But these only cover the “destination end” of the intended copy operation, filling/replacing a rectangular area of the destination texture. A data buffer holding the source pixels still has to be filled using brute force, so to speak. I’m asking for the extraction from an existing source texture, too.
And in fact, the current browser support is too thin to further consider that idea at this point in time.
Any other ideas?
I have, btw., preliminarily solved my problem by using a dedicated PlaneMesh() for each sprite component, translating each to its final position and grouping them into a THREE.Group(). It works, but is obviously a little brute force, and will probably not scale well.
The extraction part from the source texture is currently accomplished through application of suitable uv-coordinates, relative to the source texture, and texturing the destination mesh with the source(!) material/texture.