blend: combine two images

this one takes the inputs and combines them to the output image. the mode of operation is controlled by the parameters mode and opacity.

current blend modes:

over the output will be (1-opacity) * back + opacity * input
taa use temporal anti-aliasing with box clamping and opacity as parameter
focus stack wavelet transform both back and input and keep only the detail coefficients with larger magnitude
multiply multiplies the back buffer and input

parameters

mode defines the blend mode
mask use or ignore the mask connector
opacity some blend modes use an opacity value
taathrs the threshold for temporal anti aliasing

connectors

input the new top layer
back the back buffer of the composite
mask an optional mask used for certain blend modes. connect a dummy if you don't need it