  // before it could cross. Nothing ever scored, and the symptom looked like a
+  // goalie problem.
+  box(line + end * NET.depth, NET.height / 2, 0, 0.04, NET.height / 2, halfW, 0.02);
+  box(line + end * NET.depth * 0.5, NET.height / 2, halfW, NET.depth / 2, NET.height / 2, 0.03, 0.05);
+  box(line + end * NET.depth * 0.5, NET.height / 2, -halfW, NET.depth / 2, NET.height / 2, 0.03, 0.05);
+
+  return {
+    end,
+    bodies,
+    destroy() {
+      for (const b of bodies) api.b3DestroyBody(b);
+    },
+  };
+}
+
+/** The rendered net: frame tubes plus a translucent mesh bag. */
+export function buildNetMesh(scene, end) {
+  const line = goalLineX(end);
+  const halfW = NET.width / 2;
+  const group = new THREE.Group();
+  group.name = 'net:' + end;
+
+  const frame = new THREE.MeshStandardMaterial({ color: 0xc0332c, roughness: 0.45, metalness: 0.25 });
+  const mesh = new THREE.MeshStandardMaterial({
+    color: 0xf2f4f8,
+    roughness: 0.9,
+    transparent: true,
+    opacity: 0.28,
+    side: THREE.DoubleSide,
+    depthWrite: false,
+  });
+
+  const tube = (len, x, y, z, axis) => {
+    const g = new THREE.CylinderGeometry(NET.postRadius, NET.postRadius, len, 10);
+    const m = new THREE.Mesh(g, frame);
+    if (axis === 'z') m.rotation.x = Math.PI / 2;
+    if (axis === 'x') m.rotation.z = Math.PI / 2;
+    m.position.set(x, y, z);
+    m.castShadow = true;
+    group.add(m);
+  };
+  tube(NET.height, line, NET.height / 2, halfW, 'y');
+  tube(NET.height, line, NET.height / 2, -halfW, 'y');
+  tube(NET.width, line, NET.height, 0, 'z');
+  // Back frame, so the net reads as a box rather than as a doorway.
+  tube(NET.depth, line + end * NET.depth / 2, 0.06, halfW, 'x');
+  tube(NET.depth, line + end * NET.depth / 2, 0.06, -halfW, 'x');
+
+  const back = new THREE.Mesh(new THREE.PlaneGeometry(NET.width, NET.height), mesh);
+  back.position.set(line + end * NET.depth, NET.height / 2, 0);
+  back.rotation.y = Math.PI / 2;
+  group.add(back);
+  for (const s of [1, -1]) {
+    const side = new THREE.Mesh(new THREE.PlaneGeometry(NET.depth, NET.height), mesh);
+    side.position.set(line + end * NET.depth / 2, NET.height / 2, s * halfW);
+    group.add(side);
+  }
+  const top = new THREE.Mesh(new THREE.PlaneGeometry(NET.depth, NET.width), mesh);
+  top.rotation.x = -Math.PI / 2;
+  top.position.set(line + end * NET.depth / 2, NET.height, 0);
+  group.add(top);
+
+  // Crease paint.
+  const crease = new THREE.Mesh(
+    new THREE.CircleGeometry(NET.creaseRadius, 24, end > 0 ? -Math.PI / 2 : Math.PI / 2, Math.PI),
+    new THREE.MeshBasicMaterial({ color: 0x77b3e0, transparent: true, opacity: 0.45, depthWrite: false }),
+  );
+  crease.rotation.x = -Math.PI / 2;
+  crease.position.set(line, 0.004, 0);
+  group.add(crease);
+
+  scene.add(group);
+  return group;
+}