How to implement a Worms style destructible terrain in XNA?

Question

I want to prototype an idea for a game I have. The idea for this game is that the player will dig through the ground, creating tunnels and finding treasure.

I'm looking to create 'worms style' terrain, with collision detection for the player wandering and jumping around the tunnels. Examples of this type of dynamic terrain can be seen in these pictures.

My question is how is the best way to implement this type of destructible terrain? I am using XNA game studio.

Answer 1

There's some nice code at the bottom of the this thread. Also, this is a great step-by-step tutorial on achieving a destructible terrain.

EDIT - The original link for the second tutorial was broken, so I've linked to an archived version of it.

Answer 2

Riemer has a similar approach to a game he developed in XNA, cannon shells cause the terrain to be "destroyed" and any props that were previously on said terrain are moved accordingly.

It needs to be refactored and improved for your needs but it's a start.

Riemer has a good selection of tutorials for other things too.

http://www.riemers.net/eng/Tutorials/XNA/Csharp/Series2D/Adding_craters.php

Answer 3

There are two possibilties, eighter one work, but it depends on XNA how easy it is to implement:

• Like others suggested, bitmap masking. You keep a bitmap of all "ground" pixels and all "air" pixels. If you have gravity; a character can't fall through ground, while it can fall through air.
• Vector geometry. You start with a rectangular "ground", and hold a list of "removed" ground, which creates air. This geometry is very simple to edit: just append a circle or similar to the list, and update the graphics. I don't know whether XNA has vector & shape abilities; but it should be easy to create geometry with these two things, and later apply a texture or similar. Also, this can be easy to optimize, by keeping a cached version of the rendered landscape, and only update the cache of the bounding-box of the newly added "air". This solution requires a bit more math though.

Answer 4

Here are two examples that build on each other of how to do this with pixel shaders in XNA 4. Both examples include sourecode.

http://www.syntaxwarriors.com/2012/xna-alpha-mapping-with-pixel-shaders/

http://www.syntaxwarriors.com/2012/xna-alpha-mapping-with-pixel-shader-and-rendertarget2d/

Doing this with pixel shaders is very fast as all the heavy lifting is done on the gpu.