splat-ecs/lib/game-loop.js

"use strict";

var timeAccumulator = require("time-accumulator");

module.exports = function(entities, simulation, simulationStepTime, renderer, context) {
	var run = timeAccumulator(simulationStepTime);
	var timeDelta = require("./absolute-to-relative")();
	var running = true;

	// run simulation the first time, because not enough time will have elapsed
	simulation.run(entities, 0);

	var remainingDebugTime;
	window.timeSystems = function(total) {
		simulation.resetTimings();
		renderer.resetTimings();
		remainingDebugTime = total;
	};
	function trackDebugTiming(elapsed) {
		if (remainingDebugTime === undefined) {
			return;
		}
		remainingDebugTime -= elapsed;
		if (remainingDebugTime > 0) {
			return;
		}
		remainingDebugTime = undefined;

		var timings = simulation.timings().concat(renderer.timings());
		var total = timings.map(function(timing) {
			return timing.time;
		}).reduce(function(a, b) {
			return a + b;
		});
		timings.sort(function(a, b) {
			return b.time - a.time;
		}).forEach(function(timing) {
			timing.percent = timing.time / total;
		});
		console.table(timings);
	}

	function render(time) {
		if (!running) {
			return;
		}

		var elapsed = timeDelta(time);
		run(elapsed, function(elapsed) {
			simulation.run(entities, elapsed);
		});

		context.save();
		renderer.run(entities, context, elapsed);
		context.restore();

		trackDebugTiming(elapsed);

		if (running) {
			window.requestAnimationFrame(render);
		}
	}
	window.requestAnimationFrame(render);

	return function() {
		running = false;
	};
};