test

ctm_export.py

from ctypes import *
from openctm import *
from contextlib import contextmanager

import bpy
import bmesh


def pydata_from_bmesh(bm):
    v = [v.co[:] for v in bm.verts]
    # e = [[i.index for i in e.verts] for e in bm.edges[:]]
    p = [[i.index for i in p.verts] for p in bm.faces[:]]
    return v, p


@contextmanager
def ctm_features():

    def make_blob(geom, T):
        """Convert into a ctypes flat pointer-to-array"""
        size = len(geom) * len(geom[0])
        Blob = T * size
        geom_data_type = [c for v in geom for c in v]
        blob = Blob(*geom_data_type)
        return cast(blob, POINTER(T))

    ctmDefineMesh = _lib.ctmDefineMesh
    ctmDefineMesh.argtypes = [
        CTMcontext,
        POINTER(CTMfloat), CTMuint,  # * to vertex data & vertex count
        POINTER(CTMuint), CTMuint,  # * to index data & triangle count
        POINTER(CTMfloat)]  # Optional * to surface normals
    yield ctmDefineMesh
    yield make_blob


def write_ctm(filename, verts, faces):

    with ctm_features() as (ctmDefineMesh, make_blob):
        pVerts = make_blob(verts, c_float)
        pFaces = make_blob(faces, c_uint)
        pNormals = POINTER(c_float)()
        ctm = ctmNewContext(CTM_EXPORT)
        ctmDefineMesh(ctm, pVerts, len(verts), pFaces, len(faces), pNormals)
        ctmSave(ctm, filename)
        ctmFreeContext(ctm)


def get_triangulated_mesh(obj):
    # Get the active mesh
    me = bpy.context.object.data
    bm = bmesh.new()
    bm.from_mesh(me)
    bmesh.ops.triangulate(bm, faces=bm.faces, quad_method=0, ngon_method=0)

    geometry = pydata_from_bmesh(bm)
    write_ctm(filename, *geometry)
    bm.free()  # free and prevent further access