9.5.2

870 • CHAPTER 18
THE SHADERS • 871
Fusion
Fusion allows you to combine two textures with a mask using the blending modes standard in photo
editing applications, as if they were layers. Using a blend, you can set the opacity of the Blend channel
to mix with the Base channel and also modify the mixing with the Mask channel.
Although Fusion shaders can be ‘stacked’ to allow you to mix more than two textures (by loading
Fusion shaders into the Base and Blend channels), we recommend that you use the Layer shader
instead in such cases. The Layer shader provides a clearer overview than Fusion when more than two
textures are involved in the blend.
Mode
The blend mode used to combine the Blend channel with the Base channel.
Normal
Normal blending, the Blend channel is just mixed with the Base channel.
Multiply
The value of the Blend channel and Base channel are multiplied together.
Screen
Lightens the Base channel by multiplying the inverse of the Blend and Base colors and then inverting
the result. The result is a color that is the same as, or a lightened version, of the Base color.