Blending operations on integer framebuffer

[soconne]

Why aren't per fragment operations supported on integer textures? Such as blending, alpha test, ect... in OpenGL 3.1? I was trying to implement a simple app that would take the minimum value between the framebuffer and the incoming fragment. Both are 32bit luminance integer formats. But its apparently not supported. Is there any reason for this? Does anybody know of another way to take the minimum of an incoming 32bit integer pixel and what's in the 32bit integer framebuffer?

[ZbuffeR]

I think it has to do with hardware limitations.