This tutorial covers a basic way of implementing two dimensional fog of war for a game in XNA and assumes you (the reader) has basic knowledge of C# and the XNA Framework. To get things started, create an empty Windows game project. Two textures will be needed: one for the Light and one for the Background. After adding these to the Content Project, go ahead and add the following members to the game class.

1
2
3
4
5
6
7

Texture2D lightTexture;
Texture2D backgroundTexture;
 
RenderTarget2D lightTarget;
RenderTarget2D mainTarget;
 
Effect basicFogOfWarEffect;

While the use of the texture fields is obvious, the use of the render targets may not. The concept behind this fog of war implementation is to draw the light texture to the lightTarget render target and then use the produced texture as the alpha channel for the texture produced from the mainTarget render target.

Read the rest of this entry »