That kit looks like fun for experimenting!
What I don’t understand is how would you use a vertex shader for drawing and mapping the triangles in space?
Somehow you need to calculate the homography matrix, which is the perspective transformation between two planes.
And this is what is done in the Cinder-Warping tool from @paul.houx, which adds also a bilinear warping
Alternatively you can calculate the intrinsic and extrinsic matrices (see the opencv method) , but if I remember correctly you will need also the Z-coord (so a full 3d model).
If you don’t need to perform any perspective mapping (i.e. solid color per triangle without any 3d information), then you don’t need to calculate anything, and you could just write a simple sketch and draw your shapes with the mouse on the projection window output.
I would suggest to use the cinder-warping block, and find the way to cut out your triangles to warp them independently. I think you don’t need to modify the block, unless it doesn’t support alpha channel.
If you have a good Camera you could check the structured light approach, but it’s a bit tricky the setup and you will need to adjust the output by hand with some warping tool.
I am curious to know if there are more techniques for 2d/3d mapping.
I hope this will be somehow helpful.