gistfile1.js

length = Math.max(canvas.width, canvas.height);
// Make sure the rays are bigger than the canvas

midx = canvas.width / 2, midy = canvas.height / 2;
// Get the mid point of our canvas

var d = 12;
// how many rays (or divisions)
for(i = 0;i < d;i++){
	angle = (Math.PI * 2 / d) * i;
	// 360 degrees is Math.PI * 2:
	// we're getting that divided by
	// divisions times loop interations
	context.moveTo(midx, midy);
	// Move to the middle of the canvas
	c1 = getXY(midx, midy, length, angle + d / 100);
	// Calculate the first co-ordinates
	context.lineTo(c1.x, c1.y);
	// Line from the middle to the first co-ordinates
	c2 = getXY(midx, midy, length, angle - d / 100);
	// Calculate the second co-ordinates
	context.lineTo(c2.x, c2.y);
	// Line to the second co-ordinates
	context.lineTo(midx, midy);
	// Line back to the middle
	context.fill();
};