render.py

                                        file.write(", ")
                                        file.write("<%d,%d,%d>" % (
                                                 uniqueUVs[uvs[0]][0],\
                                                 uniqueUVs[uvs[1]][0],\
                                                 uniqueUVs[uvs[2]][0]))

                                file.write("\n")
                                tabWrite("}\n")

                            #XXX BOOLEAN
                            onceCSG = 0
                            for mod in ob.modifiers:
                                if onceCSG == 0:
                                    if mod :
                                        if mod.type == 'BOOLEAN':
                                            if ob.pov.boolean_mod == "POV":
                                                file.write("\tinside_vector <%.6g, %.6g, %.6g>\n" %
                                                           (ob.pov.inside_vector[0],
                                                            ob.pov.inside_vector[1],
                                                            ob.pov.inside_vector[2]))
                                                onceCSG = 1

                            if me.materials:
                                try:
                                    material = me.materials[0]  # dodgy
                                    writeObjectMaterial(material, ob)
                                except IndexError:
                                    print(me)

                            # POV object modifiers such as
                            # hollow / sturm / double_illuminate etc.
                            write_object_modifiers(scene,ob,file)

                            #Importance for radiosity sampling added here:
                            tabWrite("radiosity { \n")
                            tabWrite("importance %3g \n" % importance)
                            tabWrite("}\n")

                            tabWrite("}\n")  # End of mesh block
                        else:
                            facesMaterials = [] # WARNING!!!!!!!!!!!!!!!!!!!!!!
                            if me_materials:
                                for f in me_faces:
                                    if f.material_index not in facesMaterials:
                                        facesMaterials.append(f.material_index)
                            # No vertex colors, so write material colors as vertex colors
                            for i, material in enumerate(me_materials):

                                if material and material.pov.material_use_nodes == False:  # WARNING!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
                                    # Multiply diffuse with SSS Color
                                    if material.pov_subsurface_scattering.use:
                                        diffuse_color = [i * j for i, j in zip(material.pov_subsurface_scattering.color[:], material.diffuse_color[:])]
                                        key = diffuse_color[0], diffuse_color[1], diffuse_color[2], i  # i == f.mat
                                        vertCols[key] = [-1]
                                    else:
                                        diffuse_color = material.diffuse_color[:]
                                        key = diffuse_color[0], diffuse_color[1], diffuse_color[2], i  # i == f.mat
                                        vertCols[key] = [-1]

                                    idx = 0
                                    LocalMaterialNames = []
                                    for col, index in vertCols.items():
                                        #if me_materials:
                                        mater = me_materials[col[3]]
                                        if me_materials is None: #XXX working?
                                            material_finish = DEF_MAT_NAME  # not working properly,
                                            trans = 0.0

                                        else:
                                            shading.writeTextureInfluence(mater, materialNames,
                                                                            LocalMaterialNames,
                                                                            path_image, lampCount,
                                                                            imageFormat, imgMap,
                                                                            imgMapTransforms,
                                                                            tabWrite, comments,
                                                                            string_strip_hyphen,
                                                                            safety, col, os, preview_dir,  unpacked_images)
                                        ###################################################################
                                        index[0] = idx
                                        idx += 1



                            # Vert Colors
                            tabWrite("texture_list {\n")
                            # In case there's is no material slot, give at least one texture
                            #(an empty one so it uses pov default)
                            if len(vertCols)==0:
                                file.write(tabStr + "1")
                            else:
                                file.write(tabStr + "%s" % (len(vertCols)))  # vert count




                            # below "material" alias, added check ob.active_material
                            # to avoid variable referenced before assignment error
                            try:
                                material = ob.active_material
                            except IndexError:
                                #when no material slot exists,
                                material=None

                            # WARNING!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
                            if material and ob.active_material is not None and material.pov.material_use_nodes == False:
                                if material.pov.replacement_text != "":
                                    file.write("\n")
                                    file.write(" texture{%s}\n" % material.pov.replacement_text)

                                else:
                                    # Loop through declared materials list
                                    for cMN in LocalMaterialNames:
                                        if material != "Default":
                                            file.write("\n texture{MAT_%s}\n" % cMN)
                                            #use string_strip_hyphen(materialNames[material]))
                                            #or Something like that to clean up the above?
                            elif material and material.pov.material_use_nodes:
                                for index in facesMaterials:
                                    faceMaterial = string_strip_hyphen(bpy.path.clean_name(me_materials[index].name))
                                    file.write("\n texture{%s}\n" % faceMaterial)
                            # END!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
                            else:
                                file.write(" texture{}\n")
                            tabWrite("}\n")

                            # Face indices
                            tabWrite("face_indices {\n")
                            tabWrite("%d" % (len(me_faces)))  # faces count
                            tabStr = tab * tabLevel

                            for fi, f in enumerate(me_faces):
                                fv = faces_verts[fi]
                                material_index = f.material_index

                                if vcol_layer:
                                    cols = [vcol_layer[l].color[:] for l in f.loops]

                                if not me_materials or me_materials[material_index] is None:  # No materials
                                    if linebreaksinlists:
                                        file.write(",\n")
                                        # vert count
                                        file.write(tabStr + "<%d,%d,%d>" % (fv[0], fv[1], fv[2]))
                                    else:
                                        file.write(", ")
                                        file.write("<%d,%d,%d>" % (fv[0], fv[1], fv[2]))  # vert count
                                else:
                                    material = me_materials[material_index]
                                    ci1 = ci2 = ci3 = f.material_index
                                    if me.vertex_colors: #and material.use_vertex_color_paint:
                                        # Color per vertex - vertex color

                                        col1 = cols[0]
                                        col2 = cols[1]
                                        col3 = cols[2]

                                        ci1 = vertCols[col1[0], col1[1], col1[2], material_index][0]
                                        ci2 = vertCols[col2[0], col2[1], col2[2], material_index][0]
                                        ci3 = vertCols[col3[0], col3[1], col3[2], material_index][0]
                                    elif material.pov.material_use_nodes:
                                        ci1 = ci2 = ci3 = 0
                                    else:
                                        # Color per material - flat material color
                                        if material.pov_subsurface_scattering.use:
                                            diffuse_color = [i * j for i, j in
                                                zip(material.pov_subsurface_scattering.color[:],
                                                    material.diffuse_color[:])]
                                        else:
                                            diffuse_color = material.diffuse_color[:]
                                        ci1 = ci2 = ci3 = vertCols[diffuse_color[0], diffuse_color[1], \
                                                          diffuse_color[2], f.material_index][0]

                                    if linebreaksinlists:
                                        file.write(",\n")
                                        file.write(tabStr + "<%d,%d,%d>, %d,%d,%d" % \
                                                   (fv[0], fv[1], fv[2], ci1, ci2, ci3))  # vert count
                                    else:
                                        file.write(", ")
                                        file.write("<%d,%d,%d>, %d,%d,%d" % \
                                                   (fv[0], fv[1], fv[2], ci1, ci2, ci3))  # vert count

                            file.write("\n")
                            tabWrite("}\n")

                            # normal_indices indices
                            tabWrite("normal_indices {\n")
                            tabWrite("%d" % (len(me_faces)))  # faces count
                            tabStr = tab * tabLevel
                            for fi, fv in enumerate(faces_verts):
                                if me_faces[fi].use_smooth:
                                    if linebreaksinlists:
                                        file.write(",\n")
                                        file.write(tabStr + "<%d,%d,%d>" %\
                                        (uniqueNormals[verts_normals[fv[0]]][0],\
                                         uniqueNormals[verts_normals[fv[1]]][0],\
                                         uniqueNormals[verts_normals[fv[2]]][0]))  # vert count
                                    else:
                                        file.write(", ")
                                        file.write("<%d,%d,%d>" %\
                                        (uniqueNormals[verts_normals[fv[0]]][0],\
                                         uniqueNormals[verts_normals[fv[1]]][0],\
                                         uniqueNormals[verts_normals[fv[2]]][0]))  # vert count
                                else:
                                    idx = uniqueNormals[faces_normals[fi]][0]
                                    if linebreaksinlists:
                                        file.write(",\n")
                                        file.write(tabStr + "<%d,%d,%d>" % (idx, idx, idx)) # vertcount
                                    else:
                                        file.write(", ")
                                        file.write("<%d,%d,%d>" % (idx, idx, idx))  # vert count

                            file.write("\n")
                            tabWrite("}\n")

                            if uv_layer:
                                tabWrite("uv_indices {\n")
                                tabWrite("%d" % (len(me_faces)))  # faces count
                                tabStr = tab * tabLevel
                                for f in me_faces:
                                    uvs = [uv_layer[l].uv[:] for l in f.loops]

                                    if linebreaksinlists:
                                        file.write(",\n")
                                        file.write(tabStr + "<%d,%d,%d>" % (
                                                 uniqueUVs[uvs[0]][0],\
                                                 uniqueUVs[uvs[1]][0],\
                                                 uniqueUVs[uvs[2]][0]))
                                    else:
                                        file.write(", ")
                                        file.write("<%d,%d,%d>" % (
                                                 uniqueUVs[uvs[0]][0],\
                                                 uniqueUVs[uvs[1]][0],\
                                                 uniqueUVs[uvs[2]][0]))

                                file.write("\n")
                                tabWrite("}\n")

                            #XXX BOOLEAN
                            onceCSG = 0
                            for mod in ob.modifiers:
                                if onceCSG == 0:
                                    if mod :
                                        if mod.type == 'BOOLEAN':
                                            if ob.pov.boolean_mod == "POV":
                                                file.write("\tinside_vector <%.6g, %.6g, %.6g>\n" %
                                                           (ob.pov.inside_vector[0],
                                                            ob.pov.inside_vector[1],
                                                            ob.pov.inside_vector[2]))
                                                onceCSG = 1

                            if me.materials:
                                try:
                                    material = me.materials[0]  # dodgy
                                    writeObjectMaterial(material, ob)
                                except IndexError:
                                    print(me)

                            # POV object modifiers such as
                            # hollow / sturm / double_illuminate etc.
                            write_object_modifiers(scene,ob,file)

                            #Importance for radiosity sampling added here:
                            tabWrite("radiosity { \n")
                            tabWrite("importance %3g \n" % importance)
                            tabWrite("}\n")

                            tabWrite("}\n")  # End of mesh block



                        ob_eval.to_mesh_clear()

        if csg:
            duplidata_ref = []
            _dupnames_seen = dict()  # avoid duplicate output during introspection
            for ob in sel:
                #matrix = global_matrix @ ob.matrix_world
                if ob.is_instancer:
                    tabWrite("\n//--DupliObjects in %s--\n\n"% ob.name)
                    #ob.dupli_list_create(scene) #deprecated in 2.8
                    depsgraph = bpy.context.evaluated_depsgraph_get()
                    dup = ""
                    if ob.is_modified(scene, 'RENDER'):
                        #modified object always unique so using object name rather than data name
                        dup = "#declare OB%s = union{\n" %(string_strip_hyphen(bpy.path.clean_name(ob.name)))
                    else:
                        dup = "#declare DATA%s = union{\n" %(string_strip_hyphen(bpy.path.clean_name(ob.name)))
                    for eachduplicate in depsgraph.object_instances:
                        if eachduplicate.is_instance:  # Real dupli instance filtered because original included in list since 2.8
                            _dupname = eachduplicate.object.name
                            _dupobj = bpy.data.objects[_dupname]
                            # BEGIN introspection for troubleshooting purposes
                            if not "name" in dir(_dupobj.data):
                                if _dupname not in _dupnames_seen:
                                    print("WARNING: bpy.data.objects[%s].data (of type %s) has no 'name' attribute" % (_dupname, type(_dupobj.data)))
                                    for _thing in dir(_dupobj):
                                        print("||  %s.%s = %s" % (_dupname, _thing, getattr(_dupobj, _thing)))
                                    _dupnames_seen[_dupname] = 1
                                    print("''=>  Unparseable objects so far: %s" % (_dupnames_seen))
                                else:
                                    _dupnames_seen[_dupname] += 1
                                continue  # don't try to parse data objects with no name attribute
                            # END introspection for troubleshooting purposes
                            duplidataname = "OB"+string_strip_hyphen(bpy.path.clean_name(_dupobj.data.name))
                            dupmatrix = eachduplicate.matrix_world.copy() #has to be copied to not store instance since 2.8
                            dup += ("\tobject {\n\t\tDATA%s\n\t\t%s\t}\n" %(string_strip_hyphen(bpy.path.clean_name(_dupobj.data.name)), MatrixAsPovString(ob.matrix_world.inverted() @ dupmatrix)))
                            #add object to a list so that it is not rendered for some instance_types
                            if ob.instance_type not in {'COLLECTION'} and duplidataname not in duplidata_ref:
                                duplidata_ref.append(duplidataname) #older key [string_strip_hyphen(bpy.path.clean_name("OB"+ob.name))]
                    dup += "}\n"
                    #ob.dupli_list_clear()# just do not store any reference to instance since 2.8
                    tabWrite(dup)
                else:
                    continue
            print("WARNING: Unparseable objects in current .blend file:\n''=> %s" % (_dupnames_seen))
            print("duplidata_ref = %s" % (duplidata_ref))
            for data_name, inst in data_ref.items():
                for ob_name, matrix_str in inst:
                    if ob_name not in duplidata_ref: #.items() for a dictionary
                        tabWrite("\n//----Blender Object Name:%s----\n" % ob_name)
                        if ob.pov.object_as == '':
                            tabWrite("object { \n")
                            tabWrite("%s\n" % data_name)
                            tabWrite("%s\n" % matrix_str)
                            tabWrite("}\n")
                        else:
                            no_boolean = True
                            for mod in ob.modifiers:
                                if mod.type == 'BOOLEAN':
                                    operation = None
                                    no_boolean = False
                                    if mod.operation == 'INTERSECT':
                                        operation = 'intersection'
                                    else:
                                        operation = mod.operation.lower()
                                    mod_ob_name = string_strip_hyphen(bpy.path.clean_name(mod.object.name))
                                    mod_matrix = global_matrix @ mod.object.matrix_world
                                    mod_ob_matrix = MatrixAsPovString(mod_matrix)
                                    tabWrite("%s { \n"%operation)
                                    tabWrite("object { \n")
                                    tabWrite("%s\n" % data_name)
                                    tabWrite("%s\n" % matrix_str)
                                    tabWrite("}\n")
                                    tabWrite("object { \n")
                                    tabWrite("%s\n" % ('DATA'+ mod_ob_name))
                                    tabWrite("%s\n" % mod_ob_matrix)
                                    tabWrite("}\n")
                                    tabWrite("}\n")
                                    break
                            if no_boolean:
                                tabWrite("object { \n")
                                tabWrite("%s\n" % data_name)
                                tabWrite("%s\n" % matrix_str)
                                tabWrite("}\n")

    def exportWorld(world):
        """write world as POV backgrounbd and sky_sphere to exported file """
        render = scene.pov
        camera = scene.camera
        matrix = global_matrix @ camera.matrix_world
        if not world:
            return
        #############Maurice####################################
        #These lines added to get sky gradient (visible with PNG output)
        if world:
            #For simple flat background:
            if not world.pov.use_sky_blend:
                # Non fully transparent background could premultiply alpha and avoid anti-aliasing
                # display issue:
                if render.alpha_mode == 'TRANSPARENT':
                    tabWrite("background {rgbt<%.3g, %.3g, %.3g, 0.75>}\n" % \
                             (world.pov.horizon_color[:]))
                #Currently using no alpha with Sky option:
                elif render.alpha_mode == 'SKY':
                    tabWrite("background {rgbt<%.3g, %.3g, %.3g, 0>}\n" % (world.pov.horizon_color[:]))
                #StraightAlpha:
                # XXX Does not exists anymore
                #else:
                    #tabWrite("background {rgbt<%.3g, %.3g, %.3g, 1>}\n" % (world.pov.horizon_color[:]))

            worldTexCount = 0
            #For Background image textures
            for t in world.texture_slots:  # risk to write several sky_spheres but maybe ok.
                if t and t.texture.type is not None:
                    worldTexCount += 1
                # XXX No enable checkbox for world textures yet (report it?)
                #if t and t.texture.type == 'IMAGE' and t.use:
                if t and t.texture.type == 'IMAGE':
                    image_filename = path_image(t.texture.image)
                    if t.texture.image.filepath != image_filename:
                        t.texture.image.filepath = image_filename
                    if image_filename != "" and t.use_map_blend:
                        texturesBlend = image_filename
                        #colvalue = t.default_value
                        t_blend = t

                    # Commented below was an idea to make the Background image oriented as camera
                    # taken here:
#http://news.pov.org/pov.newusers/thread/%3Cweb.4a5cddf4e9c9822ba2f93e20@news.pov.org%3E/
                    # Replace 4/3 by the ratio of each image found by some custom or existing
                    # function
                    #mappingBlend = (" translate <%.4g,%.4g,%.4g> rotate z*degrees" \
                    #                "(atan((camLocation - camLookAt).x/(camLocation - " \
                    #                "camLookAt).y)) rotate x*degrees(atan((camLocation - " \
                    #                "camLookAt).y/(camLocation - camLookAt).z)) rotate y*" \
                    #                "degrees(atan((camLocation - camLookAt).z/(camLocation - " \
                    #                "camLookAt).x)) scale <%.4g,%.4g,%.4g>b" % \
                    #                (t_blend.offset.x / 10 , t_blend.offset.y / 10 ,
                    #                 t_blend.offset.z / 10, t_blend.scale.x ,
                    #                 t_blend.scale.y , t_blend.scale.z))
                    #using camera rotation valuesdirectly from blender seems much easier
                    if t_blend.texture_coords == 'ANGMAP':
                        mappingBlend = ""
                    else:
                        # POV-Ray "scale" is not a number of repetitions factor, but its
                        # inverse, a standard scale factor.
                        # 0.5 Offset is needed relatively to scale because center of the
                        # UV scale is 0.5,0.5 in blender and 0,0 in POV
                        # Further Scale by 2 and translate by -1 are
                        # required for the sky_sphere not to repeat

                        mappingBlend = "scale 2 scale <%.4g,%.4g,%.4g> translate -1 " \
                                       "translate <%.4g,%.4g,%.4g> rotate<0,0,0> " % \
                                       ((1.0 / t_blend.scale.x),
                                       (1.0 / t_blend.scale.y),
                                       (1.0 / t_blend.scale.z),
                                       0.5-(0.5/t_blend.scale.x)- t_blend.offset.x,
                                       0.5-(0.5/t_blend.scale.y)- t_blend.offset.y,
                                       t_blend.offset.z)

                        # The initial position and rotation of the pov camera is probably creating
                        # the rotation offset should look into it someday but at least background
                        # won't rotate with the camera now.
                    # Putting the map on a plane would not introduce the skysphere distortion and
                    # allow for better image scale matching but also some waay to chose depth and
                    # size of the plane relative to camera.
                    tabWrite("sky_sphere {\n")
                    tabWrite("pigment {\n")
                    tabWrite("image_map{%s \"%s\" %s}\n" % \
                             (imageFormat(texturesBlend), texturesBlend, imgMapBG(t_blend)))
                    tabWrite("}\n")
                    tabWrite("%s\n" % (mappingBlend))
                    # The following layered pigment opacifies to black over the texture for
                    # transmit below 1 or otherwise adds to itself
                    tabWrite("pigment {rgb 0 transmit %s}\n" % (t.texture.intensity))
                    tabWrite("}\n")
                    #tabWrite("scale 2\n")
                    #tabWrite("translate -1\n")

            #For only Background gradient

            if worldTexCount == 0:
                if world.pov.use_sky_blend:
                    tabWrite("sky_sphere {\n")
                    tabWrite("pigment {\n")
                    # maybe Should follow the advice of POV doc about replacing gradient
                    # for skysphere..5.5
                    tabWrite("gradient y\n")
                    tabWrite("color_map {\n")
                    # XXX Does not exists anymore
                    #if render.alpha_mode == 'STRAIGHT':
                        #tabWrite("[0.0 rgbt<%.3g, %.3g, %.3g, 1>]\n" % (world.pov.horizon_color[:]))
                        #tabWrite("[1.0 rgbt<%.3g, %.3g, %.3g, 1>]\n" % (world.pov.zenith_color[:]))
                    if render.alpha_mode == 'TRANSPARENT':
                        tabWrite("[0.0 rgbt<%.3g, %.3g, %.3g, 0.99>]\n" % (world.pov.horizon_color[:]))
                        # aa premult not solved with transmit 1
                        tabWrite("[1.0 rgbt<%.3g, %.3g, %.3g, 0.99>]\n" % (world.pov.zenith_color[:]))
                    else:
                        tabWrite("[0.0 rgbt<%.3g, %.3g, %.3g, 0>]\n" % (world.pov.horizon_color[:]))
                        tabWrite("[1.0 rgbt<%.3g, %.3g, %.3g, 0>]\n" % (world.pov.zenith_color[:]))
                    tabWrite("}\n")
                    tabWrite("}\n")
                    tabWrite("}\n")
                    # Sky_sphere alpha (transmit) is not translating into image alpha the same
                    # way as 'background'

            #if world.pov.light_settings.use_indirect_light:
            #    scene.pov.radio_enable=1

            # Maybe change the above to a function copyInternalRenderer settings when
            # user pushes a button, then:
            #scene.pov.radio_enable = world.pov.light_settings.use_indirect_light
            # and other such translations but maybe this would not be allowed either?

        ###############################################################

        mist = world.mist_settings

        if mist.use_mist:
            tabWrite("fog {\n")
            if mist.falloff=='LINEAR':
                tabWrite("distance %.6f\n" % ((mist.start+mist.depth)*0.368))
            elif mist.falloff=='QUADRATIC':    # n**2 or squrt(n)?
                tabWrite("distance %.6f\n" % ((mist.start+mist.depth)**2*0.368))
            elif mist.falloff=='INVERSE_QUADRATIC':    # n**2 or squrt(n)?
                tabWrite("distance %.6f\n" % ((mist.start+mist.depth)**2*0.368))
            tabWrite("color rgbt<%.3g, %.3g, %.3g, %.3g>\n" % \
                     (*world.pov.horizon_color, 1.0 - mist.intensity))
            #tabWrite("fog_offset %.6f\n" % mist.start) #create a pov property to prepend
            #tabWrite("fog_alt %.6f\n" % mist.height) #XXX right?
            #tabWrite("turbulence 0.2\n")
            #tabWrite("turb_depth 0.3\n")
            tabWrite("fog_type 1\n") #type2 for height
            tabWrite("}\n")
        if scene.pov.media_enable:
            tabWrite("media {\n")
            tabWrite("scattering { %d, rgb %.12f*<%.4g, %.4g, %.4g>\n" % \
                     (int(scene.pov.media_scattering_type),
                     (scene.pov.media_diffusion_scale),
                     *(scene.pov.media_diffusion_color[:])))
            if scene.pov.media_scattering_type == '5':
                tabWrite("eccentricity %.3g\n" % scene.pov.media_eccentricity)
            tabWrite("}\n")
            tabWrite("absorption %.12f*<%.4g, %.4g, %.4g>\n" % \
                     (scene.pov.media_absorption_scale,
                     *(scene.pov.media_absorption_color[:])))
            tabWrite("\n")
            tabWrite("samples %.d\n" % scene.pov.media_samples)
            tabWrite("}\n")

    def exportGlobalSettings(scene):
        """write all POV global settings to exported file """
        tabWrite("global_settings {\n")
        tabWrite("assumed_gamma 1.0\n")
        tabWrite("max_trace_level %d\n" % scene.pov.max_trace_level)

        if scene.pov.charset != 'ascii':
            file.write("    charset %s\n"%scene.pov.charset)
        if scene.pov.global_settings_advanced:
            if scene.pov.radio_enable == False:
                file.write("    adc_bailout %.6f\n"%scene.pov.adc_bailout)
            file.write("    ambient_light <%.6f,%.6f,%.6f>\n"%scene.pov.ambient_light[:])
            file.write("    irid_wavelength <%.6f,%.6f,%.6f>\n"%scene.pov.irid_wavelength[:])
            file.write("    max_intersections %s\n"%scene.pov.max_intersections)
            file.write("    number_of_waves %s\n"%scene.pov.number_of_waves)
            file.write("    noise_generator %s\n"%scene.pov.noise_generator)
        if scene.pov.radio_enable:
            tabWrite("radiosity {\n")
            tabWrite("adc_bailout %.4g\n" % scene.pov.radio_adc_bailout)
            tabWrite("brightness %.4g\n" % scene.pov.radio_brightness)
            tabWrite("count %d\n" % scene.pov.radio_count)
            tabWrite("error_bound %.4g\n" % scene.pov.radio_error_bound)
            tabWrite("gray_threshold %.4g\n" % scene.pov.radio_gray_threshold)
            tabWrite("low_error_factor %.4g\n" % scene.pov.radio_low_error_factor)
            tabWrite("maximum_reuse %.4g\n" % scene.pov.radio_maximum_reuse)
            tabWrite("minimum_reuse %.4g\n" % scene.pov.radio_minimum_reuse)
            tabWrite("nearest_count %d\n" % scene.pov.radio_nearest_count)
            tabWrite("pretrace_start %.3g\n" % scene.pov.radio_pretrace_start)
            tabWrite("pretrace_end %.3g\n" % scene.pov.radio_pretrace_end)
            tabWrite("recursion_limit %d\n" % scene.pov.radio_recursion_limit)
            tabWrite("always_sample %d\n" % scene.pov.radio_always_sample)
            tabWrite("normal %d\n" % scene.pov.radio_normal)
            tabWrite("media %d\n" % scene.pov.radio_media)
            tabWrite("subsurface %d\n" % scene.pov.radio_subsurface)
            tabWrite("}\n")
        onceSss = 1
        onceAmbient = 1
        oncePhotons = 1
        for material in bpy.data.materials:
            if material.pov_subsurface_scattering.use and onceSss:
                # In pov, the scale has reversed influence compared to blender. these number
                # should correct that
                tabWrite("mm_per_unit %.6f\n" % \
                         (material.pov_subsurface_scattering.scale * 1000.0))
                         # 1000 rather than scale * (-100.0) + 15.0))

                # In POV-Ray, the scale factor for all subsurface shaders needs to be the same

                # formerly sslt_samples were multiplied by 100 instead of 10
                sslt_samples = (11 - material.pov_subsurface_scattering.error_threshold) * 10

                tabWrite("subsurface { samples %d, %d }\n" % (sslt_samples, sslt_samples / 10))
                onceSss = 0

            if world and onceAmbient:
                tabWrite("ambient_light rgb<%.3g, %.3g, %.3g>\n" % world.pov.ambient_color[:])
                onceAmbient = 0

            if scene.pov.photon_enable:
                if (oncePhotons and
                        (material.pov.refraction_type == "2" or
                        material.pov.photons_reflection == True)):
                    tabWrite("photons {\n")
                    tabWrite("spacing %.6f\n" % scene.pov.photon_spacing)
                    tabWrite("max_trace_level %d\n" % scene.pov.photon_max_trace_level)
                    tabWrite("adc_bailout %.3g\n" % scene.pov.photon_adc_bailout)
                    tabWrite("gather %d, %d\n" % (scene.pov.photon_gather_min,
                        scene.pov.photon_gather_max))
                    if scene.pov.photon_map_file_save_load in {'save'}:
                        filePhName = 'Photon_map_file.ph'
                        if scene.pov.photon_map_file != '':
                            filePhName = scene.pov.photon_map_file+'.ph'
                        filePhDir = tempfile.gettempdir()
                        path = bpy.path.abspath(scene.pov.photon_map_dir)
                        if os.path.exists(path):
                            filePhDir = path
                        fullFileName = os.path.join(filePhDir,filePhName)
                        tabWrite('save_file "%s"\n'%fullFileName)
                        scene.pov.photon_map_file = fullFileName
                    if scene.pov.photon_map_file_save_load in {'load'}:
                        fullFileName = bpy.path.abspath(scene.pov.photon_map_file)
                        if os.path.exists(fullFileName):
                            tabWrite('load_file "%s"\n'%fullFileName)
                    tabWrite("}\n")
                    oncePhotons = 0

        tabWrite("}\n")

    def exportCustomCode():
        """write all POV user defined custom code to exported file """
        # Write CurrentAnimation Frame for use in Custom POV Code
        file.write("#declare CURFRAMENUM = %d;\n" % bpy.context.scene.frame_current)
        #Change path and uncomment to add an animated include file by hand:
        file.write("//#include \"/home/user/directory/animation_include_file.inc\"\n")
        for txt in bpy.data.texts:
            if txt.pov.custom_code == 'both':
                # Why are the newlines needed?
                file.write("\n")
                file.write(txt.as_string())
                file.write("\n")

    #sel = renderable_objects(scene) #removed for booleans
    if comments:
        file.write("//----------------------------------------------\n" \
                   "//--Exported with POV-Ray exporter for Blender--\n" \
                   "//----------------------------------------------\n\n")
    file.write("#version 3.7;\n")
    file.write("#declare Default_texture = texture{pigment {rgb 0.8} "
               "finish {brilliance 3.8} }\n\n")
    if comments:
        file.write("\n//--Global settings--\n\n")

    exportGlobalSettings(scene)


    if comments:
        file.write("\n//--Custom Code--\n\n")
    exportCustomCode()

    if comments:
        file.write("\n//--Patterns Definitions--\n\n")
    LocalPatternNames = []
    for texture in bpy.data.textures: #ok?
        if texture.users > 0:
            currentPatName = string_strip_hyphen(bpy.path.clean_name(texture.name))
            #string_strip_hyphen(patternNames[texture.name]) #maybe instead of the above
            LocalPatternNames.append(currentPatName)
            #use above list to prevent writing texture instances several times and assign in mats?
            if (texture.type not in {'NONE', 'IMAGE'} and texture.pov.tex_pattern_type == 'emulator')or(texture.type in {'NONE', 'IMAGE'} and texture.pov.tex_pattern_type != 'emulator'):
                file.write("\n#declare PAT_%s = \n" % currentPatName)
                file.write(shading.exportPattern(texture, string_strip_hyphen))
            file.write("\n")
    if comments:
        file.write("\n//--Background--\n\n")

    exportWorld(scene.world)

    if comments:
        file.write("\n//--Cameras--\n\n")

    exportCamera()

    if comments:
        file.write("\n//--Lamps--\n\n")

    for ob in bpy.data.objects:
        if ob.type == 'MESH':
            for mod in ob.modifiers:
                if mod.type == 'BOOLEAN':
                    if mod.object not in csg_list:
                        csg_list.append(mod.object)
    if csg_list != []:
        csg = False
        sel = no_renderable_objects(scene)
        exportMeshes(scene, sel, csg)

    csg = True
    sel = renderable_objects(scene)

    exportLamps([L for L in sel if (L.type == 'LIGHT' and L.pov.object_as != 'RAINBOW')])

    if comments:
        file.write("\n//--Rainbows--\n\n")
    exportRainbows([L for L in sel if (L.type == 'LIGHT' and L.pov.object_as == 'RAINBOW')])


    if comments:
        file.write("\n//--Special Curves--\n\n")
    for c in sel:
        if c.is_modified(scene, 'RENDER'):
            continue #don't export as pov curves objects with modifiers, but as mesh
        elif c.type == 'CURVE' and (c.pov.curveshape in {'lathe','sphere_sweep','loft','birail'}):
            exportCurves(scene,c)


    if comments:
        file.write("\n//--Material Definitions--\n\n")
    # write a default pigment for objects with no material (comment out to show black)
    file.write("#default{ pigment{ color srgb 0.8 }}\n")
    # Convert all materials to strings we can access directly per vertex.
    #exportMaterials()
    shading.writeMaterial(using_uberpov, DEF_MAT_NAME, scene, tabWrite, safety, comments, uniqueName, materialNames, None)  # default material
    for material in bpy.data.materials:
        if material.users > 0:
            if material.pov.material_use_nodes:
                ntree = material.node_tree
                povMatName=string_strip_hyphen(bpy.path.clean_name(material.name))
                if len(ntree.nodes)==0:
                    file.write('#declare %s = texture {%s}\n'%(povMatName,color))
                else:
                    shading.write_nodes(scene,povMatName,ntree,file)

                for node in ntree.nodes:
                    if node:
                        if node.bl_idname == "PovrayOutputNode":
                            if node.inputs["Texture"].is_linked:
                                for link in ntree.links:
                                    if link.to_node.bl_idname == "PovrayOutputNode":
                                        povMatName=string_strip_hyphen(bpy.path.clean_name(link.from_node.name))+"_%s"%povMatName
                            else:
                                file.write('#declare %s = texture {%s}\n'%(povMatName,color))
            else:
                shading.writeMaterial(using_uberpov, DEF_MAT_NAME, scene, tabWrite, safety, comments, uniqueName, materialNames, material)
            # attributes are all the variables needed by the other python file...
    if comments:
        file.write("\n")

    exportMeta([m for m in sel if m.type == 'META'])

    if comments:
        file.write("//--Mesh objects--\n")

    exportMeshes(scene, sel, csg)

    #What follow used to happen here:
    #exportCamera()
    #exportWorld(scene.world)
    #exportGlobalSettings(scene)
    # MR:..and the order was important for implementing pov 3.7 baking
    #      (mesh camera) comment for the record
    # CR: Baking should be a special case than. If "baking", than we could change the order.

    #print("pov file closed %s" % file.closed)
    file.close()
    #print("pov file closed %s" % file.closed)


def write_pov_ini(scene, filename_ini, filename_log, filename_pov, filename_image):
    """Write ini file."""
    feature_set = bpy.context.preferences.addons[__package__].preferences.branch_feature_set_povray
    using_uberpov = (feature_set=='uberpov')
    #scene = bpy.data.scenes[0]
    scene = bpy.context.scene
    render = scene.render

    x = int(render.resolution_x * render.resolution_percentage * 0.01)
    y = int(render.resolution_y * render.resolution_percentage * 0.01)

    file = open(filename_ini, "w")
    file.write("Version=3.7\n")
    #write povray text stream to temporary file of same name with _log suffix
    #file.write("All_File='%s'\n" % filename_log)
    # DEBUG.OUT log if none specified:
    file.write("All_File=1\n")


    file.write("Input_File_Name='%s'\n" % filename_pov)
    file.write("Output_File_Name='%s'\n" % filename_image)

    file.write("Width=%d\n" % x)
    file.write("Height=%d\n" % y)

    # Border render.
    if render.use_border:
        file.write("Start_Column=%4g\n" % render.border_min_x)
        file.write("End_Column=%4g\n" % (render.border_max_x))

        file.write("Start_Row=%4g\n" % (1.0 - render.border_max_y))
        file.write("End_Row=%4g\n" % (1.0 - render.border_min_y))

    file.write("Bounding_Method=2\n")  # The new automatic BSP is faster in most scenes

    # Activated (turn this back off when better live exchange is done between the two programs
    # (see next comment)
    file.write("Display=1\n")
    file.write("Pause_When_Done=0\n")
    # PNG, with POV-Ray 3.7, can show background color with alpha. In the long run using the
    # POV-Ray interactive preview like bishop 3D could solve the preview for all formats.
    file.write("Output_File_Type=N\n")
    #file.write("Output_File_Type=T\n") # TGA, best progressive loading
    file.write("Output_Alpha=1\n")

    if scene.pov.antialias_enable:
        # method 2 (recursive) with higher max subdiv forced because no mipmapping in POV-Ray
        # needs higher sampling.
        # aa_mapping = {"5": 2, "8": 3, "11": 4, "16": 5}
        if using_uberpov:
            method = {"0": 1, "1": 2, "2": 3}
        else:
            method = {"0": 1, "1": 2, "2": 2}
        file.write("Antialias=on\n")
        file.write("Antialias_Depth=%d\n" % scene.pov.antialias_depth)
        file.write("Antialias_Threshold=%.3g\n" % scene.pov.antialias_threshold)
        if using_uberpov and scene.pov.antialias_method == '2':
            file.write("Sampling_Method=%s\n" % method[scene.pov.antialias_method])
            file.write("Antialias_Confidence=%.3g\n" % scene.pov.antialias_confidence)
        else:
            file.write("Sampling_Method=%s\n" % method[scene.pov.antialias_method])
        file.write("Antialias_Gamma=%.3g\n" % scene.pov.antialias_gamma)
        if scene.pov.jitter_enable:
            file.write("Jitter=on\n")
            file.write("Jitter_Amount=%3g\n" % scene.pov.jitter_amount)
        else:
            file.write("Jitter=off\n")  # prevent animation flicker

    else:
        file.write("Antialias=off\n")
    #print("ini file closed %s" % file.closed)
    file.close()
    #print("ini file closed %s" % file.closed)


class PovrayRender(bpy.types.RenderEngine):
    """Define the external renderer"""
    bl_idname = 'POVRAY_RENDER'
    bl_label = "Persitence Of Vision"
    bl_use_shading_nodes_custom = False
    DELAY = 0.5

    @staticmethod
    def _locate_binary():
        """Identify POV engine"""
        addon_prefs = bpy.context.preferences.addons[__package__].preferences

        # Use the system preference if its set.
        pov_binary = addon_prefs.filepath_povray
        if pov_binary:
            if os.path.exists(pov_binary):
                return pov_binary
            else:
                print("User Preferences path to povray %r NOT FOUND, checking $PATH" % pov_binary)

        # Windows Only
        # assume if there is a 64bit binary that the user has a 64bit capable OS
        if sys.platform[:3] == "win":
            import winreg
            win_reg_key = winreg.OpenKey(winreg.HKEY_CURRENT_USER,
                "Software\\POV-Ray\\v3.7\\Windows")
            win_home = winreg.QueryValueEx(win_reg_key, "Home")[0]

            # First try 64bits UberPOV
            pov_binary = os.path.join(win_home, "bin", "uberpov64.exe")
            if os.path.exists(pov_binary):
                return pov_binary

            # Then try 64bits POV
            pov_binary = os.path.join(win_home, "bin", "pvengine64.exe")
            if os.path.exists(pov_binary):
                return pov_binary

            # Then try 32bits UberPOV
            pov_binary = os.path.join(win_home, "bin", "uberpov32.exe")
            if os.path.exists(pov_binary):
                return pov_binary

            # Then try 32bits POV
            pov_binary = os.path.join(win_home, "bin", "pvengine.exe")
            if os.path.exists(pov_binary):
                return pov_binary

        # search the path all os's
        pov_binary_default = "povray"

        os_path_ls = os.getenv("PATH").split(':') + [""]

        for dir_name in os_path_ls:
            pov_binary = os.path.join(dir_name, pov_binary_default)
            if os.path.exists(pov_binary):
                return pov_binary
        return ""

    def _export(self, depsgraph, povPath, renderImagePath):
        """gather all necessary output files paths user defined and auto generated and export there"""
        import tempfile
        scene = bpy.context.scene
        if scene.pov.tempfiles_enable:
            self._temp_file_in = tempfile.NamedTemporaryFile(suffix=".pov", delete=False).name
            # PNG with POV 3.7, can show the background color with alpha. In the long run using the
            # POV-Ray interactive preview like bishop 3D could solve the preview for all formats.
            self._temp_file_out = tempfile.NamedTemporaryFile(suffix=".png", delete=False).name
            #self._temp_file_out = tempfile.NamedTemporaryFile(suffix=".tga", delete=False).name
            self._temp_file_ini = tempfile.NamedTemporaryFile(suffix=".ini", delete=False).name
            self._temp_file_log = os.path.join(tempfile.gettempdir(), "alltext.out")
        else:
            self._temp_file_in = povPath + ".pov"
            # PNG with POV 3.7, can show the background color with alpha. In the long run using the
            # POV-Ray interactive preview like bishop 3D could solve the preview for all formats.
            self._temp_file_out = renderImagePath + ".png"
            #self._temp_file_out = renderImagePath + ".tga"
            self._temp_file_ini = povPath + ".ini"
            logPath = bpy.path.abspath(scene.pov.scene_path).replace('\\', '/')
            self._temp_file_log = os.path.join(logPath, "alltext.out")
            '''
            self._temp_file_in = "/test.pov"
            # PNG with POV 3.7, can show the background color with alpha. In the long run using the
            # POV-Ray interactive preview like bishop 3D could solve the preview for all formats.
            self._temp_file_out = "/test.png"
            #self._temp_file_out = "/test.tga"
            self._temp_file_ini = "/test.ini"
            '''
        if scene.pov.text_block ==  "":
            def info_callback(txt):
                self.update_stats("", "POV-Ray 3.7: " + txt)

            # os.makedirs(user_dir, exist_ok=True)  # handled with previews
            os.makedirs(preview_dir, exist_ok=True)

            write_pov(self._temp_file_in, scene, info_callback)
        else:
            pass
    def _render(self, depsgraph):
        """Export necessary files and render image."""
        scene = bpy.context.scene
        try:
            os.remove(self._temp_file_out)  # so as not to load the old file
        except OSError:
            pass

        pov_binary = PovrayRender._locate_binary()
        if not pov_binary:
            print("POV-Ray 3.7: could not execute povray, possibly POV-Ray isn't installed")
            return False

        write_pov_ini(scene, self._temp_file_ini, self._temp_file_log, self._temp_file_in, self._temp_file_out)

        print ("***-STARTING-***")

        extra_args = []

        if scene.pov.command_line_switches != "":
            for newArg in scene.pov.command_line_switches.split(" "):
                extra_args.append(newArg)

        self._is_windows = False
        if sys.platform[:3] == "win":
            self._is_windows = True
            if"/EXIT" not in extra_args and not scene.pov.pov_editor:
                extra_args.append("/EXIT")
        else:
            # added -d option to prevent render window popup which leads to segfault on linux
            extra_args.append("-d")

        # Start Rendering!
        try:
            self._process = subprocess.Popen([pov_binary, self._temp_file_ini] + extra_args,
                                             stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
        except OSError:
            # TODO, report api
            print("POV-Ray 3.7: could not execute '%s'" % pov_binary)
            import traceback
            traceback.print_exc()
            print ("***-DONE-***")
            return False

        else:
            print("Engine ready!...")
            print("Command line arguments passed: " + str(extra_args))
            return True

        # Now that we have a valid process

    def _cleanup(self):
        """Delete temp files and unpacked ones"""
        for f in (self._temp_file_in, self._temp_file_ini, self._temp_file_out):
            for i in range(5):
                try:
                    os.unlink(f)
                    break
                except OSError:
                    # Wait a bit before retrying file might be still in use by Blender,
                    # and Windows does not know how to delete a file in use!
                    time.sleep(self.DELAY)
        for i in unpacked_images:
            for c in range(5):
                try:
                    os.unlink(i)
                    break
                except OSError:
                    # Wait a bit before retrying file might be still in use by Blender,
                    # and Windows does not know how to delete a file in use!
                    time.sleep(self.DELAY)
    def render(self, depsgraph):
        """Export necessary files from text editor and render image."""
        import tempfile
        scene = bpy.context.scene
        r = scene.render
        x = int(r.resolution_x * r.resolution_percentage * 0.01)
        y = int(r.resolution_y * r.resolution_percentage * 0.01)
        print("***INITIALIZING***")

        # This makes some tests on the render, returning True if all goes good, and False if