export_ply.py

# ##### BEGIN GPL LICENSE BLOCK #####
#
#  This program is free software; you can redistribute it and/or
#  modify it under the terms of the GNU General Public License
#  as published by the Free Software Foundation; either version 2
#  of the License, or (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software Foundation,
#  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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# ##### END GPL LICENSE BLOCK #####

# <pep8-80 compliant>

"""
This script exports Stanford PLY files from Blender. It supports normals,
colors, and texture coordinates per face or per vertex.
Only one mesh can be exported at a time.
"""

import bpy
import os


def save_mesh(
        filepath,
        mesh,
        use_normals=True,
        use_uv_coords=True,
        use_colors=True,
):

    def rvec3d(v):
        return round(v[0], 6), round(v[1], 6), round(v[2], 6)

    def rvec2d(v):
        return round(v[0], 6), round(v[1], 6)

    file = open(filepath, "w", encoding="utf8", newline="\n")
    fw = file.write

    has_uv = bool(mesh.uv_layers)
    has_vcol = bool(mesh.vertex_colors)

    if not has_uv:
        use_uv_coords = False
    if not has_vcol:
        use_colors = False

    if not use_uv_coords:
        has_uv = False
    if not use_colors:
        has_vcol = False

    if has_uv:
        active_uv_layer = mesh.uv_layers.active
        if not active_uv_layer:
            use_uv_coords = False
            has_uv = False
        else:
            active_uv_layer = active_uv_layer.data

    if has_vcol:
        active_col_layer = mesh.vertex_colors.active
        if not active_col_layer:
            use_colors = False
            has_vcol = False
        else:
            active_col_layer = active_col_layer.data

    # in case
    color = uvcoord = uvcoord_key = normal = normal_key = None

    mesh_verts = mesh.vertices  # save a lookup
    ply_verts = []  # list of dictionaries
    # vdict = {} # (index, normal, uv) -> new index
    vdict = [{} for i in range(len(mesh_verts))]
    ply_faces = [[] for f in range(len(mesh.polygons))]
    vert_count = 0
    for i, f in enumerate(mesh.polygons):

        smooth = not use_normals or f.use_smooth
        if not smooth:
            normal = f.normal[:]
            normal_key = rvec3d(normal)

        if has_uv:
            uv = [
                active_uv_layer[l].uv[:]
                for l in range(f.loop_start, f.loop_start + f.loop_total)
            ]
        if has_vcol:
            col = [
                active_col_layer[l].color[:]
                for l in range(f.loop_start, f.loop_start + f.loop_total)
            ]

        pf = ply_faces[i]
        for j, vidx in enumerate(f.vertices):
            v = mesh_verts[vidx]

            if smooth:
                normal = v.normal[:]
                normal_key = rvec3d(normal)

            if has_uv:
                uvcoord = uv[j][0], uv[j][1]
                uvcoord_key = rvec2d(uvcoord)

            if has_vcol:
                color = col[j]
                color = (
                    int(color[0] * 255.0),
                    int(color[1] * 255.0),
                    int(color[2] * 255.0),
                    int(color[3] * 255.0),
                )
            key = normal_key, uvcoord_key, color

            vdict_local = vdict[vidx]
            pf_vidx = vdict_local.get(key)  # Will be None initially

            if pf_vidx is None:  # same as vdict_local.has_key(key)
                pf_vidx = vdict_local[key] = vert_count
                ply_verts.append((vidx, normal, uvcoord, color))
                vert_count += 1

            pf.append(pf_vidx)

    fw("ply\n")
    fw("format ascii 1.0\n")
    fw("comment Created by Blender %s - "
       "www.blender.org, source file: %r\n" %
       (bpy.app.version_string, os.path.basename(bpy.data.filepath)))

    fw("element vertex %d\n" % len(ply_verts))

    fw("property float x\n"
       "property float y\n"
       "property float z\n")

    if use_normals:
        fw("property float nx\n"
           "property float ny\n"
           "property float nz\n")
    if use_uv_coords:
        fw("property float s\n"
           "property float t\n")
    if use_colors:
        fw("property uchar red\n"
           "property uchar green\n"
           "property uchar blue\n"
           "property uchar alpha\n")

    fw("element face %d\n" % len(mesh.polygons))
    fw("property list uchar uint vertex_indices\n")
    fw("end_header\n")

    for i, v in enumerate(ply_verts):
        fw("%.6f %.6f %.6f" % mesh_verts[v[0]].co[:])  # co
        if use_normals:
            fw(" %.6f %.6f %.6f" % v[1])  # no
        if use_uv_coords:
            fw(" %.6f %.6f" % v[2])  # uv
        if use_colors:
            fw(" %u %u %u %u" % v[3])  # col
        fw("\n")

    for pf in ply_faces:
        # fw(f"{len(pf)} {' '.join(str(x) for x in pf)}\n")
        fw("%d" % len(pf))
        for v in pf:
            fw(" %d" % v)
        fw("\n")

    file.close()
    print("writing %r done" % filepath)

    return {'FINISHED'}


def save(
        operator,
        context,
        filepath="",
        use_mesh_modifiers=True,
        use_normals=True,
        use_uv_coords=True,
        use_colors=True,
        global_matrix=None
):
    obj = context.active_object

    if global_matrix is None:
        from mathutils import Matrix
        global_matrix = Matrix()

    if bpy.ops.object.mode_set.poll():
        bpy.ops.object.mode_set(mode='OBJECT')

    mesh_owner_object = None
    if use_mesh_modifiers and obj.modifiers:
        depsgraph = context.evaluated_depsgraph_get()
        mesh_owner_object = obj.evaluated_get(depsgraph)
        mesh = mesh_owner_object.to_mesh()
    else:
        mesh_owner_object = obj
        mesh = mesh_owner_object.to_mesh()

    if not mesh:
        raise Exception("Error, could not get mesh data from active object")

    mesh.transform(global_matrix @ obj.matrix_world)
    if use_normals:
        mesh.calc_normals()

    ret = save_mesh(filepath, mesh,
                    use_normals=use_normals,
                    use_uv_coords=use_uv_coords,
                    use_colors=use_colors,
                    )

    mesh_owner_object.to_mesh_clear()

    return ret