Next thing to sort out is the curve of each primary vein.
Referring back to the image, the leading edge of the back wing has a bit of an s-curve to it. The others have gentle curves and some of them are very nearly straight.
For most of the other drawing parameters I’ve been using absolute calculations. For example, the position of the root of each primary vein doesn’t depend on the positions of the other veins. I generate the value from the index of that vein.
I think this makes it easier to reason about what’s going on when I’m tweaking the parameters. Not sure how to express this exactly but it feels like having one less derivative in a chain of derivatives.
However, for the curve of the strand I’m tempted to go with a relative calculation. I already have a quadratic equation describing the direction of each vein at the root. If I set the direction of each segment in that vein using an absolute calculation then I’m going to be shuffling two variables: the index of the vein and the index of the segment in that vein (generation in the code).
Oh but I do need to have both variables in play. The curvature absolutely depends on the vein index as well as the segment index. In this case it’s almost like the first vein should be treated completely differently from the rest so I might use an if statement instead of an equation but that’ll probably cut me off of other potentially desirable wing shapes.
For now let’s see if I can get a curvature that’s close enough.