Reveal mask using a shader?

My end game is to have a reveal effect for our Logo on start up. Instead of using a video created in AE, I thought that I might be able to achieve the same effect by using a shader.

The image is our logo with an alpha gradient applied to it

The shader will reveal the logo over time using the alpha channel as the guide. At time = 0, the logo is hidden, at time=1, the shader lets the background image through where the alpha = 0.01 on the gradient, at time=2, the shader lets the background image through where alpha = 0.02, and so on until time = 100 and the entire image is visible

So as time progresses, the image is revealed based upon how we build the alpha mask. Radially, wipes, whatever.

Is this doable?

Thanks

 

It is doable. In fact, the shaders are already there: Tranparent->Cutout->...
All you have to do is to modifiy the Alpha Cutoff parameter with your script.

 

theres also this,
Dissolve With Texture
http://unifycommunity.com/wiki/index.php?title=Dissolve_With_Texture