midas-canvas/examplegame.js

function ExampleGame() {
	var game = null;
	var system = null;

	var box = null;
	var helloText = null;
	var worldText = null;
	var track = false;

	this.init = function(systemObject, canvas) {
		game = this;
		system = systemObject;
		track = false;
		box = {position: {x: 10, y: 10}, width: 50, height: 50, velocity: {x: 1, y: 1}};
		helloText = {text: "Hello", width: 100, height: 100, offset: {x:0, y:0}};
		worldText = {text: "World", width: 100, height: 100, offset: {x:0, y:0}};
	};

	this.updateDelta = function(canvas, delta){
		this.update(canvas);
		if(!track) {
			box.position.x += box.velocity.x * delta;
			box.position.y += box.velocity.y * delta;

			if(box.position.x < 0) {
				box.velocity.x *= -1;
				box.position.x = 0;
			}
			if(box.position.y < 0) {
				box.velocity.y *= -1;
				box.position.y = 0;
			}

			if(box.position.x + box.width > canvas.width) {
				box.velocity.x *= -1;
				box.position.x = canvas.width - box.width;
			}
			if(box.position.y + box.height > canvas.height) {
				box.velocity.y *= -1;
				box.position.y = canvas.height - box.height;
			}
		}

		helloText.offset.x = box.position.x + (box.width / 2);
		helloText.offset.y = box.position.y + 16;

		worldText.offset.x = box.position.x + (box.width / 2);
		worldText.offset.y = box.position.y + 32;
	};
	this.update = function(canvas) {
		
	};

	this.draw = function(context) {
		context.fillStyle = "#33DD33";
		context.strokeStyle = "#33DD33";
		context.beginPath();
		context.fillRect(box.position.x, box.position.y, box.width, box.height);
		context.rect(box.position.x, box.position.y, box.width, box.height);
		context.stroke();

		context.font = "16px sans-serif";
		context.textAlign = "center";
		context.fillStyle = "#3333DD";
		var helloMetrics = context.measureText("Hello");
		var worldMetrics = context.measureText("World");
		helloText.width = helloMetrics.width;
		worldText.width = worldMetrics.width;
		context.fillText(helloText.text, helloText.offset.x, helloText.offset.y);
		context.fillText(worldText.text, worldText.offset.x, worldText.offset.y);
	};

	this.mouseMove = function(canvas, x, y) {
		if(track) {
			box.position.x = x - box.width / 2;
			box.position.y = y - box.height / 2;
		}
	};

	this.mouseClick = function(canvas, button, x, y) {
		track = !track;
		if(track) {
			box.position.x = x - box.width / 2;
			box.position.y = y - box.height / 2;
		}
	};

	this.contextMenu = function(canvas, event) {

	};
}