One thing that has been missing from the game is a proper sense of movement as the ship gathers way. The sea already has some crude pulsating squares that represent the waves so you can tell you are moving, but there was little sense of speed. What I needed was a way of rendering the bow wave and wake produced by the ship as it cuts through the water.

My first attempt was to make some animated sprites and draw them onto the ship surface. The effect was quite nice, but it looked a bit fake. I’m not a great artist, and I couldn’t get it to look convincing enough without jarring with the simple visual style used for the rest of the ship. Moreover, it was hard to deal with cases where the ship was moving slowly. My solution was the slow the animation down to match the speed of the ship, but this ruined the effect of the animation.

Then I found a much neater solution. As the ship moves, I draw circles onto the sea starting at the bow of the ship. The circle doesn’t move with the ship, but it expands quickly to create the effect of the bow pushing water aside. If I draw them quick enough, they give the illusion of one wavy trail of frothy water. The faster the ship goes, the more often these are created, and the brighter they are. As you accelerate, the bow wave gets more and more noticeable, improving the sense of speed. The colour also gradually dims to the sea colour before disappearing. I’m pretty pleased with the result, and because there are no sprites to manipulate it takes up very little CPU overhead.