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# This file is a part of the HiRISE DTM Importer for Blender
#
# Copyright (C) 2017 Arizona Board of Regents on behalf of the Planetary Image
# Research Laboratory, Lunar and Planetary Laboratory at the University of
# Arizona.
#
# 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 3 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, see <http://www.gnu.org/licenses/>.
"""Blender menu importer for loading a DTM"""
import bpy
import bpy.props
from bpy_extras.io_utils import ImportHelper
from ..mesh.terrain import BTerrain
from ..mesh.dtm import DTM
class ImportHiRISETerrain(bpy.types.Operator, ImportHelper):
"""DTM Import Helper"""
bl_idname = "import.pds_dtm"
bl_label = "Import HiRISE Terrain Model"
bl_options = {'UNDO'}
filename_ext = ".img"
filter_glob = bpy.props.StringProperty(
options={'HIDDEN'},
default="*.img"
)
# Allow the user to specify a resolution factor for loading the
# terrain data at. This is useful because it allows the user to stage
# a scene with a low resolution terrain map, apply textures, modifiers,
# etc. and then increase the resolution to prepare for final rendering.
#
# Displaying this value as a percentage (0, 100] is an intuitive way
# for users to grasp what this value does. The DTM importer, however,
# wants to recieve a value between (0, 1]. This is obviously a
# straightforward conversion:
#
# f(x) = x / 100
#
# But this conversion should happen here, in the terrain panel, rather
# than in the DTM importing utility itself. We can't pass get/set
# functions to the property itself because they result in a recursion
# error. Instead, we use another, hidden, property to store the scaled
# resolution.
dtm_resolution = bpy.props.FloatProperty(
subtype="PERCENTAGE",
description=(
"Percentage scale for terrain model resolution. 100\% loads the "
"model at full resolution (i.e. one vertex for each post in the "
"original terrain model) and is *MEMORY INTENSIVE*. Downsampling "
"uses Nearest Neighbors. You will be able to increase the "
"resolution of your mesh later, and still maintain all textures, "
"transformations, modifiers, etc., so best practice is to start "
"small. The downsampling algorithm may need to alter the "
"resolution you specify here to ensure it results in a whole "
"number of vertices. If it needs to alter the value you specify, "
"you are guaranteed that it will shrink it (i.e. decrease the "
"DTM resolution"
),
name="Terrain Model Resolution",
min=1.0, max=100.0, default=10.0
)
scaled_dtm_resolution = bpy.props.FloatProperty(
options={'HIDDEN'},
name="Scaled Terrain Model Resolution",
get=(lambda self: self.dtm_resolution / 100)
)
# HiRISE DTMs are huge, but it can be nice to load them in at scale. Here,
# we present the user with the option of setting up the Blender viewport
# to avoid a couple of common pitfalls encountered when working with such
# a large mesh.
#
# 1. The Blender viewport has a default clipping distance of 1km. HiRISE
# DTMs are often many kilometers in each direction. If this setting is
# not changed, an unsuspecting user may only see part (or even nothing
# at all) of the terrain. This option (true, by default) instructs
# Blender to change the clipping distance to something appropriate for
# the DTM, and scales the grid floor to have gridlines 1km apart,
# instead of 1m apart.
should_setup_viewport = bpy.props.BoolProperty(
description=(
"Set up the Blender screen to try and avoid clipping the DTM "
"and to make the grid floor larger. *WARNING* This will change "
"clipping distances and the Blender grid floor, and will fit the "
"DTM in the viewport"
),
name="Setup Blender Scene", default=True
)
# 2. Blender's default units are dimensionless. This option instructs
# Blender to change its unit's dimension to meters.
should_setup_units = bpy.props.BoolProperty(
description=(
"Set the Blender scene to use meters as its unit"
),
name="Set Blender Units to Meters", default=True
)
def execute(self, context):
"""Runs when the "Import HiRISE Terrain Model" button is pressed"""
filepath = bpy.path.ensure_ext(self.filepath, self.filename_ext)
# Create a BTerrain from the DTM
dtm = DTM(filepath, self.scaled_dtm_resolution)
BTerrain.new(dtm)
# Set up the Blender UI
if self.should_setup_units:
self._setup_units(context)
if self.should_setup_viewport:
self._setup_viewport(context)
return {"FINISHED"}
def _setup_units(self, context):
"""Sets up the Blender scene for viewing the DTM"""
scene = bpy.context.scene
# Set correct units
scene.unit_settings.system = 'METRIC'
scene.unit_settings.scale_length = 1.0
return {'FINISHED'}
def _setup_viewport(self, context):
"""Sets up the Blender screen to make viewing the DTM easier"""
screen = bpy.context.screen
# Fetch the 3D_VIEW Area
for area in screen.areas:
if area.type == 'VIEW_3D':
space = area.spaces[0]
# Adjust 3D View Properties
# TODO: Can these be populated more intelligently?
space.clip_end = 100000
space.grid_scale = 1000
space.grid_lines = 50
# Fly to a nice view of the DTM
self._view_dtm(context)
return {'FINISHED'}
def _view_dtm(self, context):
"""Sets up the Blender screen to make viewing the DTM easier"""
screen = bpy.context.screen
# Fetch the 3D_VIEW Area
for area in screen.areas:
if area.type == 'VIEW_3D':
# Move the camera around in the viewport. This requires
# a context override.
for region in area.regions:
if region.type == 'WINDOW':
override = {
'area': area,
'region': region,
'edit_object': bpy.context.edit_object
}
# Center View on DTM (SHORTCUT: '.')
bpy.ops.view3d.view_selected(override)
# Move to 'TOP' viewport (SHORTCUT: NUMPAD7)
bpy.ops.view3d.viewnumpad(override, type='TOP')
return {'FINISHED'}
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