render_povray/shading.py

   1 # SPDX-FileCopyrightText: 2015-2022 Blender Foundation
   2 #
   3 # SPDX-License-Identifier: GPL-2.0-or-later
   4
   5 """Translate complex shaders to exported POV textures."""
   6
   7 import bpy
   8
   9
  10 def write_object_material_interior(file, material, ob, tab_write):
  11     """Translate some object level material from Blender UI (VS data level)
  12
  13     to POV interior{} syntax and write it to exported file.
  14     This is called in model_all.objects_loop
  15     """
  16     # DH - modified some variables to be function local, avoiding RNA write
  17     # this should be checked to see if it is functionally correct
  18
  19     # Commented out: always write IOR to be able to use it for SSS, Fresnel reflections...
  20     # if material and material.pov.transparency_method == 'RAYTRACE':
  21     if not material:
  22         return
  23     # implicit if material:
  24     # But there can be only one ior!
  25     if material.pov_subsurface_scattering.use:  # SSS IOR get highest priority
  26         tab_write(file, "interior {\n")
  27         tab_write(file, "ior %.6f\n" % material.pov_subsurface_scattering.ior)
  28     # Then the raytrace IOR taken from raytrace transparency properties and used for
  29     # reflections if IOR Mirror option is checked.
  30     elif material.pov.mirror_use_IOR or material.pov.transparency_method != "Z_TRANSPARENCY":
  31         tab_write(file, "interior {\n")
  32         tab_write(file, "ior %.6f\n" % material.pov_raytrace_transparency.ior)
  33     else:
  34         tab_write(file, "interior {\n")
  35         tab_write(file, "ior 1.0\n")
  36
  37     pov_fake_caustics = False
  38     pov_photons_refraction = False
  39     pov_photons_reflection = bool(material.pov.photons_reflection)
  40     if not material.pov.refraction_caustics:
  41         pov_fake_caustics = False
  42         pov_photons_refraction = False
  43     elif material.pov.refraction_type == "1":
  44         pov_fake_caustics = True
  45         pov_photons_refraction = False
  46     elif material.pov.refraction_type == "2":
  47         pov_fake_caustics = False
  48         pov_photons_refraction = True
  49
  50     # If only Raytrace transparency is set, its IOR will be used for refraction, but user
  51     # can set up 'un-physical' fresnel reflections in raytrace mirror parameters.
  52     # Last, if none of the above is specified, user can set up 'un-physical' fresnel
  53     # reflections in raytrace mirror parameters. And pov IOR defaults to 1.
  54     if material.pov.caustics_enable:
  55         if pov_fake_caustics:
  56             tab_write(file, "caustics %.3g\n" % material.pov.fake_caustics_power)
  57         if pov_photons_refraction:
  58             # Default of 1 means no dispersion
  59             tab_write(file, "dispersion %.6f\n" % material.pov.photons_dispersion)
  60             tab_write(file, "dispersion_samples %.d\n" % material.pov.photons_dispersion_samples)
  61     # TODO
  62     # Other interior args
  63     if material.pov.use_transparency and material.pov.transparency_method == "RAYTRACE":
  64         # fade_distance
  65         # In Blender this value has always been reversed compared to what tooltip says.
  66         # 100.001 rather than 100 so that it does not get to 0
  67         # which deactivates the feature in POV
  68         tab_write(
  69             file, "fade_distance %.3g\n" % (100.001 - material.pov_raytrace_transparency.depth_max)
  70         )
  71         # fade_power
  72         tab_write(file, "fade_power %.3g\n" % material.pov_raytrace_transparency.falloff)
  73         # fade_color
  74         tab_write(file, "fade_color <%.3g, %.3g, %.3g>\n" % material.pov.interior_fade_color[:])
  75
  76     # (variable) dispersion_samples (constant count for now)
  77     tab_write(file, "}\n")
  78     if material.pov.photons_reflection or material.pov.refraction_type == "2":
  79         tab_write(file, "photons{")
  80         tab_write(file, "target %.3g\n" % ob.pov.spacing_multiplier)
  81         if not ob.pov.collect_photons:
  82             tab_write(file, "collect off\n")
  83         if pov_photons_refraction:
  84             tab_write(file, "refraction on\n")
  85         if pov_photons_reflection:
  86             tab_write(file, "reflection on\n")
  87         tab_write(file, "}\n")
  88
  89
  90 def write_material(
  91     file,
  92     using_uberpov,
  93     DEF_MAT_NAME,
  94     tab_write,
  95     comments,
  96     unique_name,
  97     material_names_dictionary,
  98     material,
  99 ):
 100     """Translate Blender material to POV texture{} block and write in exported file."""
 101     # Assumes only called once on each material
 102
 103     from .render import safety
 104
 105     if material:
 106         name_orig = material.name
 107         name = material_names_dictionary[name_orig] = unique_name(
 108             bpy.path.clean_name(name_orig), material_names_dictionary
 109         )
 110         # If saturation(.s) is not zero, then color is not grey, and has a tint
 111         colored_specular_found = (material.pov.specular_color.s > 0.0) and (
 112             material.pov.diffuse_shader != "MINNAERT"
 113         )
 114     else:
 115         name = name_orig = DEF_MAT_NAME
 116
 117     ##################
 118     # Several versions of the finish: ref_level_bound conditions are variations for specular/Mirror
 119     # texture channel map with alternative finish of 0 specular and no mirror reflection.
 120     # ref_level_bound=1 Means No specular nor Mirror reflection
 121     # ref_level_bound=2 Means translation of spec and mir levels for when no map influences them
 122     # ref_level_bound=3 Means Maximum Spec and Mirror
 123
 124     def pov_has_no_specular_maps(file, ref_level_bound):
 125         """Translate Blender specular map influence to POV finish map trick and write to file."""
 126         if ref_level_bound == 1:
 127             if comments:
 128                 tab_write(file, "//--No specular nor Mirror reflection--\n")
 129             else:
 130                 tab_write(file, "\n")
 131             tab_write(file, "#declare %s = finish {\n" % safety(name, ref_level_bound=1))
 132
 133         elif ref_level_bound == 2:
 134             if comments:
 135                 tab_write(
 136                     file,
 137                     "//--translation of spec and mir levels for when no map " "influences them--\n",
 138                 )
 139             else:
 140                 tab_write(file, "\n")
 141             tab_write(file, "#declare %s = finish {\n" % safety(name, ref_level_bound=2))
 142
 143         elif ref_level_bound == 3:
 144             if comments:
 145                 tab_write(file, "//--Maximum Spec and Mirror--\n")
 146             else:
 147                 tab_write(file, "\n")
 148             tab_write(file, "#declare %s = finish {\n" % safety(name, ref_level_bound=3))
 149         if material:
 150             # POV-Ray 3.7 now uses two diffuse values respectively for front and back shading
 151             # (the back diffuse is like blender translucency)
 152             front_diffuse = material.pov.diffuse_intensity
 153             back_diffuse = material.pov.translucency
 154
 155             if material.pov.conserve_energy:
 156
 157                 # Total should not go above one
 158                 if (front_diffuse + back_diffuse) <= 1.0:
 159                     pass
 160                 elif front_diffuse == back_diffuse:
 161                     # Try to respect the user's 'intention' by comparing the two values but
 162                     # bringing the total back to one.
 163                     front_diffuse = back_diffuse = 0.5
 164                 # Let the highest value stay the highest value.
 165                 elif front_diffuse > back_diffuse:
 166                     # clamps the sum below 1
 167                     back_diffuse = min(back_diffuse, (1.0 - front_diffuse))
 168                 else:
 169                     front_diffuse = min(front_diffuse, (1.0 - back_diffuse))
 170
 171             # map hardness between 0.0 and 1.0
 172             roughness = 1.0 - ((material.pov.specular_hardness - 1.0) / 510.0)
 173             ## scale from 0.0 to 0.1
 174             roughness *= 0.1
 175             # add a small value because 0.0 is invalid.
 176             roughness += 1.0 / 511.0
 177
 178             # ------------------------------ Diffuse Shader ------------------------------ #
 179             # Not used for Full spec (ref_level_bound=3) of the shader.
 180             if material.pov.diffuse_shader == "OREN_NAYAR" and ref_level_bound != 3:
 181                 # Blender roughness is what is generally called oren nayar Sigma,
 182                 # and brilliance in POV-Ray.
 183                 tab_write(file, "brilliance %.3g\n" % (0.9 + material.roughness))
 184
 185             if material.pov.diffuse_shader == "TOON" and ref_level_bound != 3:
 186                 tab_write(file, "brilliance %.3g\n" % (0.01 + material.diffuse_toon_smooth * 0.25))
 187                 # Lower diffuse and increase specular for toon effect seems to look better
 188                 # in POV-Ray.
 189                 front_diffuse *= 0.5
 190
 191             if material.pov.diffuse_shader == "MINNAERT" and ref_level_bound != 3:
 192                 # tab_write(file, "aoi %.3g\n" % material.pov.darkness)
 193                 pass  # let's keep things simple for now
 194             if material.pov.diffuse_shader == "FRESNEL" and ref_level_bound != 3:
 195                 # tab_write(file, "aoi %.3g\n" % material.pov.diffuse_fresnel_factor)
 196                 pass  # let's keep things simple for now
 197             if material.pov.diffuse_shader == "LAMBERT" and ref_level_bound != 3:
 198                 # trying to best match lambert attenuation by that constant brilliance value
 199                 tab_write(file, "brilliance 1\n")
 200
 201             if ref_level_bound == 2:
 202                 # ------------------------------ Specular Shader ------------------------------ #
 203                 # No difference between phong and cook torrence in blender HaHa!
 204                 if material.pov.specular_shader in ["COOKTORR", "PHONG"]:
 205                     tab_write(file, "phong %.3g\n" % material.pov.specular_intensity)
 206                     tab_write(file, "phong_size %.3g\n" % (material.pov.specular_hardness / 3.14))
 207
 208                 # POV-Ray 'specular' keyword corresponds to a Blinn model, without the ior.
 209                 elif material.pov.specular_shader == "BLINN":
 210                     # Use blender Blinn's IOR just as some factor for spec intensity
 211                     tab_write(
 212                         file,
 213                         "specular %.3g\n"
 214                         % (material.pov.specular_intensity * (material.pov.specular_ior / 4.0)),
 215                     )
 216                     tab_write(file, "roughness %.3g\n" % roughness)
 217                     # Could use brilliance 2(or varying around 2 depending on ior or factor) too.
 218
 219                 elif material.pov.specular_shader == "TOON":
 220                     tab_write(file, "phong %.3g\n" % (material.pov.specular_intensity * 2.0))
 221                     # use extreme phong_size
 222                     tab_write(
 223                         file, "phong_size %.3g\n" % (0.1 + material.pov.specular_toon_smooth / 2.0)
 224                     )
 225
 226                 elif material.pov.specular_shader == "WARDISO":
 227                     # find best suited default constant for brilliance Use both phong and
 228                     # specular for some values.
 229                     tab_write(
 230                         file,
 231                         "specular %.3g\n"
 232                         % (
 233                             material.pov.specular_intensity / (material.pov.specular_slope + 0.0005)
 234                         ),
 235                     )
 236                     # find best suited default constant for brilliance Use both phong and
 237                     # specular for some values.
 238                     tab_write(
 239                         file, "roughness %.4g\n" % (0.0005 + material.pov.specular_slope / 10.0)
 240                     )
 241                     # find best suited default constant for brilliance Use both phong and
 242                     # specular for some values.
 243                     tab_write(file, "brilliance %.4g\n" % (1.8 - material.pov.specular_slope * 1.8))
 244
 245             # -------------------------------------------------------------------------------- #
 246             elif ref_level_bound == 1:
 247                 if material.pov.specular_shader in ["COOKTORR", "PHONG"]:
 248                     tab_write(file, "phong 0\n")  # %.3g\n" % (material.pov.specular_intensity/5))
 249                     tab_write(file, "phong_size %.3g\n" % (material.pov.specular_hardness / 3.14))
 250
 251                 # POV-Ray 'specular' keyword corresponds to a Blinn model, without the ior.
 252                 elif material.pov.specular_shader == "BLINN":
 253                     # Use blender Blinn's IOR just as some factor for spec intensity
 254                     tab_write(
 255                         file,
 256                         "specular %.3g\n"
 257                         % (material.pov.specular_intensity * (material.pov.specular_ior / 4.0)),
 258                     )
 259                     tab_write(file, "roughness %.3g\n" % roughness)
 260                     # Could use brilliance 2(or varying around 2 depending on ior or factor) too.
 261
 262                 elif material.pov.specular_shader == "TOON":
 263                     tab_write(file, "phong %.3g\n" % (material.pov.specular_intensity * 2.0))
 264                     # use extreme phong_size
 265                     tab_write(
 266                         file, "phong_size %.3g\n" % (0.1 + material.pov.specular_toon_smooth / 2.0)
 267                     )
 268
 269                 elif material.pov.specular_shader == "WARDISO":
 270                     # find best suited default constant for brilliance Use both phong and
 271                     # specular for some values.
 272                     tab_write(
 273                         file,
 274                         "specular %.3g\n"
 275                         % (
 276                             material.pov.specular_intensity / (material.pov.specular_slope + 0.0005)
 277                         ),
 278                     )
 279                     # find best suited default constant for brilliance Use both phong and
 280                     # specular for some values.
 281                     tab_write(
 282                         file, "roughness %.4g\n" % (0.0005 + material.pov.specular_slope / 10.0)
 283                     )
 284                     # find best suited default constant for brilliance Use both phong and
 285                     # specular for some values.
 286                     tab_write(file, "brilliance %.4g\n" % (1.8 - material.pov.specular_slope * 1.8))
 287             elif ref_level_bound == 3:
 288                 # Spec must be Max at ref_level_bound 3 so that white of mixing texture always shows specularity
 289                 # That's why it's multiplied by 255. maybe replace by texture's brightest pixel value?
 290                 if material.pov_texture_slots:
 291                     max_spec_factor = (
 292                         material.pov.specular_intensity
 293                         * material.pov.specular_color.v
 294                         * 255
 295                         * slot.specular_factor
 296                     )
 297                 else:
 298                     max_spec_factor = (
 299                         material.pov.specular_intensity * material.pov.specular_color.v * 255
 300                     )
 301                 tab_write(file, "specular %.3g\n" % max_spec_factor)
 302                 tab_write(file, "roughness %.3g\n" % (1 / material.pov.specular_hardness))
 303             tab_write(file, "diffuse %.3g, %.3g\n" % (front_diffuse, back_diffuse))
 304
 305             tab_write(file, "ambient %.3g\n" % material.pov.ambient)
 306             # POV-Ray blends the global value
 307             # tab_write(file, "ambient rgb <%.3g, %.3g, %.3g>\n" % \
 308             #         tuple([c*material.pov.ambient for c in world.ambient_color]))
 309             tab_write(file, "emission %.3g\n" % material.pov.emit)  # New in POV-Ray 3.7
 310
 311             # POV-Ray just ignores roughness if there's no specular keyword
 312             # tab_write(file, "roughness %.3g\n" % roughness)
 313
 314             if material.pov.conserve_energy:
 315                 # added for more realistic shading. Needs some checking to see if it
 316                 # really works. --Maurice.
 317                 tab_write(file, "conserve_energy\n")
 318
 319             if colored_specular_found:
 320                 tab_write(file, "metallic\n")
 321
 322             # 'phong 70.0 '
 323             if ref_level_bound != 1 and material.pov_raytrace_mirror.use:
 324                 raytrace_mirror = material.pov_raytrace_mirror
 325                 if raytrace_mirror.reflect_factor:
 326                     tab_write(file, "reflection {\n")
 327                     tab_write(file, "rgb <%.3g, %.3g, %.3g>\n" % material.pov.mirror_color[:])
 328                     if material.metallic:
 329                         tab_write(file, "metallic %.3g\n" % material.metallic)
 330                     # Blurry reflections for UberPOV
 331                     if using_uberpov and raytrace_mirror.gloss_factor < 1.0:
 332                         # tab_write(file, "#ifdef(unofficial) #if(unofficial = \"patch\") #if(patch(\"upov-reflection-roughness\") > 0)\n")
 333                         tab_write(
 334                             file, "roughness %.6f\n" % (0.000001 / raytrace_mirror.gloss_factor)
 335                         )
 336                         # tab_write(file, "#end #end #end\n") # This and previous comment for backward compatibility, messier pov code
 337                     if material.pov.mirror_use_IOR:  # WORKING ?
 338                         # Removed from the line below: gives a more physically correct
 339                         # material but needs proper IOR. --Maurice
 340                         tab_write(file, "fresnel 1 ")
 341                     tab_write(
 342                         file,
 343                         "falloff %.3g exponent %.3g} "
 344                         % (raytrace_mirror.fresnel, raytrace_mirror.fresnel_factor),
 345                     )
 346
 347             if material.pov_subsurface_scattering.use:
 348                 subsurface_scattering = material.pov_subsurface_scattering
 349                 tab_write(
 350                     file,
 351                     "subsurface { translucency <%.3g, %.3g, %.3g> }\n"
 352                     % (
 353                         (subsurface_scattering.radius[0]),
 354                         (subsurface_scattering.radius[1]),
 355                         (subsurface_scattering.radius[2]),
 356                     ),
 357                 )
 358
 359             if material.pov.irid_enable:
 360                 tab_write(
 361                     file,
 362                     "irid { %.4g thickness %.4g turbulence %.4g }"
 363                     % (
 364                         material.pov.irid_amount,
 365                         material.pov.irid_thickness,
 366                         material.pov.irid_turbulence,
 367                     ),
 368                 )
 369
 370         else:
 371             tab_write(file, "diffuse 0.8\n")
 372             tab_write(file, "phong 70.0\n")
 373
 374             # tab_write(file, "specular 0.2\n")
 375
 376         # This is written into the object
 377         """
 378         if material and material.pov.transparency_method=='RAYTRACE':
 379             'interior { ior %.3g} ' % material.raytrace_transparency.ior
 380         """
 381
 382         # tab_write(file, "crand 1.0\n") # Sand granyness
 383         # tab_write(file, "metallic %.6f\n" % material.metallic)
 384         # tab_write(file, "phong %.6f\n" % material.spec)
 385         # tab_write(file, "phong_size %.6f\n" % material.spec)
 386         # tab_write(file, "brilliance %.6f " % (material.pov.specular_hardness/256.0) # Like hardness
 387
 388         tab_write(file, "}\n\n")
 389
 390     # ref_level_bound=2 Means translation of spec and mir levels for when no map influences them
 391     pov_has_no_specular_maps(file, ref_level_bound=2)
 392
 393     if material:
 394         special_texture_found = False
 395         tmpidx = -1
 396         slot = None
 397         for t in material.pov_texture_slots:
 398             tmpidx += 1
 399             # index = material.pov.active_texture_index
 400             slot = material.pov_texture_slots[tmpidx]  # [index]
 401             povtex = slot.texture  # slot.name
 402             tex = bpy.data.textures[povtex]
 403
 404             if t and t.use and tex is not None:
 405
 406                 if (tex.type == "IMAGE" and tex.image) or tex.type != "IMAGE":
 407                     # validPath
 408                     if (
 409                         t
 410                         and t.use
 411                         and (
 412                             t.use_map_specular
 413                             or t.use_map_raymir
 414                             or t.use_map_normal
 415                             or t.use_map_alpha
 416                         )
 417                     ):
 418                         special_texture_found = True
 419
 420                         continue  # Some texture found
 421
 422         if special_texture_found or colored_specular_found:
 423             # ref_level_bound=1 Means No specular nor Mirror reflection
 424             pov_has_no_specular_maps(file, ref_level_bound=1)
 425
 426             # ref_level_bound=3 Means Maximum Spec and Mirror
 427             pov_has_no_specular_maps(file, ref_level_bound=3)