Function ALG3D_readSTL(): The old version just read the points from the STL. The new version preprocesses these points and returns them as an array of points and an array of indices into the array of points (3 consecutive indices form a triangle).
Handling of triangle meshes:
The new pipeline of working with triangles meshes is the following:
Read the STL file with ALG3D_readSTL (or provide the data by your own).
Create a mesh data structure from these values using ALG3D_createMesh.
Create a tree data structure to perform efficient computations on the mesh using ALG3D_createMeshTree.