MultiPassSample

Ok, a few words about the MultiPass shaders in Shoestring. Here is a sample file that these screen shots were taken from.

The concept is very much like the use of the Multi Channel Mixer as shown here. What we’re doing is using a reference shader to control a bunch of other shaders in a scene (ok, I’m lazy, there is only one object in this MultiPass file, but you get the idea, right?) ALL the shaders that you want to control for Multipass purposes should be built this way!

By using MultiPass Control, you get rid of the slider and replace it with a simple radio button to select which shader to use. By using MultiPass Manager, you can select not from two shaders, but from ten. The text fields give you a handy way to add a comment as to what that pass does.

In order to do the shadow pass correctly, you need to turn off Shadows in the render room for all the other passes. This is still a manual process.

So to use the multiple passes, once you have the shaders set up, you simply change the Control shader radio button to the pass you want to perform.

For the purposes of this sample, I just took the stock Lava shader and split it up. You can do stuff like this, or you can do any other task that calls for multiple shaders. I haven’t rendered each of these passes to make sure it does exactly what is desired, but I’m sure you can figure it out.

Note that the Pass Control shader is set to MultiPass Control type. Look just down below for the reason for this.




			Still reading? We use the MultiPass Control in the Pass Control slot because it make the shader easier to work with. When you are setting up the shader, you want to be able to quickly switch between passes as you tune and tweak each one. By changing the radio buttons you can do this easily, and then set it back to Reference when you are done.This is why the reference shader slot exists in MultiPass Control- it isn’t used in the referenced shader.