o3de/Gems/WhiteBox/Editor/Scripts/Tetrahedron.py

"""
Copyright (c) Contributors to the Open 3D Engine Project.
For complete copyright and license terms please see the LICENSE at the root of this distribution.

SPDX-License-Identifier: Apache-2.0 OR MIT
"""

import WhiteBoxMath as whiteBoxMath
import WhiteBoxInit as init 

import argparse
import azlmbr.legacy.general as general
import azlmbr.bus as bus
import azlmbr.whitebox.api as api

# usage: pyRunFile path/to/file/tetrahedron.py <radius>


# mathematically, a tetrahedron built with spherical coordinates will not be centered vertically at origin
# we need to calculate how far off it is to vertically center it
def calculate_offset_for_tetrahedron(radius):
    h1 = whiteBoxMath.spherical_to_cartesian(0.0, 0.0, radius).z
    h2 = whiteBoxMath.spherical_to_cartesian(109.5, 90.0, radius).z
    offset = (h1 + h2) * -0.5

    return whiteBoxMath.spherical_to_cartesian(0.0, 0.0, offset)


def create_tetrahedron(whiteBoxMesh, radius=0.75):
    # get coordinates for all the vertices using the internal angles of a tetrahedron
    offset = calculate_offset_for_tetrahedron(radius)
    pos1 = whiteBoxMath.spherical_to_cartesian(0.0, 0.0, radius).Add(offset)
    pos2 = whiteBoxMath.spherical_to_cartesian(109.5, 90.0, radius).Add(offset)
    pos3 = whiteBoxMath.spherical_to_cartesian(109.5, 210.0, radius).Add(offset)
    pos4 = whiteBoxMath.spherical_to_cartesian(109.5, 330.0, radius).Add(offset)

    # create vertices from all the coordinates
    v1 = whiteBoxMesh.AddVertex(pos1)
    v2 = whiteBoxMesh.AddVertex(pos2)
    v3 = whiteBoxMesh.AddVertex(pos3)
    v4 = whiteBoxMesh.AddVertex(pos4)

    # add polygons for each set of vertices
    fvh1 = whiteBoxMesh.AddTriPolygon(v1, v2, v3)
    fvh2 = whiteBoxMesh.AddTriPolygon(v1, v3, v4)
    fvh3 = whiteBoxMesh.AddTriPolygon(v1, v4, v2)
    fvh4 = whiteBoxMesh.AddTriPolygon(v2, v4, v3)


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description='Creates a tetrahedron.')
    parser.add_argument('radius', nargs='?', default=0.75, type=float, help='radius of the tetrahedron')
    args = parser.parse_args()

    # initialize whiteBoxMesh
    whiteBoxEntity = init.create_white_box_entity("WhiteBox-Tetrahedron")
    whiteBoxMeshComponent = init.create_white_box_component(whiteBoxEntity)
    whiteBoxMesh = init.create_white_box_handle(whiteBoxMeshComponent)

    # clear whiteBoxMesh to make a tetrahedron from scratch
    whiteBoxMesh.Clear()

    create_tetrahedron(whiteBoxMesh, args.radius)

    # update whiteBoxMesh
    init.update_white_box(whiteBoxMesh, whiteBoxMeshComponent)