Formatting and fixes

* Moved: some existing functions into new separate files to improve code
readability (detailed in __init__.py docstring)

* Remove: max_intersections deprecated in pov 3.8

* Add: Validate utf-8 characters with specific API function at session's
first script init

* Add : Icons to some text fields and inviting labels

* Change default camera normal perturbation value to non zero since its
use is first driven by a boolean toggle

* Change: lists (vectors and indices) are now exported in one line by
default for better manual scene overview and debugging

* Change: a couple of tooltips corrections

* Change : renamed many variables and functions to snake_case according
to recommanded style guides

* Fix : Heightfield primitive (forward slashes were expected for
displacement texture path)

* Fix : Text nippet insertion operator

* Fix : added console print tip to check executable path on failure to
process

* Fix : tweaked finished render say command for Linux

* Fix : interface of some shader nodes broken since 2.8 api changes

* Fix : export hair particles

1 files changed, 268 insertions, 0 deletions

diff --git a/render_povray/scripting_gui.py b/render_povray/scripting_gui.py
new file mode 100755
index 00000000..99006af1
--- /dev/null
+++ b/render_povray/scripting_gui.py
@@ -0,0 +1,268 @@
+# ##### 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>
+"""User interface to POV Scene Description Language snippets or full includes:
+
+import, load, create or edit """
+
+import bpy
+from bpy.utils import register_class, unregister_class
+from bpy.types import Operator, Menu, Panel
+from sys import platform  # really import here, as in ui.py and in render.py?
+import os  # really import here and in render.py?
+from os.path import isfile
+
+
+def locate_docpath():
+    """POV can be installed with some include files.
+
+    Get their path as defined in user preferences or registry keys for
+    the user to be able to invoke them."""
+
+    addon_prefs = bpy.context.preferences.addons[__package__].preferences
+    # Use the system preference if its set.
+    pov_documents = addon_prefs.docpath_povray
+    if pov_documents:
+        if os.path.exists(pov_documents):
+            return pov_documents
+        # Implicit else, as here return was still not triggered:
+        print(
+            "User Preferences path to povray documents %r NOT FOUND, checking $PATH" % pov_documents
+        )
+
+    # Windows Only
+    if platform.startswith('win'):
+        import winreg
+
+        try:
+            win_reg_key = winreg.OpenKey(
+                winreg.HKEY_CURRENT_USER, "Software\\POV-Ray\\v3.7\\Windows"
+            )
+            win_docpath = winreg.QueryValueEx(win_reg_key, "DocPath")[0]
+            pov_documents = os.path.join(win_docpath, "Insert Menu")
+            if os.path.exists(pov_documents):
+                return pov_documents
+        except FileNotFoundError:
+            return ""
+    # search the path all os's
+    pov_documents_default = "include"
+
+    os_path_ls = os.getenv("PATH").split(':') + [""]
+
+    for dir_name in os_path_ls:
+        pov_documents = os.path.join(dir_name, pov_documents_default)
+        if os.path.exists(pov_documents):
+            return pov_documents
+    return ""
+
+
+################################################################################
+class TextButtonsPanel:
+    """Use this class to define buttons from the side tab of
+    text window."""
+
+    bl_space_type = 'TEXT_EDITOR'
+    bl_region_type = 'UI'
+    bl_label = "POV-Ray"
+    COMPAT_ENGINES = {'POVRAY_RENDER'}
+
+    @classmethod
+    def poll(cls, context):
+        text = context.space_data
+        rd = context.scene.render
+        return text and (rd.engine in cls.COMPAT_ENGINES)
+
+
+###############################################################################
+# Text Povray Settings
+###############################################################################
+
+
+class TEXT_OT_POV_insert(Operator):
+    """Use this class to create blender text editor operator to insert pov snippets like other pov IDEs"""
+
+    bl_idname = "text.povray_insert"
+    bl_label = "Insert"
+
+    filepath: bpy.props.StringProperty(name="Filepath", subtype='FILE_PATH')
+
+    @classmethod
+    def poll(cls, context):
+        text = context.space_data.text
+        return context.area.type == 'TEXT_EDITOR' and text is not None
+        # return bpy.ops.text.insert.poll() this Bpy op has no poll()
+
+    def execute(self, context):
+        if self.filepath and isfile(self.filepath):
+            file = open(self.filepath, "r")
+            bpy.ops.text.insert(text=file.read())
+
+            # places the cursor at the end without scrolling -.-
+            # context.space_data.text.write(file.read())
+            file.close()
+        return {'FINISHED'}
+
+
+def validinsert(ext):
+    """Since preview images could be in same folder, filter only insertable text"""
+    return ext in {".txt", ".inc", ".pov"}
+
+
+class TEXT_MT_POV_insert(Menu):
+    """Use this class to create a menu launcher in text editor for the TEXT_OT_POV_insert operator ."""
+
+    bl_label = "Insert"
+    bl_idname = "TEXT_MT_POV_insert"
+
+    def draw(self, context):
+        pov_documents = locate_docpath()
+        prop = self.layout.operator("wm.path_open", text="Open folder", icon='FILE_FOLDER')
+        prop.filepath = pov_documents
+        self.layout.separator()
+
+        pov_insert_items_list = []
+        for root, dirs, files in os.walk(pov_documents):  # todo: structure submenus by dir
+            pov_insert_items_list.append(root)
+        print(pov_insert_items_list)
+        self.path_menu(
+            pov_insert_items_list,
+            "text.povray_insert",
+            # {"internal": True},
+            filter_ext=validinsert,
+        )
+
+
+class TEXT_PT_POV_custom_code(TextButtonsPanel, Panel):
+    """Use this class to create a panel in text editor for the user to decide if he renders text
+
+    only or adds to 3d scene."""
+
+    bl_label = "POV"
+    COMPAT_ENGINES = {'POVRAY_RENDER'}
+
+    def draw(self, context):
+        layout = self.layout
+
+        text = context.space_data.text
+
+        pov_documents = locate_docpath()
+        if not pov_documents:
+            layout.label(text="Please configure ", icon="INFO")
+            layout.label(text="default pov include path ")
+            layout.label(text="in addon preferences")
+            # layout.separator()
+            layout.operator(
+                "preferences.addon_show",
+                text="Go to Render: Persistence of Vision addon",
+                icon="PREFERENCES",
+            ).module = "render_povray"
+
+            # layout.separator()
+        else:
+            # print(pov_documents)
+            layout.menu(TEXT_MT_POV_insert.bl_idname)
+
+        if text:
+            box = layout.box()
+            box.label(text='Source to render:', icon='RENDER_STILL')
+            row = box.row()
+            row.prop(text.pov, "custom_code", expand=True)
+            if text.pov.custom_code in {'3dview'}:
+                box.operator("render.render", icon='OUTLINER_DATA_ARMATURE')
+            if text.pov.custom_code in {'text'}:
+                rtext = bpy.context.space_data.text  # is r a typo ? or why written, not used
+                box.operator("text.run", icon='ARMATURE_DATA')
+            # layout.prop(text.pov, "custom_code")
+            elif text.pov.custom_code in {'both'}:
+                box.operator("render.render", icon='POSE_HLT')
+                layout.label(text="Please specify declared", icon="INFO")
+                layout.label(text="items in properties ")
+                # layout.label(text="")
+                layout.label(text="replacement fields")
+
+
+###############################################
+# Text editor templates from header menu
+
+
+class TEXT_MT_POV_templates(Menu):
+    """Use this class to create a menu for the same pov templates scenes as other pov IDEs."""
+
+    bl_label = "POV"
+
+    # We list templates on file evaluation, we can assume they are static data,
+    # and better avoid running this on every draw call.
+    template_paths = [os.path.join(os.path.dirname(__file__), "templates_pov")]
+
+    def draw(self, context):
+        self.path_menu(self.template_paths, "text.open", props_default={"internal": True})
+
+
+def menu_func_templates(self, context):
+    """Add POV files to the text editor templates menu"""
+    # Do not depend on POV being active renderer here...
+    self.layout.menu("TEXT_MT_POV_templates")
+
+
+###############################################
+# POV Import menu
+class VIEW_MT_POV_import(Menu):
+    """Use this class for the import menu."""
+
+    bl_idname = "POVRAY_MT_import_tools"
+    bl_label = "Import"
+
+    def draw(self, context):
+        layout = self.layout
+        layout.operator_context = 'INVOKE_REGION_WIN'
+        layout.operator("import_scene.pov", icon="FORCE_LENNARDJONES")
+
+
+def menu_func_import(self, context):
+    """Add the import operator to menu"""
+    engine = context.scene.render.engine
+    if engine == 'POVRAY_RENDER':
+        self.layout.operator("import_scene.pov", icon="FORCE_LENNARDJONES")
+
+
+classes = (
+    VIEW_MT_POV_import,
+    TEXT_OT_POV_insert,
+    TEXT_MT_POV_insert,
+    TEXT_PT_POV_custom_code,
+    TEXT_MT_POV_templates,
+)
+
+
+def register():
+
+    for cls in classes:
+        register_class(cls)
+
+    bpy.types.TOPBAR_MT_file_import.append(menu_func_import)
+    bpy.types.TEXT_MT_templates.append(menu_func_templates)
+
+
+def unregister():
+
+    bpy.types.TEXT_MT_templates.remove(menu_func_templates)
+    bpy.types.TOPBAR_MT_file_import.remove(menu_func_import)
+
+    for cls in reversed(classes):
+        unregister_class(cls)