render.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.
#
# ##### END GPL LICENSE BLOCK #####

# <pep8 compliant>

import bpy
import subprocess
import os
import sys
import time
from math import atan, pi, degrees, sqrt
import re

##############################SF###########################
##############find image texture


def imageFormat(imgF):
    ext = {
        'JPG': "jpeg",
        'JPEG': "jpeg",
        'GIF': "gif",
        'TGA': "tga",
        'IFF': "iff",
        'PPM': "ppm",
        'PNG': "png",
        'SYS': "sys",
        'TIFF': "tiff",
        'TIF': "tiff",
        'EXR': "exr",  # POV3.7 Only!
        'HDR': "hdr",  # POV3.7 Only! --MR
    }.get(os.path.splitext(imgF)[-1].upper(), "")

    if not ext:
        print(" WARNING: texture image format not supported ")

    return ext


def imgMap(ts):
    image_map = ""
    if ts.mapping == 'FLAT':
        image_map = "map_type 0 "
    elif ts.mapping == 'SPHERE':
        image_map = "map_type 1 "  # map_type 7 in megapov
    elif ts.mapping == 'TUBE':
        image_map = "map_type 2 "

    ## map_type 3 and 4 in development (?)
    ## for POV-Ray, currently they just seem to default back to Flat (type 0)
    #elif ts.mapping=="?":
    #    image_map = " map_type 3 "
    #elif ts.mapping=="?":
    #    image_map = " map_type 4 "
    if ts.texture.use_interpolation:
        image_map += " interpolate 2 "
    if ts.texture.extension == 'CLIP':
        image_map += " once "
    #image_map += "}"
    #if ts.mapping=='CUBE':
    #    image_map+= "warp { cubic } rotate <-90,0,180>"
    # no direct cube type mapping. Though this should work in POV 3.7
    # it doesn't give that good results(best suited to environment maps?)
    #if image_map == "":
    #    print(" No texture image  found ")
    return image_map


def imgMapBG(wts):
    image_mapBG = ""
    # texture_coords refers to the mapping of world textures:
    if wts.texture_coords == 'VIEW':
        image_mapBG = " map_type 0 "
    elif wts.texture_coords == 'ANGMAP':
        image_mapBG = " map_type 1 "
    elif wts.texture_coords == 'TUBE':
        image_mapBG = " map_type 2 "

    if wts.texture.use_interpolation:
        image_mapBG += " interpolate 2 "
    if wts.texture.extension == 'CLIP':
        image_mapBG += " once "
    #image_mapBG += "}"
    #if wts.mapping == 'CUBE':
    #   image_mapBG += "warp { cubic } rotate <-90,0,180>"
    # no direct cube type mapping. Though this should work in POV 3.7
    # it doesn't give that good results(best suited to environment maps?)
    #if image_mapBG == "":
    #    print(" No background texture image  found ")
    return image_mapBG


def path_image(image):
    return bpy.path.abspath(image.filepath, library=image.library)

# end find image texture
# -----------------------------------------------------------------------------


def string_strip_hyphen(name):
    return name.replace("-", "")


def safety(name, Level):
    # safety string name material
    #
    # Level=1 is for texture with No specular nor Mirror reflection
    # Level=2 is for texture with translation of spec and mir levels
    # for when no map influences them
    # Level=3 is for texture with Maximum Spec and Mirror

    try:
        if int(name) > 0:
            prefix = "shader"
    except:
        prefix = ""
    prefix = "shader_"
    name = string_strip_hyphen(name)
    if Level == 2:
        return prefix + name
    elif Level == 1:
        return prefix + name + "0"  # used for 0 of specular map
    elif Level == 3:
        return prefix + name + "1"  # used for 1 of specular map


##############end safety string name material
##############################EndSF###########################

def is_renderable(scene, ob):
    return (ob.is_visible(scene) and not ob.hide_render)


def renderable_objects(scene):
    return [ob for ob in scene.objects if is_renderable(scene, ob)]


tabLevel = 0


def write_pov(filename, scene=None, info_callback=None):
    import mathutils
    #file = filename
    file = open(filename, "w")

    # Only for testing
    if not scene:
        scene = bpy.data.scenes[0]

    render = scene.render
    world = scene.world
    global_matrix = mathutils.Matrix.Rotation(-pi / 2.0, 4, 'X')

    def setTab(tabtype, spaces):
        TabStr = ""
        if tabtype == '0':
            TabStr = ""
        elif tabtype == '1':
            TabStr = "\t"
        elif tabtype == '2':
            TabStr = spaces * " "
        return TabStr

    tab = setTab(scene.pov.indentation_character, scene.pov.indentation_spaces)

    def tabWrite(str_o):
        if not scene.pov.tempfiles_enable:
            global tabLevel
            brackets = str_o.count("{") - str_o.count("}") + str_o.count("[") - str_o.count("]")
            if brackets < 0:
                tabLevel = tabLevel + brackets
            if tabLevel < 0:
                print("Indentation Warning: tabLevel = %s" % tabLevel)
                tabLevel = 0
            if tabLevel >= 1:
                file.write("%s" % tab * tabLevel)
            file.write(str_o)
            if brackets > 0:
                tabLevel = tabLevel + brackets
        else:
            file.write(str_o)

    def uniqueName(name, nameSeq):

        if name not in nameSeq:
            name = string_strip_hyphen(name)
            return name

        name_orig = name
        i = 1
        while name in nameSeq:
            name = "%s_%.3d" % (name_orig, i)
            i += 1
        name = string_strip_hyphen(name)
        return name

    def writeMatrix(matrix):
        tabWrite("matrix <%.6f, %.6f, %.6f,  %.6f, %.6f, %.6f,  %.6f, %.6f, %.6f,  %.6f, %.6f, " \
                 "%.6f>\n" % (matrix[0][0], matrix[0][1], matrix[0][2], matrix[1][0], matrix[1][1],
                              matrix[1][2], matrix[2][0], matrix[2][1], matrix[2][2], matrix[3][0],
                              matrix[3][1], matrix[3][2]))

    def MatrixAsPovString(matrix):
        sMatrix = ("matrix <%.6f, %.6f, %.6f,  %.6f, %.6f, %.6f,  %.6f, %.6f, %.6f,  %.6f, %.6f, " \
                   "%.6f>\n" % (matrix[0][0], matrix[0][1], matrix[0][2], matrix[1][0], matrix[1][1],
                                matrix[1][2], matrix[2][0], matrix[2][1], matrix[2][2], matrix[3][0],
                                matrix[3][1], matrix[3][2]))
        return sMatrix

    def writeObjectMaterial(material, ob):

        # DH - modified some variables to be function local, avoiding RNA write
        # this should be checked to see if it is functionally correct

        # Commented out: always write IOR to be able to use it for SSS, Fresnel reflections...
        #if material and material.transparency_method == 'RAYTRACE':
        if material:
            # But there can be only one!
            if material.subsurface_scattering.use:  # SSS IOR get highest priority
                tabWrite("interior {\n")
                tabWrite("ior %.6f\n" % material.subsurface_scattering.ior)
            # Then the raytrace IOR taken from raytrace transparency properties and used for
            # reflections if IOR Mirror option is checked.
            elif material.pov.mirror_use_IOR:
                tabWrite("interior {\n")
                tabWrite("ior %.6f\n" % material.raytrace_transparency.ior)
            else:
                tabWrite("interior {\n")
                tabWrite("ior %.6f\n" % material.raytrace_transparency.ior)

            pov_fake_caustics = False
            pov_photons_refraction = False
            pov_photons_reflection = False

            if material.pov.photons_reflection:
                pov_photons_reflection = True
            if material.pov.refraction_type == "0":
                pov_fake_caustics = False
                pov_photons_refraction = False
            elif material.pov.refraction_type == "1":
                pov_fake_caustics = True
                pov_photons_refraction = False
            elif material.pov.refraction_type == "2":
                pov_fake_caustics = False
                pov_photons_refraction = True

            # If only Raytrace transparency is set, its IOR will be used for refraction, but user
            # can set up 'un-physical' fresnel reflections in raytrace mirror parameters.
            # Last, if none of the above is specified, user can set up 'un-physical' fresnel
            # reflections in raytrace mirror parameters. And pov IOR defaults to 1.
            if material.pov.caustics_enable:
                if pov_fake_caustics:
                    tabWrite("caustics %.3g\n" % material.pov.fake_caustics_power)
                if pov_photons_refraction:
                    # Default of 1 means no dispersion
                    tabWrite("dispersion %.6f\n" % material.pov.photons_dispersion)
                    tabWrite("dispersion_samples %.d\n" % material.pov.photons_dispersion_samples)
            #TODO
            # Other interior args
            if material.use_transparency and material.transparency_method == 'RAYTRACE':
                # fade_distance
                # In Blender this value has always been reversed compared to what tooltip says.
                # 100.001 rather than 100 so that it does not get to 0
                # which deactivates the feature in POV
                tabWrite("fade_distance %.3g\n" % \
                         (100.001 - material.raytrace_transparency.depth_max))
                # fade_power
                tabWrite("fade_power %.3g\n" % material.raytrace_transparency.falloff)
                # fade_color
                tabWrite("fade_color <%.3g, %.3g, %.3g>\n" % material.pov.interior_fade_color[:])

            # (variable) dispersion_samples (constant count for now)
            tabWrite("}\n")

            tabWrite("photons{")
            if not ob.pov.collect_photons:
                tabWrite("collect off\n")
                tabWrite("target %.3g\n" % ob.pov.spacing_multiplier)
            if pov_photons_refraction:
                tabWrite("refraction on\n")
            if pov_photons_reflection:
                tabWrite("reflection on\n")
            tabWrite("}\n")

    materialNames = {}
    DEF_MAT_NAME = "Default"

    def writeMaterial(material):
        # Assumes only called once on each material
        if material:
            name_orig = material.name
        else:
            name_orig = DEF_MAT_NAME

        name = materialNames[name_orig] = uniqueName(bpy.path.clean_name(name_orig), materialNames)
        comments = scene.pov.comments_enable

        ##################
        # Several versions of the finish: Level conditions are variations for specular/Mirror
        # texture channel map with alternative finish of 0 specular and no mirror reflection.
        # Level=1 Means No specular nor Mirror reflection
        # Level=2 Means translation of spec and mir levels for when no map influences them
        # Level=3 Means Maximum Spec and Mirror

        def povHasnoSpecularMaps(Level):
            if Level == 1:
                tabWrite("#declare %s = finish {" % safety(name, Level=1))
                if not scene.pov.tempfiles_enable and comments:
                    file.write("  //No specular nor Mirror reflection\n")
                else:
                    tabWrite("\n")
            elif Level == 2:
                tabWrite("#declare %s = finish {" % safety(name, Level=2))
                if not scene.pov.tempfiles_enable and comments:
                    file.write("  //translation of spec and mir levels for when no map " \
                               "influences them\n")
                else:
                    tabWrite("\n")
            elif Level == 3:
                tabWrite("#declare %s = finish {" % safety(name, Level=3))
                if not scene.pov.tempfiles_enable and comments:
                    file.write("  //Maximum Spec and Mirror\n")
                else:
                    tabWrite("\n")

            if material:
                # POV-Ray 3.7 now uses two diffuse values respectively for front and back shading
                # (the back diffuse is like blender translucency)
                frontDiffuse = material.diffuse_intensity
                backDiffuse = material.translucency

                if material.pov.conserve_energy:

                    #Total should not go above one
                    if (frontDiffuse + backDiffuse) <= 1.0:
                        pass
                    elif frontDiffuse == backDiffuse:
                        # Try to respect the user's 'intention' by comparing the two values but
                        # bringing the total back to one.
                        frontDiffuse = backDiffuse = 0.5
                    # Let the highest value stay the highest value.
                    elif frontDiffuse > backDiffuse:
                        # clamps the sum below 1
                        backDiffuse = min(backDiffuse, (1.0 - frontDiffuse))
                    else:
                        frontDiffuse = min(frontDiffuse, (1.0 - backDiffuse))

                # map hardness between 0.0 and 1.0
                roughness = ((1.0 - ((material.specular_hardness - 1.0) / 510.0)))
                ## scale from 0.0 to 0.1
                roughness *= 0.1
                # add a small value because 0.0 is invalid.
                roughness += (1.0 / 511.0)

                ################################Diffuse Shader######################################
                # Not used for Full spec (Level=3) of the shader.
                if material.diffuse_shader == 'OREN_NAYAR' and Level != 3:
                    # Blender roughness is what is generally called oren nayar Sigma,
                    # and brilliance in POV-Ray.
                    tabWrite("brilliance %.3g\n" % (0.9 + material.roughness))

                if material.diffuse_shader == 'TOON' and Level != 3:
                    tabWrite("brilliance %.3g\n" % (0.01 + material.diffuse_toon_smooth * 0.25))
                    # Lower diffuse and increase specular for toon effect seems to look better
                    # in POV-Ray.
                    frontDiffuse *= 0.5

                if material.diffuse_shader == 'MINNAERT' and Level != 3:
                    #tabWrite("aoi %.3g\n" % material.darkness)
                    pass  # let's keep things simple for now
                if material.diffuse_shader == 'FRESNEL' and Level != 3:
                    #tabWrite("aoi %.3g\n" % material.diffuse_fresnel_factor)
                    pass  # let's keep things simple for now
                if material.diffuse_shader == 'LAMBERT' and Level != 3:
                    # trying to best match lambert attenuation by that constant brilliance value
                    tabWrite("brilliance 1.8\n")

                if Level == 2:
                    ###########################Specular Shader######################################
                    # No difference between phong and cook torrence in blender HaHa!
                    if (material.specular_shader == 'COOKTORR' or
                        material.specular_shader == 'PHONG'):
                        tabWrite("phong %.3g\n" % (material.specular_intensity))
                        tabWrite("phong_size %.3g\n" % (material.specular_hardness / 2 + 0.25))

                    # POV-Ray 'specular' keyword corresponds to a Blinn model, without the ior.
                    elif material.specular_shader == 'BLINN':
                        # Use blender Blinn's IOR just as some factor for spec intensity
                        tabWrite("specular %.3g\n" % (material.specular_intensity *
                                                      (material.specular_ior / 4.0)))
                        tabWrite("roughness %.3g\n" % roughness)
                        #Could use brilliance 2(or varying around 2 depending on ior or factor) too.

                    elif material.specular_shader == 'TOON':
                        tabWrite("phong %.3g\n" % (material.specular_intensity * 2.0))
                        # use extreme phong_size
                        tabWrite("phong_size %.3g\n" % (0.1 + material.specular_toon_smooth / 2.0))

                    elif material.specular_shader == 'WARDISO':
                        # find best suited default constant for brilliance Use both phong and
                        # specular for some values.
                        tabWrite("specular %.3g\n" % (material.specular_intensity /
                                                      (material.specular_slope + 0.0005)))
                        # find best suited default constant for brilliance Use both phong and
                        # specular for some values.
                        tabWrite("roughness %.4g\n" % (0.0005 + material.specular_slope / 10.0))
                        # find best suited default constant for brilliance Use both phong and
                        # specular for some values.
                        tabWrite("brilliance %.4g\n" % (1.8 - material.specular_slope * 1.8))

                ####################################################################################
                elif Level == 1:
                    tabWrite("specular 0\n")
                elif Level == 3:
                    tabWrite("specular 1\n")
                tabWrite("diffuse %.3g %.3g\n" % (frontDiffuse, backDiffuse))

                tabWrite("ambient %.3g\n" % material.ambient)
                # POV-Ray blends the global value
                #tabWrite("ambient rgb <%.3g, %.3g, %.3g>\n" % \
                #         tuple([c*material.ambient for c in world.ambient_color]))
                tabWrite("emission %.3g\n" % material.emit)  # New in POV-Ray 3.7

                #POV-Ray just ignores roughness if there's no specular keyword
                #tabWrite("roughness %.3g\n" % roughness)

                if material.pov.conserve_energy:
                    # added for more realistic shading. Needs some checking to see if it
                    # really works. --Maurice.
                    tabWrite("conserve_energy\n")

                # 'phong 70.0 '
                if Level != 1:
                    if material.raytrace_mirror.use:
                        raytrace_mirror = material.raytrace_mirror
                        if raytrace_mirror.reflect_factor:
                            tabWrite("reflection {\n")
                            tabWrite("rgb <%.3g, %.3g, %.3g>" % material.mirror_color[:])
                            if material.pov.mirror_metallic:
                                tabWrite("metallic %.3g" % (raytrace_mirror.reflect_factor))
                            if material.pov.mirror_use_IOR:  # WORKING ?
                                # Removed from the line below: gives a more physically correct
                                # material but needs proper IOR. --Maurice
                                tabWrite("fresnel 1 ")
                            tabWrite("falloff %.3g exponent %.3g} " % \
                                     (raytrace_mirror.fresnel, raytrace_mirror.fresnel_factor))

                if material.subsurface_scattering.use:
                    subsurface_scattering = material.subsurface_scattering
                    tabWrite("subsurface { <%.3g, %.3g, %.3g>, <%.3g, %.3g, %.3g> }\n" % (
                             sqrt(subsurface_scattering.radius[0]) * 1.5,
                             sqrt(subsurface_scattering.radius[1]) * 1.5,
                             sqrt(subsurface_scattering.radius[2]) * 1.5,
                             1.0 - subsurface_scattering.color[0],
                             1.0 - subsurface_scattering.color[1],
                             1.0 - subsurface_scattering.color[2])
                            )

                if material.pov.irid_enable:
                    tabWrite("irid { %.4g thickness %.4g turbulence %.4g }" % \
                             (material.pov.irid_amount, material.pov.irid_thickness,
                              material.pov.irid_turbulence))

            else:
                tabWrite("diffuse 0.8\n")
                tabWrite("phong 70.0\n")

                #tabWrite("specular 0.2\n")

            # This is written into the object
            '''
            if material and material.transparency_method=='RAYTRACE':
                'interior { ior %.3g} ' % material.raytrace_transparency.ior
            '''

            #tabWrite("crand 1.0\n") # Sand granyness
            #tabWrite("metallic %.6f\n" % material.spec)
            #tabWrite("phong %.6f\n" % material.spec)
            #tabWrite("phong_size %.6f\n" % material.spec)
            #tabWrite("brilliance %.6f " % (material.specular_hardness/256.0) # Like hardness

            tabWrite("}\n\n")

        # Level=2 Means translation of spec and mir levels for when no map influences them
        povHasnoSpecularMaps(Level=2)

        if material:
            special_texture_found = False
            for t in material.texture_slots:
                if(t and t.texture.type == 'IMAGE' and t.use and t.texture.image and
                   (t.use_map_specular or t.use_map_raymir or t.use_map_normal or t.use_map_alpha)):
                    special_texture_found = True
                    continue  # Some texture found

            if special_texture_found:
                # Level=1 Means No specular nor Mirror reflection
                povHasnoSpecularMaps(Level=1)

                # Level=3 Means Maximum Spec and Mirror
                povHasnoSpecularMaps(Level=3)

    def exportCamera():
        camera = scene.camera

        # DH disabled for now, this isn't the correct context
        active_object = None  # bpy.context.active_object # does not always work  MR
        matrix = global_matrix * camera.matrix_world
        focal_point = camera.data.dof_distance

        # compute resolution
        Qsize = float(render.resolution_x) / float(render.resolution_y)
        tabWrite("#declare camLocation  = <%.6f, %.6f, %.6f>;\n" % \
                 (matrix[3][0], matrix[3][1], matrix[3][2]))
        tabWrite("#declare camLookAt = <%.6f, %.6f, %.6f>;\n" % \
                 tuple([degrees(e) for e in matrix.to_3x3().to_euler()]))

        tabWrite("camera {\n")
        if scene.pov.baking_enable and active_object and active_object.type == 'MESH':
            tabWrite("mesh_camera{ 1 3\n")  # distribution 3 is what we want here
            tabWrite("mesh{%s}\n" % active_object.name)
            tabWrite("}\n")
            tabWrite("location <0,0,.01>")
            tabWrite("direction <0,0,-1>")
        # Using standard camera otherwise
        else:
            tabWrite("location  <0, 0, 0>\n")
            tabWrite("look_at  <0, 0, -1>\n")
            tabWrite("right <%s, 0, 0>\n" % - Qsize)
            tabWrite("up <0, 1, 0>\n")
            tabWrite("angle  %f\n" % (360.0 * atan(16.0 / camera.data.lens) / pi))

            tabWrite("rotate  <%.6f, %.6f, %.6f>\n" % \
                     tuple([degrees(e) for e in matrix.to_3x3().to_euler()]))
            tabWrite("translate <%.6f, %.6f, %.6f>\n" % (matrix[3][0], matrix[3][1], matrix[3][2]))
            if camera.data.pov.dof_enable and focal_point != 0:
                tabWrite("aperture %.3g\n" % camera.data.pov.dof_aperture)
                tabWrite("blur_samples %d %d\n" % \
                         (camera.data.pov.dof_samples_min, camera.data.pov.dof_samples_max))
                tabWrite("variance 1/%d\n" % camera.data.pov.dof_variance)
                tabWrite("confidence %.3g\n" % camera.data.pov.dof_confidence)
                tabWrite("focal_point <0, 0, %f>\n" % focal_point)
        tabWrite("}\n")

    def exportLamps(lamps):
        # Incremented after each lamp export to declare its target
        # currently used for Fresnel diffuse shader as their slope vector:
        global lampCount
        lampCount = 0
        # Get all lamps
        for ob in lamps:
            lamp = ob.data

            matrix = global_matrix * ob.matrix_world

            # Colour is modified by energy #muiltiplie by 2 for a better match --Maurice
            color = tuple([c * lamp.energy * 2.0 for c in lamp.color])

            tabWrite("light_source {\n")
            tabWrite("< 0,0,0 >\n")
            tabWrite("color rgb<%.3g, %.3g, %.3g>\n" % color)

            if lamp.type == 'POINT':
                pass
            elif lamp.type == 'SPOT':
                tabWrite("spotlight\n")

                # Falloff is the main radius from the centre line
                tabWrite("falloff %.2f\n" % (degrees(lamp.spot_size) / 2.0))  # 1 TO 179 FOR BOTH
                tabWrite("radius %.6f\n" % \
                         ((degrees(lamp.spot_size) / 2.0) * (1.0 - lamp.spot_blend)))

                # Blender does not have a tightness equivilent, 0 is most like blender default.
                tabWrite("tightness 0\n")  # 0:10f

                tabWrite("point_at  <0, 0, -1>\n")
            elif lamp.type == 'SUN':
                tabWrite("parallel\n")
                tabWrite("point_at  <0, 0, -1>\n")  # *must* be after 'parallel'

            elif lamp.type == 'AREA':
                tabWrite("area_illumination\n")
                tabWrite("fade_distance %.6f\n" % (lamp.distance / 2.0))
                # Area lights have no falloff type, so always use blenders lamp quad equivalent
                # for those?
                tabWrite("fade_power %d\n" % 2)
                size_x = lamp.size
                samples_x = lamp.shadow_ray_samples_x
                if lamp.shape == 'SQUARE':
                    size_y = size_x
                    samples_y = samples_x
                else:
                    size_y = lamp.size_y
                    samples_y = lamp.shadow_ray_samples_y

                tabWrite("area_light <%.6f,0,0>,<0,%.6f,0> %d, %d\n" % \
                         (size_x, size_y, samples_x, samples_y))
                if lamp.shadow_ray_sample_method == 'CONSTANT_JITTERED':
                    if lamp.use_jitter:
                        tabWrite("jitter\n")
                else:
                    tabWrite("adaptive 1\n")
                    tabWrite("jitter\n")

            # HEMI never has any shadow_method attribute
            if(not scene.render.use_shadows or lamp.type == 'HEMI' or
               (lamp.type != 'HEMI' and lamp.shadow_method == 'NOSHADOW')):
                tabWrite("shadowless\n")

            # Sun shouldn't be attenuated. Hemi and area lights have no falloff attribute so they
            # are put to type 2 attenuation a little higher above.
            if lamp.type not in {'SUN', 'AREA', 'HEMI'}:
                tabWrite("fade_distance %.6f\n" % (lamp.distance / 2.0))
                if lamp.falloff_type == 'INVERSE_SQUARE':
                    tabWrite("fade_power %d\n" % 2)  # Use blenders lamp quad equivalent
                elif lamp.falloff_type == 'INVERSE_LINEAR':
                    tabWrite("fade_power %d\n" % 1)  # Use blenders lamp linear
                # supposing using no fade power keyword would default to constant, no attenuation.
                elif lamp.falloff_type == 'CONSTANT':
                    pass
                # Using Custom curve for fade power 3 for now.
                elif lamp.falloff_type == 'CUSTOM_CURVE':
                    tabWrite("fade_power %d\n" % 4)

            writeMatrix(matrix)

            tabWrite("}\n")

            lampCount += 1

            # v(A,B) rotates vector A about origin by vector B.
            file.write("#declare lampTarget%s= vrotate(<%.4g,%.4g,%.4g>,<%.4g,%.4g,%.4g>);\n" % \
                       (lampCount, -(ob.location.x), -(ob.location.y), -(ob.location.z),
                        ob.rotation_euler.x, ob.rotation_euler.y, ob.rotation_euler.z))

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

    def exportMeta(metas):

        # TODO - blenders 'motherball' naming is not supported.

        if not scene.pov.tempfiles_enable and scene.pov.comments_enable and len(metas) >= 1:
            file.write("//--Blob objects--\n\n")

        for ob in metas:
            meta = ob.data

            # important because no elements will break parsing.
            elements = [elem for elem in meta.elements if elem.type in {'BALL', 'ELLIPSOID'}]

            if elements:
                tabWrite("blob {\n")
                tabWrite("threshold %.4g\n" % meta.threshold)
                importance = ob.pov.importance_value

                try:
                    material = meta.materials[0]  # lame! - blender cant do enything else.
                except:
                    material = None

                for elem in elements:
                    loc = elem.co

                    stiffness = elem.stiffness
                    if elem.use_negative:
                        stiffness = - stiffness

                    if elem.type == 'BALL':

                        tabWrite("sphere { <%.6g, %.6g, %.6g>, %.4g, %.4g }\n" % \
                                 (loc.x, loc.y, loc.z, elem.radius, stiffness))

                        # After this wecould do something simple like...
                        # 	"pigment {Blue} }"
                        # except we'll write the color

                    elif elem.type == 'ELLIPSOID':
                        # location is modified by scale
                        tabWrite("sphere { <%.6g, %.6g, %.6g>, %.4g, %.4g }\n" % \
                                 (loc.x / elem.size_x, loc.y / elem.size_y, loc.z / elem.size_z,
                                  elem.radius, stiffness))
                        tabWrite("scale <%.6g, %.6g, %.6g> \n" % \
                                 (elem.size_x, elem.size_y, elem.size_z))

                if material:
                    diffuse_color = material.diffuse_color
                    trans = 1.0 - material.alpha
                    if material.use_transparency and material.transparency_method == 'RAYTRACE':
                        povFilter = material.raytrace_transparency.filter * (1.0 - material.alpha)
                        trans = (1.0 - material.alpha) - povFilter
                    else:
                        povFilter = 0.0

                    material_finish = materialNames[material.name]

                    tabWrite("pigment {rgbft<%.3g, %.3g, %.3g, %.3g, %.3g>} \n" % \
                             (diffuse_color[0], diffuse_color[1], diffuse_color[2],
                              povFilter, trans))
                    tabWrite("finish {%s}\n" % safety(material_finish, Level=2))

                else:
                    tabWrite("pigment {rgb<1 1 1>} \n")
                    # Write the finish last.
                    tabWrite("finish {%s}\n" % (safety(DEF_MAT_NAME, Level=2)))

                writeObjectMaterial(material, ob)

                writeMatrix(global_matrix * ob.matrix_world)
                #Importance for radiosity sampling added here:
                tabWrite("radiosity { \n")
                tabWrite("importance %3g \n" % importance)
                tabWrite("}\n")

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

                if not scene.pov.tempfiles_enable and scene.pov.comments_enable and len(metas) >= 1:
                    file.write("\n")

#    objectNames = {}
    DEF_OBJ_NAME = "Default"

    def exportMeshes(scene, sel):
#        obmatslist = []
#        def hasUniqueMaterial():
#            # Grab materials attached to object instances ...
#            if hasattr(ob, 'material_slots'):
#                for ms in ob.material_slots:
#                    if ms.material != None and ms.link == 'OBJECT':
#                        if ms.material in obmatslist:
#                            return False
#                        else:
#                            obmatslist.append(ms.material)
#                            return True
#        def hasObjectMaterial(ob):
#            # Grab materials attached to object instances ...
#            if hasattr(ob, 'material_slots'):
#                for ms in ob.material_slots:
#                    if ms.material != None and ms.link == 'OBJECT':
#                        # If there is at least one material slot linked to the object
#                        # and not the data (mesh), always create a new, “private” data instance.
#                        return True
#            return False
        # For objects using local material(s) only!
        # This is a mapping between a tuple (dataname, materialnames, ...), and the POV dataname.
        # As only objects using:
        #     * The same data.
        #     * EXACTLY the same materials, in EXACTLY the same sockets.
        # ... can share a same instance in POV export.
        obmats2data = {}

        def checkObjectMaterials(ob, name, dataname):
            if hasattr(ob, 'material_slots'):
                has_local_mats = False
                key = [dataname]
                for ms in ob.material_slots:
                    if ms.material != None:
                        key.append(ms.material.name)
                        if ms.link == 'OBJECT' and not has_local_mats:
                            has_local_mats = True
                    else:
                        # Even if the slot is empty, it is important to grab it...
                        key.append("")
                if has_local_mats:
                    # If this object uses local material(s), lets find if another object
                    # using the same data and exactly the same list of materials
                    # (in the same slots) has already been processed...
                    # Note that here also, we use object name as new, unique dataname for Pov.
                    key = tuple(key)  # Lists are not hashable...
                    if key not in obmats2data:
                        obmats2data[key] = name
                    return obmats2data[key]
            return None

        data_ref = {}

        def store(scene, ob, name, dataname, matrix):
            # The Object needs to be written at least once but if its data is
            # already in data_ref this has already been done.
            # This func returns the “povray” name of the data, or None
            # if no writing is needed.
            if ob.is_modified(scene, 'RENDER'):
                # Data modified.
                # Create unique entry in data_ref by using object name
                # (always unique in Blender) as data name.
                data_ref[name] = [(name, MatrixAsPovString(matrix))]
                return name
            # Here, we replace dataname by the value returned by checkObjectMaterials, only if
            # it is not evaluated to False (i.e. only if the object uses some local material(s)).
            dataname = checkObjectMaterials(ob, name, dataname) or dataname
            if dataname in data_ref:
                # Data already known, just add the object instance.
                data_ref[dataname].append((name, MatrixAsPovString(matrix)))
                # No need to write data
                return None
            else:
                # Data not yet processed, create a new entry in data_ref.
                data_ref[dataname] = [(name, MatrixAsPovString(matrix))]
                return dataname

        ob_num = 0
        for ob in sel:
            ob_num += 1

            # XXX I moved all those checks here, as there is no need to compute names
            #     for object we won’t export here!
            if ob.type in {'LAMP', 'CAMERA', 'EMPTY', 'META', 'ARMATURE', 'LATTICE'}:
                continue

            try:
                me = ob.to_mesh(scene, True, 'RENDER')
            except:
                # happens when curves cant be made into meshes because of no-data
                continue

            importance = ob.pov.importance_value
            me_materials = me.materials
            me_faces = me.faces[:]

            if not me or not me_faces:
                continue

#############################################
            # Generating a name for object just like materials to be able to use it
            # (baking for now or anything else).
            # XXX I don’t understand that – if we are here, sel if a non-empty iterable,
            #     so this condition is always True, IMO -- mont29
            if sel:
                name_orig = "OB" + ob.name
                dataname_orig = "DATA" + ob.data.name
            else:
                name_orig = DEF_OBJ_NAME
                dataname_orig = DEF_OBJ_NAME
            name = string_strip_hyphen(bpy.path.clean_name(name_orig))
            dataname = string_strip_hyphen(bpy.path.clean_name(dataname_orig))
##            for slot in ob.material_slots:
##                if slot.material != None and slot.link == 'OBJECT':
##                    obmaterial = slot.material

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

            if info_callback:
                info_callback("Object %2.d of %2.d (%s)" % (ob_num, len(sel), ob.name))

            #if ob.type != 'MESH':
            #	continue
            # me = ob.data

            matrix = global_matrix * ob.matrix_world
            povdataname = store(scene, ob, name, dataname, matrix)
            if povdataname is None:
                print("This is an instance")
                continue

            print("Writing Down First Occurence")

            try:
                uv_layer = me.uv_textures.active.data
            except AttributeError:
                uv_layer = None

            try:
                vcol_layer = me.vertex_colors.active.data
            except AttributeError:
                vcol_layer = None

            faces_verts = [f.vertices[:] for f in me_faces]
            faces_normals = [f.normal[:] for f in me_faces]
            verts_normals = [v.normal[:] for v in me.vertices]

            # quads incur an extra face
            quadCount = sum(1 for f in faces_verts if len(f) == 4)

            # Use named declaration to allow reference e.g. for baking. MR
            file.write("\n")
            tabWrite("#declare %s =\n" % povdataname)
            tabWrite("mesh2 {\n")
            tabWrite("vertex_vectors {\n")
            tabWrite("%d" % len(me.vertices))  # vert count

            tabStr = tab * tabLevel
            for v in me.vertices:
                if not scene.pov.tempfiles_enable and scene.pov.list_lf_enable:
                    file.write(",\n")
                    file.write(tabStr + "<%.6f, %.6f, %.6f>" % v.co[:])  # vert count
                else:
                    file.write(", ")
                    file.write("<%.6f, %.6f, %.6f>" % v.co[:])  # vert count
                #tabWrite("<%.6f, %.6f, %.6f>" % v.co[:])  # vert count
            file.write("\n")
            tabWrite("}\n")

            # Build unique Normal list
            uniqueNormals = {}
            for fi, f in enumerate(me_faces):
                fv = faces_verts[fi]
                # [-1] is a dummy index, use a list so we can modify in place
                if f.use_smooth:  # Use vertex normals
                    for v in fv:
                        key = verts_normals[v]
                        uniqueNormals[key] = [-1]
                else:  # Use face normal
                    key = faces_normals[fi]
                    uniqueNormals[key] = [-1]

            tabWrite("normal_vectors {\n")
            tabWrite("%d" % len(uniqueNormals))  # vert count
            idx = 0
            tabStr = tab * tabLevel
            for no, index in uniqueNormals.items():
                if not scene.pov.tempfiles_enable and scene.pov.list_lf_enable:
                    file.write(",\n")
                    file.write(tabStr + "<%.6f, %.6f, %.6f>" % no)  # vert count
                else:
                    file.write(", ")
                    file.write("<%.6f, %.6f, %.6f>" % no)  # vert count
                index[0] = idx
                idx += 1
            file.write("\n")
            tabWrite("}\n")

            # Vertex colours
            vertCols = {}  # Use for material colours also.

            if uv_layer:
                # Generate unique UV's
                uniqueUVs = {}

                for fi, uv in enumerate(uv_layer):

                    if len(faces_verts[fi]) == 4:
                        uvs = uv.uv1, uv.uv2, uv.uv3, uv.uv4
                    else:
                        uvs = uv.uv1, uv.uv2, uv.uv3

                    for uv in uvs:
                        uniqueUVs[uv[:]] = [-1]

                tabWrite("uv_vectors {\n")
                #print unique_uvs
                tabWrite("%d" % len(uniqueUVs))  # vert count
                idx = 0
                tabStr = tab * tabLevel
                for uv, index in uniqueUVs.items():
                    if not scene.pov.tempfiles_enable and scene.pov.list_lf_enable:
                        file.write(",\n")
                        file.write(tabStr + "<%.6f, %.6f>" % uv)
                    else:
                        file.write(", ")
                        file.write("<%.6f, %.6f>" % uv)
                    index[0] = idx
                    idx += 1
                '''
                else:
                    # Just add 1 dummy vector, no real UV's
                    tabWrite('1') # vert count
                    file.write(',\n\t\t<0.0, 0.0>')
                '''
                file.write("\n")
                tabWrite("}\n")

            if me.vertex_colors:

                for fi, f in enumerate(me_faces):
                    material_index = f.material_index
                    material = me_materials[material_index]

                    if material and material.use_vertex_color_paint:

                        col = vcol_layer[fi]

                        if len(faces_verts[fi]) == 4:
                            cols = col.color1, col.color2, col.color3, col.color4
                        else:
                            cols = col.color1, col.color2, col.color3

                        for col in cols:
                            key = col[0], col[1], col[2], material_index  # Material index!
                            vertCols[key] = [-1]

                    else:
                        if material:
                            diffuse_color = material.diffuse_color[:]
                            key = diffuse_color[0], diffuse_color[1], diffuse_color[2], \
                                  material_index
                            vertCols[key] = [-1]