alLayerFloat

Layer multiple floats together with alpha blending.

Background
The background layer will be blended over 0 if its alpha is not 1
Layer 2
This layer will be blended over lower-numbered layers
Layer 3
This layer will be blended over lower-numbered layers
Layer 4
This layer will be blended over lower-numbered layers
Layer 5
This layer will be blended over lower-numbered layers
Layer 6
This layer will be blended over lower-numbered layers
Layer 7
This layer will be blended over lower-numbered layers
Layer 8
This layer will be blended over lower-numbered layers