   blending textures
  HiOk, heres what I want to do. (In glOrtho mode)- load two images to the screen. First texture is filled with color. The second texure has an alpha map which makes the center transparent.- I want to apply the second texture to the first so the transparent bit is taken out of the first.what im basically trying to achieve is a landscape in 2d and when you click the mouse a hole appears in the landscape.Or if you can describe a better way of doing it that would be great to.Any help appreciated.Thanks.   
  You could do this with a shader (by using the first texture's RGB but the second channel's alpha channel). I'm not sure if you could achieve this with the fixed functionality blending, however. Another alternative to achieving this same thing might be to use the stencil buffer.   