Suppose I have a geometry that I am using to create points or an InstancedMesh by utilizing the vertices. However, if I want to change this underlying geometry to something else - such as from a cone to a sphere - that has the same number of vertices, how can I animate between them without relying on MorphTargets? It seems like I might need to utilize a custom vertex shader for this purpose, but I'm unsure about how to pass in the additional BufferGeometries into the vertex shader. I'm struggling to think of a way to achieve this with uniforms since they typically handle int/float/bool/vec/ivec/mat types, but I require multiple vertex buffers. Would it involve using some sort of array?
I'm attempting to come up with a method to work with multiple "complete" geometries within the vertex shader, however, I cannot seem to determine how to access/pass these extra buffers from three.js into WebGL.