silphius/app/ecs/ecs.test.js

import {expect, test} from 'vitest';

import Arbitrary from './arbitrary.js';
import Ecs from './ecs.js';
import Schema from './schema.js';
import System from './system.js';

function wrapSpecification(name, specification) {
  return class Component extends Arbitrary {
    static componentName = name;
    static schema = new Schema({
      type: 'object',
      properties: specification,
    });
  };
}

const Empty = wrapSpecification('Empty', {});

const Name = wrapSpecification('Name', {
  name: {type: 'string'},
});

const Position = wrapSpecification('Position', {
  x: {type: 'int32', defaultValue: 32},
  y: {type: 'int32'},
  z: {type: 'int32'},
});

test('activates and deactivates systems at runtime', () => {
  let oneCount = 0;
  let twoCount = 0;
  const ecs = new Ecs({
    Systems: {
      OneSystem: class extends System {
        tick() {
          oneCount += 1;
        }
      },
      TwoSystem: class extends System {
        tick() {
          twoCount += 1;
        }
      },
    },
  });
  ecs.tick();
  expect(oneCount)
    .to.equal(0);
  expect(twoCount)
    .to.equal(0);
  ecs.system('OneSystem').active = true;
  ecs.tick();
  expect(oneCount)
    .to.equal(1);
  ecs.system('TwoSystem').active = true;
  ecs.tick();
  expect(oneCount)
    .to.equal(2);
  expect(twoCount)
    .to.equal(1);
  ecs.system('OneSystem').active = false;
  ecs.tick();
  expect(oneCount)
    .to.equal(2);
  expect(twoCount)
    .to.equal(2);
});

test('creates entities with components', () => {
  const ecs = new Ecs({Components: {Empty, Position}});
  const entity = ecs.create({Empty: {}, Position: {y: 128}});
  expect(JSON.stringify(ecs.get(entity)))
    .to.deep.equal(JSON.stringify({Empty: {}, Position: {y: 128}}));
});

test("removes entities' components", () => {
  const ecs = new Ecs({Components: {Empty, Position}});
  const entity = ecs.create({Empty: {}, Position: {y: 128}});
  ecs.remove(entity, ['Position']);
  expect(JSON.stringify(ecs.get(entity)))
    .to.deep.equal(JSON.stringify({Empty: {}}));
});

test('gets entities', () => {
  const ecs = new Ecs({Components: {Empty, Position}});
  const entity = ecs.create({Empty: {}, Position: {y: 128}});
  expect(JSON.stringify(ecs.get(entity)))
    .to.deep.equal(JSON.stringify({Empty: {}, Position: {y: 128}}));
});

test('destroys entities', () => {
  const ecs = new Ecs({Components: {Empty, Position}});
  const entity = ecs.create({Empty: {}, Position: {y: 128}});
  expect(JSON.stringify(ecs.get(entity)))
    .to.deep.equal(JSON.stringify({Empty: {}, Position: {y: 128}}));
  expect(ecs.get(entity))
    .to.not.be.undefined;
  ecs.destroyAll();
  expect(ecs.get(entity))
    .to.be.undefined;
  expect(() => {
    ecs.destroy(entity);
  })
    .to.throw();
});

test('inserts components into entities', () => {
  const ecs = new Ecs({Components: {Empty, Position}});
  const entity = ecs.create({Empty: {}});
  ecs.insert(entity, {Position: {y: 128}});
  expect(JSON.stringify(ecs.get(entity)))
    .to.deep.equal(JSON.stringify({Empty: {}, Position: {y: 128}}));
  ecs.insert(entity, {Position: {y: 64}});
  expect(JSON.stringify(ecs.get(entity)))
    .to.deep.equal(JSON.stringify({Empty: {}, Position: {y: 64}}));
});

test('ticks systems', () => {
  const Momentum = wrapSpecification('Momentum', {
    x: {type: 'int32'},
    y: {type: 'int32'},
    z: {type: 'int32'},
  });
  const ecs = new Ecs({
    Components: {Momentum, Position},
    Systems: {
      Physics: class Physics extends System {

        static queries() {
          return {
            default: ['Position', 'Momentum'],
          };
        }

        tick(elapsed) {
          for (const [position, momentum] of this.select('default')) {
            position.x += momentum.x * elapsed;
            position.y += momentum.y * elapsed;
            position.z += momentum.z * elapsed;
          }
        }

      },
    },
  });
  ecs.system('Physics').active = true;
  const entity = ecs.create({Momentum: {}, Position: {y: 128}});
  const position = JSON.stringify(ecs.get(entity).Position);
  ecs.tick(1);
  expect(JSON.stringify(ecs.get(entity).Position))
    .to.deep.equal(position);
  ecs.get(1).Momentum.y = 30;
  ecs.tick(1);
  expect(JSON.stringify(ecs.get(entity).Position))
    .to.deep.equal(JSON.stringify({y: 128 + 30}));
});

test('creates many entities when ticking systems', () => {
  const ecs = new Ecs({
    Systems: {
      Spawn: class extends System {
        tick() {
          this.createManyEntities(Array.from({length: 5}).map(() => []));
        }
      },
    },
  });
  ecs.system('Spawn').active = true;
  ecs.create();
  expect(ecs.get(5))
    .to.be.undefined;
  ecs.tick(1);
  expect(ecs.get(5))
    .to.not.be.undefined;
});

test('creates entities when ticking systems', () => {
  const ecs = new Ecs({
    Systems: {
      Spawn: class extends System {
        tick() {
          this.createEntity();
        }
      },
    },
  });
  ecs.system('Spawn').active = true;
  ecs.create();
  expect(ecs.get(2))
    .to.be.undefined;
  ecs.tick(1);
  expect(ecs.get(2))
    .to.not.be.undefined;
});

test('schedules entities to be deleted when ticking systems', () => {
  let entity;
  const ecs = new Ecs({
    Systems: {
      Despawn: class extends System {
        finalize() {
          entity = ecs.get(1);
        }
        tick() {
          this.destroyEntity(1);
        }
      },
    },
  });
  ecs.system('Despawn').active = true;
  ecs.create();
  ecs.tick(1);
  expect(entity)
    .to.not.be.undefined;
  expect(ecs.get(1))
    .to.be.undefined;
});

test('adds components to and remove components from entities when ticking systems', () => {
  let addLength, removeLength;
  const ecs = new Ecs({
    Components: {Foo: wrapSpecification('Foo', {bar: {type: 'uint8'}})},
    Systems: {
      AddComponent: class extends System {
        static queries() {
          return {
            default: ['Foo'],
          };
        }
        tick() {
          this.insertComponents(1, {Foo: {}});
        }
        finalize() {
          addLength = Array.from(this.select('default')).length;
        }
      },
      RemoveComponent: class extends System {
        static queries() {
          return {
            default: ['Foo'],
          };
        }
        tick() {
          this.removeComponents(1, ['Foo']);
        }
        finalize() {
          removeLength = Array.from(this.select('default')).length;
        }
      },
    },
  });
  ecs.system('AddComponent').active = true;
  ecs.create();
  ecs.tick(1);
  expect(addLength)
    .to.equal(1);
  expect(ecs.get(1).Foo)
    .to.not.be.undefined;
  ecs.system('AddComponent').active = false;
  ecs.system('RemoveComponent').active = true;
  ecs.tick(1);
  expect(removeLength)
    .to.equal(0);
  expect(ecs.get(1).Foo)
    .to.be.undefined;
});

test('generates coalesced diffs for entity creation', () => {
  const ecs = new Ecs();
  let entity;
  entity = ecs.create();
  expect(ecs.diff)
    .to.deep.equal({[entity]: {}});
});

test('generates diffs for adding and removing components', () => {
  const ecs = new Ecs({Components: {Position}});
  let entity;
  entity = ecs.create();
  ecs.setClean();
  ecs.insert(entity, {Position: {x: 64}});
  expect(ecs.diff)
    .to.deep.equal({[entity]: {Position: {x: 64}}});
  ecs.setClean();
  expect(ecs.diff)
    .to.deep.equal({});
  ecs.remove(entity, ['Position']);
  expect(ecs.diff)
    .to.deep.equal({[entity]: {Position: false}});
});

test('generates diffs for empty components', () => {
  const ecs = new Ecs({Components: {Empty}});
  let entity;
  entity = ecs.create({Empty: {}});
  expect(ecs.diff)
    .to.deep.equal({[entity]: {Empty: {}}});
  ecs.setClean();
  ecs.remove(entity, ['Empty']);
  expect(ecs.diff)
    .to.deep.equal({[entity]: {Empty: false}});
});

test('generates diffs for entity mutations', () => {
  const ecs = new Ecs({Components: {Position}});
  let entity;
  entity = ecs.create({Position: {}});
  ecs.setClean();
  ecs.get(entity).Position.x = 128;
  expect(ecs.diff)
    .to.deep.equal({[entity]: {Position: {x: 128}}});
  ecs.setClean();
  expect(ecs.diff)
    .to.deep.equal({});
});

test('generates coalesced diffs for components', () => {
  const ecs = new Ecs({Components: {Position}});
  let entity;
  entity = ecs.create({Position});
  ecs.remove(entity, ['Position']);
  expect(ecs.diff)
    .to.deep.equal({[entity]: {Position: false}});
  ecs.insert(entity, {Position: {}});
  expect(ecs.diff)
    .to.deep.equal({[entity]: {Position: {}}});
});

test('generates coalesced diffs for mutations', () => {
  const ecs = new Ecs({Components: {Position}});
  let entity;
  entity = ecs.create({Position});
  ecs.setClean();
  ecs.get(entity).Position.x = 128;
  ecs.get(entity).Position.x = 256;
  ecs.get(entity).Position.x = 512;
  expect(ecs.diff)
    .to.deep.equal({[entity]: {Position: {x: 512}}});
});

test('generates diffs for deletions', () => {
  const ecs = new Ecs();
  let entity;
  entity = ecs.create();
  ecs.setClean();
  ecs.destroy(entity);
  expect(ecs.diff)
    .to.deep.equal({[entity]: false});
});

test('applies creation patches', () => {
  const ecs = new Ecs({Components: {Position}});
  ecs.apply({16: {Position: {x: 64}}});
  expect(Array.from(ecs.entities).length)
    .to.equal(1);
  expect(ecs.get(16).Position.x)
    .to.equal(64);
});

test('applies update patches', () => {
  const ecs = new Ecs({Components: {Position}});
  ecs.createSpecific(16, {Position: {x: 64}});
  ecs.apply({16: {Position: {x: 128}}});
  expect(Array.from(ecs.entities).length)
    .to.equal(1);
  expect(ecs.get(16).Position.x)
    .to.equal(128);
});

test('applies entity deletion patches', () => {
  const ecs = new Ecs({Components: {Position}});
  ecs.createSpecific(16, {Position: {x: 64}});
  ecs.apply({16: false});
  expect(Array.from(ecs.entities).length)
    .to.equal(0);
});

test('applies component deletion patches', () => {
  const ecs = new Ecs({Components: {Empty, Position}});
  ecs.createSpecific(16, {Empty: {}, Position: {x: 64}});
  expect(ecs.get(16).constructor.componentNames)
    .to.deep.equal(['Empty', 'Position']);
  ecs.apply({16: {Empty: false}});
  expect(ecs.get(16).constructor.componentNames)
    .to.deep.equal(['Position']);
});

test('calculates entity size', () => {
  const ecs = new Ecs({Components: {Empty, Position}});
  ecs.createSpecific(1, {Empty: {}, Position: {}});
  // ID + # of components + Empty + Position + x + y + z
  // 4  + 2               + 2 + 4 + 2 + 4    + 4 + 4 + 4 = 30
  expect(ecs.get(1).size())
    .to.equal(30);
});

test('serializes and deserializes', () => {
  const ecs = new Ecs({Components: {Empty, Name, Position}});
  ecs.createSpecific(1, {Empty: {}, Position: {x: 64}});
  ecs.createSpecific(16, {Name: {name: 'foobar'}, Position: {x: 128}});
  expect(ecs.toJSON())
    .to.deep.equal({
      entities: {
        1: {Empty: {}, Position: {x: 64}},
        16: {Name: {name: 'foobar'}, Position: {x: 128}},
      },
      systems: [],
    });
  const view = Ecs.serialize(ecs);
  const deserialized = Ecs.deserialize(
    new Ecs({Components: {Empty, Name, Position}}),
    view,
  );
  expect(Array.from(deserialized.entities).length)
    .to.equal(2);
  expect(deserialized.get(1).constructor.componentNames)
    .to.deep.equal(['Empty', 'Position']);
  expect(deserialized.get(16).constructor.componentNames)
    .to.deep.equal(['Name', 'Position']);
  expect(JSON.stringify(deserialized.get(1)))
    .to.equal(JSON.stringify({Empty: {}, Position: {x: 64}}))
  expect(JSON.stringify(deserialized.get(1).Position))
    .to.equal(JSON.stringify({x: 64}));
  expect(JSON.stringify(deserialized.get(16).Position))
    .to.equal(JSON.stringify({x: 128}));
  expect(deserialized.get(16).Name.name)
    .to.equal('foobar');
});

test('deserializes from compatible ECS', () => {
  const ecs = new Ecs({Components: {Empty, Name, Position}});
  ecs.createSpecific(1, {Empty: {}, Position: {x: 64}});
  ecs.createSpecific(16, {Name: {name: 'foobar'}, Position: {x: 128}});
  const view = Ecs.serialize(ecs);
  const deserialized = Ecs.deserialize(
    new Ecs({Components: {Empty, Name}}),
    view,
  );
  expect(deserialized.get(1).toJSON())
    .to.deep.equal({Empty: {}});
  expect(deserialized.get(16).toJSON())
    .to.deep.equal({Name: {name: 'foobar'}});
});