Et-Setera

Despite traveling soccer season heating up, I have managed to make some real progress on destroyable terrain since hitting a wall in my last post. Ground tiles are now implemented and working quite well. In this first video, you can see the individual tiles being marked as the digger works its way through the ground.

Once it was clear that the correct tiles were being found and that the image alteration was working, the next step was to calculate the correct alterations to match the digger’s location as shown as red in this video.

Finally, terrain destruction was completed by clearing those same image pixels to transparent resulting in the following.

Clearing to Transparent

Clearing the image pixels to transparent turned out to be a bit trickier than I had guessed it would be. The default paint “transfer mode” is such that painting with a transparent color results in no changes to the image. In order to erase the image to transparency, the transfer mode needs to be changed like the following:

		// Set up a paint that can be used to clear pixels from a ground tile
		Paint paint = new Paint();
		paint.setColor(Color.TRANSPARENT);
		paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
		paint.setStrokeWidth(1);

With the paint set to CLEAR mode, the Android graphics functions can then be used to alter the image pixels.

New Things Uncovered

I recently picked up a Motorola Xoom that I have also thrown AndPingus on to. It showed me that there are a couple of pretty interesting issues with the current implementation:

• Proper Speed Scaling
  The digger handler doesn’t properly account for clock speed and digging happens way too fast on something as fast as the Xoom.
• Extra Large Screens
  Recent Android versions introduced extra large screen support. Unfortunately, AndPingus isn’t correctly utilizing the screen size yet. I’m still trying to understand how to properly handle older devices at the same time as the extra large screen size.

Planned Source Release

I’ve decided that I’m going to go ahead and release a couple of utility pieces of the AndPingus source code as open source for others to take advantage of. My plan is to make available the following pieces:

• QuadTree
  I created a QuadTree implementation for searching the sprites. At the moment, because of the ground tiles, that code is not being used. However, it seems like it may useful to others.
• Drawable Texture Support
  This is the underlying implementation of the destroyable terrain implementation in AndPingus.

As I mentioned before, I’m getting busy with soccer coaching these days, so I can’t offer a specific timeframe for the release. Before I can make that happen, I need to decide on appropriate licensing and hosting options. In addition, I need to do at least a bit of cleanup before unleashing it to others. Stay tuned to this blog for more information when it becomes available.