Creating arbitrary concave shapes in XNA/WP7 using sprites/polygons?

What's the best way to draw arbitrary textured shapes in WP7/XNA? I'm thinking I'm going to have to use poly开发者_开发知识库gons in orthographic projection but if there is a method to do this using textures I would much prefer that.

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The best way is with textured polygons in an orthographic projection :)

You could pre-compute textures for sprites in the shapes you want - but that has its own problems. The first two I can think of are: 1) having to implement it! and 2) burning through a whole lot of texture-fetch, fill-rate and texture memory to draw a lot of blank space.