__init__.py

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#
#  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.
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#  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.
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#  along with this program; if not, write to the Free Software Foundation,
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# ##### END GPL LICENSE BLOCK #####

# <pep8 compliant>

"""Import, export and render to POV engines.

These engines can be POV-Ray or Uberpov but others too, since POV is a
Scene Description Language. The script has been split in as few files
as possible :

___init__.py :
    Initialize properties

update_files.py
    Update new variables to values from older API. This file needs an update

ui.py :
    Provide property buttons for the user to set up the variables

primitives.py :
    Display some POV native primitives in 3D view for input and output

shading.py
    Translate shading properties to declared textures at the top of a pov file

nodes.py
    Translate node trees to the pov file

df3.py
    Render smoke to *.df3 files

render.py :
    Translate geometry and UI properties (Blender and POV native) to the POV file


Along these essential files also coexist a few additional libraries to help make
Blender stand up to other POV IDEs such as povwin or QTPOV
    presets :
        Material (sss)
            apple.py ; chicken.py ; cream.py ; Ketchup.py ; marble.py ;
            potato.py ; skim_milk.py ; skin1.py ; skin2.py ; whole_milk.py
        Radiosity
            01_Debug.py ; 02_Fast.py ; 03_Normal.py ; 04_Two_Bounces.py ;
            05_Final.py ; 06_Outdoor_Low_Quality.py ; 07_Outdoor_High_Quality.py ;
            08_Outdoor(Sun)Light.py ; 09_Indoor_Low_Quality.py ;
            10_Indoor_High_Quality.py ;
        World
            01_Clear_Blue_Sky.py ; 02_Partly_Hazy_Sky.py ; 03_Overcast_Sky.py ;
            04_Cartoony_Sky.py ; 05_Under_Water.py ;
        Light
            01_(4800K)_Direct_Sun.py ;
            02_(5400K)_High_Noon_Sun.py ;
            03_(6000K)_Daylight_Window.py ;
            04_(6000K)_2500W_HMI_(Halogen_Metal_Iodide).py ;
            05_(4000K)_100W_Metal_Halide.py ;
            06_(3200K)_100W_Quartz_Halogen.py ;
            07_(2850K)_100w_Tungsten.py ;
            08_(2600K)_40w_Tungsten.py ;
            09_(5000K)_75W_Full_Spectrum_Fluorescent_T12.py ;
            10_(4300K)_40W_Vintage_Fluorescent_T12.py ;
            11_(5000K)_18W_Standard_Fluorescent_T8 ;
            12_(4200K)_18W_Cool_White_Fluorescent_T8.py ;
            13_(3000K)_18W_Warm_Fluorescent_T8.py ;
            14_(6500K)_54W_Grow_Light_Fluorescent_T5-HO.py ;
            15_(3200K)_40W_Induction_Fluorescent.py ;
            16_(2100K)_150W_High_Pressure_Sodium.py ;
            17_(1700K)_135W_Low_Pressure_Sodium.py ;
            18_(6800K)_175W_Mercury_Vapor.py ;
            19_(5200K)_700W_Carbon_Arc.py ;
            20_(6500K)_15W_LED_Spot.py ;
            21_(2700K)_7W_OLED_Panel.py ;
            22_(30000K)_40W_Black_Light_Fluorescent.py ;
            23_(30000K)_40W_Black_Light_Bulb.py;
            24_(1850K)_Candle.py
    templates:
        abyss.pov ; biscuit.pov ; bsp_Tango.pov ; chess2.pov ;
        cornell.pov ; diffract.pov ; diffuse_back.pov ; float5 ;
        gamma_showcase.pov ; grenadine.pov ; isocacti.pov ;
        mediasky.pov ; patio-radio.pov ; subsurface.pov ; wallstucco.pov
"""


bl_info = {
    "name": "Persistence of Vision",
    "author": "Campbell Barton, "
    "Maurice Raybaud, "
    "Leonid Desyatkov, "
    "Bastien Montagne, "
    "Constantin Rahn, "
    "Silvio Falcinelli",
    "version": (0, 1, 1),
    "blender": (2, 81, 0),
    "location": "Render Properties > Render Engine > Persistence of Vision",
    "description": "Persistence of Vision integration for blender",
    "doc_url": "{BLENDER_MANUAL_URL}/addons/render/povray.html",
    "category": "Render",
    "warning": "Under active development, seeking co-maintainer(s)",
}

if "bpy" in locals():
    import importlib

    importlib.reload(ui)
    importlib.reload(nodes)
    importlib.reload(render)
    importlib.reload(shading)
    importlib.reload(primitives)
    importlib.reload(update_files)

else:
    import bpy
    from bpy.utils import register_class, unregister_class
    # import addon_utils  # To use some other addons
    import nodeitems_utils  # for Nodes
    from nodeitems_utils import NodeCategory, NodeItem  # for Nodes
    from bl_operators.presets import AddPresetBase
    from bpy.types import (
        AddonPreferences,
        PropertyGroup,
        NodeSocket,
    )

    from bpy.props import (
        FloatVectorProperty,
        StringProperty,
        BoolProperty,
        IntProperty,
        FloatProperty,
        EnumProperty,
        PointerProperty,
        CollectionProperty,
    )
    from . import ui, render, update_files


def string_strip_hyphen(name):

    """Remove hyphen characters from a string to avoid POV errors"""

    return name.replace("-", "")

def pov_context_tex_datablock(context):
    """Texture context type recreated as deprecated in blender 2.8"""

    idblock = context.brush
    if idblock and context.scene.texture_context == 'OTHER':
        return idblock

    # idblock = bpy.context.active_object.active_material
    idblock = context.view_layer.objects.active.active_material
    if idblock and context.scene.texture_context == 'MATERIAL':
        return idblock

    idblock = context.world
    if idblock and context.scene.texture_context == 'WORLD':
        return idblock

    idblock = context.light
    if idblock and context.scene.texture_context == 'LIGHT':
        return idblock

    if context.particle_system and context.scene.texture_context == 'PARTICLES':
        idblock = context.particle_system.settings

    return idblock

    idblock = context.line_style
    if idblock and context.scene.texture_context == 'LINESTYLE':
        return idblock

def brush_texture_update(self, context):

    """Brush texture rolldown must show active slot texture props"""
    idblock = pov_context_tex_datablock(context)
    if idblock is not None:
        #mat = context.view_layer.objects.active.active_material
        idblock = pov_context_tex_datablock(context)
        slot = idblock.pov_texture_slots[idblock.pov.active_texture_index]
        tex = slot.texture

        if tex:
            # Switch paint brush to active texture so slot and settings remain contextual
            bpy.context.tool_settings.image_paint.brush.texture = bpy.data.textures[tex]
            bpy.context.tool_settings.image_paint.brush.mask_texture = bpy.data.textures[tex]

def active_texture_name_from_uilist(self, context):

    idblock = pov_context_tex_datablock(context)
    #mat = context.view_layer.objects.active.active_material
    if idblock is not None:
        index = idblock.pov.active_texture_index
        name = idblock.pov_texture_slots[index].name
        newname = idblock.pov_texture_slots[index].texture
        tex = bpy.data.textures[name]
        tex.name = newname
        idblock.pov_texture_slots[index].name = newname


def active_texture_name_from_search(self, context):
    """Texture rolldown to change the data linked by an existing texture"""
    idblock = pov_context_tex_datablock(context)
    #mat = context.view_layer.objects.active.active_material
    if idblock is not None:
        index = idblock.pov.active_texture_index
        slot = idblock.pov_texture_slots[index]
        name = slot.texture_search

    try:
        tex = bpy.data.textures[name]
        slot.name = name
        slot.texture = name
        # Switch paint brush to this texture so settings remain contextual
        #bpy.context.tool_settings.image_paint.brush.texture = tex
        #bpy.context.tool_settings.image_paint.brush.mask_texture = tex
    except:
        pass



###############################################################################
# Scene POV properties.
###############################################################################
class RenderPovSettingsScene(PropertyGroup):

    """Declare scene level properties controllable in UI and translated to POV"""

    # Linux SDL-window enable
    sdl_window_enable: BoolProperty(
        name="Enable SDL window",
        description="Enable the SDL window in Linux OS",
        default=True,
    )
    # File Options
    text_block: StringProperty(
        name="Text Scene Name",
        description="Name of POV scene to use. "
        "Set when clicking Run to render current text only",
        maxlen=1024,
    )
    tempfiles_enable: BoolProperty(
        name="Enable Tempfiles",
        description="Enable the OS-Tempfiles. Otherwise set the path where"
        " to save the files",
        default=True,
    )
    pov_editor: BoolProperty(
        name="POV editor",
        description="Don't Close POV editor after rendering (Overridden"
        " by /EXIT command)",
        default=False,
    )
    deletefiles_enable: BoolProperty(
        name="Delete files",
        description="Delete files after rendering. "
        "Doesn't work with the image",
        default=True,
    )
    scene_name: StringProperty(
        name="Scene Name",
        description="Name of POV scene to create. Empty name will use "
        "the name of the blend file",
        maxlen=1024,
    )
    scene_path: StringProperty(
        name="Export scene path",
        # Bug in POV-Ray RC3
        # description="Path to directory where the exported scene "
        # "(POV and INI) is created",
        description="Path to directory where the files are created",
        maxlen=1024,
        subtype="DIR_PATH",
    )
    renderimage_path: StringProperty(
        name="Rendered image path",
        description="Full path to directory where the rendered image is "
        "saved",
        maxlen=1024,
        subtype="DIR_PATH",
    )
    list_lf_enable: BoolProperty(
        name="LF in lists",
        description="Enable line breaks in lists (vectors and indices). "
        "Disabled: lists are exported in one line",
        default=True,
    )

    # Not a real pov option, just to know if we should write
    radio_enable: BoolProperty(
        name="Enable Radiosity",
        description="Enable POV radiosity calculation",
        default=True,
    )

    radio_display_advanced: BoolProperty(
        name="Advanced Options",
        description="Show advanced options",
        default=False,
    )

    media_enable: BoolProperty(
        name="Enable Media",
        description="Enable POV atmospheric media",
        default=False,
    )

    media_samples: IntProperty(
        name="Samples",
        description="Number of samples taken from camera to first object "
        "encountered along ray path for media calculation",
        min=1,
        max=100,
        default=35,
    )

    media_scattering_type: EnumProperty(
        name="Scattering Type",
        description="Scattering model",
        items=(
            (
                '1',
                "1 Isotropic",
                "The simplest form of scattering because"
                " it is independent of direction."
            ),
            (
                '2',
                "2 Mie haze ",
                "For relatively small particles such as "
                "minuscule water droplets of fog, cloud "
                "particles, and particles responsible "
                "for the polluted sky. In this model the"
                " scattering is extremely directional in"
                " the forward direction i.e. the amount "
                "of scattered light is largest when the "
                "incident light is anti-parallel to the "
                "viewing direction (the light goes "
                "directly to the viewer). It is smallest"
                " when the incident light is parallel to"
                " the viewing direction. "
            ),
            (
                '3',
                "3 Mie murky",
                "Like haze but much more directional"
            ),
            (
                '4',
                "4 Rayleigh",
                "For extremely small particles such as "
                "molecules of the air. The amount of "
                "scattered light depends on the incident"
                " light angle. It is largest when the "
                "incident light is parallel or "
                "anti-parallel to the viewing direction "
                "and smallest when the incident light is "
                "perpendicular to viewing direction."
            ),
            (
                '5',
                "5 Henyey-Greenstein",
                "The default eccentricity value "
                "of zero defines isotropic "
                "scattering while positive "
                "values lead to scattering in "
                "the direction of the light and "
                "negative values lead to "
                "scattering in the opposite "
                "direction of the light. Larger "
                "values of e (or smaller values "
                "in the negative case) increase "
                "the directional property of the"
                " scattering."
            )
        ),
        default='1',
    )

    media_diffusion_scale: FloatProperty(
        name="Scale",
        description="Scale factor of Media Diffusion Color",
        precision=6, step=0.00000001, min=0.000000001, max=1.0,
        default=(1.0),
    )

    media_diffusion_color: FloatVectorProperty(
        name="Media Diffusion Color",
        description="The atmospheric media color",
        precision=4, step=0.01, min=0, soft_max=1,
        default=(0.001, 0.001, 0.001),
        options={'ANIMATABLE'},
        subtype='COLOR',
    )

    media_absorption_scale: FloatProperty(
        name="Scale",
        description="Scale factor of Media Absorption Color. "
        "use 1/depth of media volume in meters",
        precision=6,
        step=0.000001,
        min=0.000000001,
        max=1.0,
        default=(0.00002),
    )

    media_absorption_color: FloatVectorProperty(
        name="Media Absorption Color",
        description="The atmospheric media absorption color",
        precision=4, step=0.01, min=0, soft_max=1,
        default=(0.0, 0.0, 0.0),
        options={'ANIMATABLE'},
        subtype='COLOR',
    )

    media_eccentricity: FloatProperty(
        name="Media Eccenticity Factor",
        description="Positive values lead"
        " to scattering in the direction of the light and negative "
        "values lead to scattering in the opposite direction of the "
        "light. Larger values of e (or smaller values in the negative"
        " case) increase the directional property of the scattering",
        precision=2,
        step=0.01,
        min=-1.0,
        max=1.0,
        default=(0.0),
        options={'ANIMATABLE'},
    )

    baking_enable: BoolProperty(
        name="Enable Baking",
        description="Enable POV texture baking",
        default=False
    )

    indentation_character: EnumProperty(
        name="Indentation",
        description="Select the indentation type",
        items=(
            ('NONE', "None", "No indentation"),
            ('TAB', "Tabs", "Indentation with tabs"),
            ('SPACE', "Spaces", "Indentation with spaces")
        ),
        default='SPACE'
    )

    indentation_spaces: IntProperty(
        name="Quantity of spaces",
        description="The number of spaces for indentation",
        min=1,
        max=10,
        default=4,
    )

    comments_enable: BoolProperty(
        name="Enable Comments",
        description="Add comments to pov file",
        default=True,
    )

    # Real pov options
    command_line_switches: StringProperty(
        name="Command Line Switches",
        description="Command line switches consist of a + (plus) or - "
        "(minus) sign, followed by one or more alphabetic "
        "characters and possibly a numeric value",
        maxlen=500,
    )

    antialias_enable: BoolProperty(
        name="Anti-Alias", description="Enable Anti-Aliasing",
        default=True,
    )

    antialias_method: EnumProperty(
        name="Method",
        description="AA-sampling method. Type 1 is an adaptive, "
        "non-recursive, super-sampling method. Type 2 is an "
        "adaptive and recursive super-sampling method. Type 3 "
        "is a stochastic halton based super-sampling method",
        items=(
            ("0", "non-recursive AA", "Type 1 Sampling in POV"),
            ("1", "recursive AA", "Type 2 Sampling in POV"),
            ("2", "stochastic AA", "Type 3 Sampling in POV")
        ),
        default="1",
    )

    antialias_confidence: FloatProperty(
        name="Antialias Confidence",
        description="how surely the computed color "
        "of a given pixel is indeed"
        "within the threshold error margin",
        min=0.0001,
        max=1.0000,
        default=0.9900,
        precision=4
    )

    antialias_depth: IntProperty(
        name="Antialias Depth",
        description="Depth of pixel for sampling",
        min=1,
        max=9,
        default=3
    )

    antialias_threshold: FloatProperty(
        name="Antialias Threshold",
        description="Tolerance for sub-pixels",
        min=0.0,
        max=1.0,
        soft_min=0.05,
        soft_max=0.5,
        default=0.03,
    )

    jitter_enable: BoolProperty(
        name="Jitter",
        description="Enable Jittering. Adds noise into the sampling "
        "process (it should be avoided to use jitter in "
        "animation)",
        default=False,
    )

    jitter_amount: FloatProperty(
        name="Jitter Amount",
        description="Amount of jittering",
        min=0.0,
        max=1.0,
        soft_min=0.01,
        soft_max=1.0,
        default=1.0,
    )

    antialias_gamma: FloatProperty(
        name="Antialias Gamma",
        description="POV-Ray compares gamma-adjusted values for super "
        "sampling. Antialias Gamma sets the Gamma before "
        "comparison",
        min=0.0,
        max=5.0,
        soft_min=0.01,
        soft_max=2.5,
        default=2.5,
    )

    alpha_mode: EnumProperty(
        name="Alpha",
        description="Representation of alpha information in the RGBA pixels",
        items=(
            ("SKY", "Sky", "Transparent pixels are filled with sky color"),
            (
            "TRANSPARENT",
            "Transparent",
            "Transparent, World background is transparent with premultiplied alpha",
            ),
        ),
        default="SKY",
    )

    use_shadows: BoolProperty(
        name="Shadows",
        description="Calculate shadows while rendering",
        default=True,
    )

    max_trace_level: IntProperty(
        name="Max Trace Level",
        description="Number of reflections/refractions allowed on ray "
        "path",
        min=1,
        max=256,
        default=5
    )

    adc_bailout_enable: BoolProperty(
        name="Enable",
        description="",
        default=False,
    )

    adc_bailout: FloatProperty(
        name="ADC Bailout",
        description="Adaptive Depth Control (ADC) to stop computing additional"
            "reflected or refracted rays when their contribution is insignificant."
            "The default value is 1/255, or approximately 0.0039, since a change "
            "smaller than that could not be visible in a 24 bit image. Generally "
            "this value is fine and should be left alone."
            "Setting adc_bailout to 0 will disable ADC, relying completely on "
            "max_trace_level to set an upper limit on the number of rays spawned. ",
        min=0.0,
        max=1000.0,
        default=0.00392156862745,
        precision=3
    )

    ambient_light_enable: BoolProperty(
        name="Enable",
        description="",
        default=False,
    )

    ambient_light: FloatVectorProperty(
        name="Ambient Light",
        description="Ambient light is used to simulate the effect of inter-diffuse reflection",
        precision=4, step=0.01, min=0, soft_max=1,
        default=(1, 1, 1), options={'ANIMATABLE'}, subtype='COLOR',
    )
    global_settings_advanced: BoolProperty(
        name="Advanced",
        description="",
        default=False,
    )

    irid_wavelength_enable: BoolProperty(
        name="Enable",
        description="",
        default=False,
    )

    irid_wavelength: FloatVectorProperty(
        name="Irid Wavelength",
        description=(
            "Iridescence calculations depend upon the dominant "
            "wavelengths of the primary colors of red, green and blue light"
        ),
        precision=4,
        step=0.01,
        min=0,
        soft_max=1,
        default=(0.25,0.18,0.14),
        options={'ANIMATABLE'},
        subtype='COLOR'
    )
    # Deprecated (autodetected in pov3.8):
    # charset: EnumProperty(
        # name="Charset",
        # description="This allows you to specify the assumed character set of all text strings",
        # items=(
            # ("ascii", "ASCII", ""),
            # ("utf8", "UTF-8", ""),
            # ("sys", "SYS", "")
        # ),
        # default="utf8",
    # )

    max_intersections_enable: BoolProperty(
        name="Enable",
        description="",
        default=False,
    )

    max_intersections: IntProperty(
        name="Max Intersections",
        description="POV-Ray uses a set of internal stacks to collect ray/object intersection points",
        min=2,
        max=1024,
        default=64,
    )

    number_of_waves_enable: BoolProperty(
        name="Enable",
        description="",
        default=False,
    )

    number_of_waves: IntProperty(
        name="Number Waves",
        description=(
            "The waves and ripples patterns are generated by summing a series of waves, "
            "each with a slightly different center and size"
        ),
        min=1,
        max=10,
        default=1000,
    )

    noise_generator_enable: BoolProperty(
        name="Enable",
        description="",
        default=False,
    )

    noise_generator: IntProperty(
        name="Noise Generator",
        description="There are three noise generators implemented",
        min=1,
        max=3,
        default=2,
    )

    ########################### PHOTONS #######################################
    photon_enable: BoolProperty(
        name="Photons",
        description="Enable global photons",
        default=False,
    )

    photon_enable_count: BoolProperty(
        name="Spacing / Count",
        description="Enable count photons",
        default=False,
    )

    photon_count: IntProperty(
        name="Count",
        description="Photons count",
        min=1,
        max=100000000,
        default=20000
    )

    photon_spacing: FloatProperty(
        name="Spacing",
        description="Average distance between photons on surfaces. half "
        "this get four times as many surface photons",
        min=0.001,
        max=1.000,
        soft_min=0.001,
        soft_max=1.000,
        precision=3,
        default=0.005,
    )

    photon_max_trace_level: IntProperty(
        name="Max Trace Level",
        description="Number of reflections/refractions allowed on ray "
        "path",
        min=1,
        max=256,
        default=5
    )

    photon_adc_bailout: FloatProperty(
        name="ADC Bailout",
        description="The adc_bailout for photons. Use adc_bailout = "
        "0.01 / brightest_ambient_object for good results",
        min=0.0,
        max=1000.0,
        soft_min=0.0,
        soft_max=1.0,
        precision=3,
        default=0.1,
    )

    photon_gather_min: IntProperty(
        name="Gather Min", description="Minimum number of photons gathered"
        "for each point",
        min=1, max=256, default=20
    )

    photon_gather_max: IntProperty(
        name="Gather Max", description="Maximum number of photons gathered for each point",
        min=1, max=256, default=100
    )

    photon_map_file_save_load: EnumProperty(
        name="Operation",
        description="Load or Save photon map file",
        items=(
            ("NONE", "None", ""),
            ("save", "Save", ""),
            ("load", "Load", "")
        ),
        default="NONE",
    )

    photon_map_filename: StringProperty(
        name="Filename",
        description="",
        maxlen=1024
    )

    photon_map_dir: StringProperty(
        name="Directory",
        description="",
        maxlen=1024,
        subtype="DIR_PATH",
    )

    photon_map_file: StringProperty(
        name="File",
        description="",
        maxlen=1024,
        subtype="FILE_PATH"
    )

    #########RADIOSITY########
    radio_adc_bailout: FloatProperty(
        name="ADC Bailout",
        description="The adc_bailout for radiosity rays. Use "
        "adc_bailout = 0.01 / brightest_ambient_object for good results",
        min=0.0,
        max=1000.0,
        soft_min=0.0,
        soft_max=1.0,
        default=0.0039,
        precision=4,
    )

    radio_always_sample: BoolProperty(
        name="Always Sample",
        description="Only use the data from the pretrace step and not gather "
        "any new samples during the final radiosity pass",
        default=False,
    )

    radio_brightness: FloatProperty(
        name="Brightness",
        description="Amount objects are brightened before being returned "
        "upwards to the rest of the system",
        min=0.0, max=1000.0, soft_min=0.0, soft_max=10.0, default=1.0
    )

    radio_count: IntProperty(
        name="Ray Count",
        description="Number of rays for each new radiosity value to be calculated "
        "(halton sequence over 1600)",
        min=1, max=10000, soft_max=1600, default=35
    )

    radio_error_bound: FloatProperty(
        name="Error Bound",
        description="One of the two main speed/quality tuning values, "
        "lower values are more accurate",
        min=0.0, max=1000.0, soft_min=0.1, soft_max=10.0, default=10.0
    )

    radio_gray_threshold: FloatProperty(
        name="Gray Threshold",
        description="One of the two main speed/quality tuning values, "
        "lower values are more accurate",
        min=0.0, max=1.0, soft_min=0, soft_max=1, default=0.0
    )

    radio_low_error_factor: FloatProperty(
        name="Low Error Factor",
        description="Just enough samples is slightly blotchy. Low error changes error "
        "tolerance for less critical last refining pass",
        min=0.000001, max=1.0, soft_min=0.000001, soft_max=1.0, default=0.5
    )

    radio_media: BoolProperty(
        name="Media",
        description="Radiosity estimation can be affected by media",
        default=True,
    )

    radio_subsurface: BoolProperty(
        name="Subsurface",
        description="Radiosity estimation can be affected by Subsurface Light Transport",
        default=False,
    )

    radio_minimum_reuse: FloatProperty(
        name="Minimum Reuse",
        description="Fraction of the screen width which sets the minimum radius of reuse "
        "for each sample point (At values higher than 2% expect errors)",
        min=0.0, max=1.0, soft_min=0.1, soft_max=0.1, default=0.015, precision=3
    )

    radio_maximum_reuse: FloatProperty(
        name="Maximum Reuse",
        description="The maximum reuse parameter works in conjunction with, and is similar to that of minimum reuse, "
        "the only difference being that it is an upper bound rather than a lower one",
        min=0.0, max=1.0,default=0.2, precision=3
    )

    radio_nearest_count: IntProperty(
        name="Nearest Count",
        description="Number of old ambient values blended together to "
        "create a new interpolated value",
        min=1, max=20, default=1
    )

    radio_normal: BoolProperty(
        name="Normals",
        description="Radiosity estimation can be affected by normals",
        default=False,
    )

    radio_recursion_limit: IntProperty(
        name="Recursion Limit",
        description="how many recursion levels are used to calculate "
        "the diffuse inter-reflection",
        min=1, max=20, default=1
    )

    radio_pretrace_start: FloatProperty(
        name="Pretrace Start",
        description="Fraction of the screen width which sets the size of the "
        "blocks in the mosaic preview first pass",
        min=0.005, max=1.00, soft_min=0.02, soft_max=1.0, default=0.04
    )
    # XXX TODO set automatically to  pretrace_end = 8 / max (image_width, image_height)
    # for non advanced mode
    radio_pretrace_end: FloatProperty(
        name="Pretrace End",
        description="Fraction of the screen width which sets the size of the blocks "
        "in the mosaic preview last pass",
        min=0.000925, max=1.00, soft_min=0.01, soft_max=1.00, default=0.004, precision=3
    )

###############################################################################
# Material POV properties.
###############################################################################
class MaterialTextureSlot(PropertyGroup):
    """Declare material texture slot level properties for UI and translated to POV."""

    bl_idname="pov_texture_slots",
    bl_description="Texture_slots from Blender-2.79",

    # Adding a "real" texture datablock as property is not possible
    # (or at least not easy through a dynamically populated EnumProperty).
    # That's why we'll use a prop_search() UILayout function in ui.py.
    # So we'll assign the name of the needed texture datablock to the below StringProperty.
    texture : StringProperty(update=active_texture_name_from_uilist)
    # and use another temporary StringProperty to change the linked data
    texture_search : StringProperty(
        name="",
        update = active_texture_name_from_search,
        description = "Browse Texture to be linked",
    )

    alpha_factor: FloatProperty(
        name="Alpha",
        description="Amount texture affects alpha",
        default = 1.0,
    )

    ambient_factor: FloatProperty(
        name="",
        description="Amount texture affects ambient",
        default = 1.0,
    )

    bump_method: EnumProperty(
        name="",
        description="Method to use for bump mapping",
        items=(
            ("BUMP_ORIGINAL", "Bump Original", ""),
            ("BUMP_COMPATIBLE", "Bump Compatible", ""),
            ("BUMP_DEFAULT", "Bump Default", ""),
            ("BUMP_BEST_QUALITY", "Bump Best Quality", "")
        ),
        default="BUMP_ORIGINAL",
    )

    bump_objectspace: EnumProperty(
        name="",
        description="Space to apply bump mapping in",
        items=(
            ("BUMP_VIEWSPACE", "Bump Viewspace", ""),
            ("BUMP_OBJECTSPACE", "Bump Objectspace", ""),
            ("BUMP_TEXTURESPACE", "Bump Texturespace", "")
        ),
        default="BUMP_VIEWSPACE",
    )

    density_factor: FloatProperty(
        name="",
        description="Amount texture affects density",
        default = 1.0,
    )

    diffuse_color_factor: FloatProperty(
        name="",
        description="Amount texture affects diffuse color",
        default = 1.0,
    )

    diffuse_factor: FloatProperty(
        name="",
        description="Amount texture affects diffuse reflectivity",
        default = 1.0,
    )

    displacement_factor: FloatProperty(
        name="",
        description="Amount texture displaces the surface",
        default = 0.2,
    )

    emission_color_factor: FloatProperty(