EnlivenMinetest/utilities/blender/generate_lua_collisionbox.py

#!/usr/bin/env python
"""
collisionbox Lua generator
1. Select a mob mesh or an Empty
2. Press the "Run Script" button below
   - The script copies the collisionbox the the clipboard.
   - An 'Empty' with the object's name will appear,
     which visually represents the collisionbox
     (which MUST be symmetrical on horizontal axes and
     centered at 0,0,0 for Minetest, since
     collision boxes to not turn).
3. To adjust, scale the Empty.collisionbox.* object
   in Blender then repeat steps 1-2. To keep the Empty
   symmetrical for Minetest, scale ONLY with one
   of the following hotkey sequences (with
   the mouse pointer in the 3D View):
   - 's'
   - 's', 'z'
   - 's', "shift z"

How to use: Paste this script into a Blender"
Text Editor panel, select an object,"
press the 'Run Script' button")
"""
print("""

STARTING generate_lua_collisionbox...
""")
y_up = True
enable_minetest = True
enable_lowest_h = False
enable_center_h = False
if enable_minetest:
    enable_lowest_h = True
    enable_center_h = True

hs = (0, 1)  # horizontal axis indices
v = 2  # vertical axis index
# Do NOT swap until end.
#if y_up:
#    hs = (0, 2)
#    v = 1
try:
    import bpy
except ImportError:
    print(__doc__)
    exit(1)
# from mathutils import Matrix
from mathutils import Vector
# from mathutils import Euler

def calculate_one():
    ob1 = None
    ob1 = bpy.context.active_object  # works with 2.7 or 2.8
    calculate_collisionbox(ob1)


class MessageBox(bpy.types.Operator):
    bl_idname = "message.messagebox"
    bl_label = ""
    message = bpy.props.StringProperty(
        name = "message",
        description = "message",
        default = ''
    )

    def execute(self, context):
        self.report({'INFO'}, self.message)
        # print(self.message)
        return {'FINISHED'}

    def invoke(self, context, event):
        return context.window_manager.invoke_props_dialog(self,
                                                          width=400)

    def draw(self, context):
        self.layout.label(text=self.message)
        self.layout.label(text="")
        # col = self.layout.column(align = True)
        # col.prop(context.scene, "my_string_prop")

bpy.utils.register_class(MessageBox)

msgSuffix = ""

def calculate_collisionbox(ob1):
    global msgSuffix
    mesh = None
    if ob1 is None:
        if len(bpy.context.selected_objects) > 0:
            ob1 = bpy.context.selected_objects[0]
    if ob1 is not None:
        mesh = ob1.data
    if ob1 is None:
        msg = "Nothing is selected."
        bpy.ops.message.messagebox('INVOKE_DEFAULT', message = msg)
    elif (mesh is not None) and (not hasattr(mesh, 'vertices')):
        msg = ("A collision box cannot be calculated for a non-mesh"
               " object.")
        bpy.ops.message.messagebox('INVOKE_DEFAULT', message = msg)
    else:
        # extents1 = ob1.dimensions.copy()
        obj1Loc = ob1.location

        # See https://blender.stackexchange.com/questions/8459/get-blender-x-y-z-and-bounding-box-with-script
        # bbox_corners = [ob1.matrix_world * Vector(corner) for corner in ob1.bound_box]


        # See https://blender.stackexchange.com/questions/6139/how-to-iterate-through-all-vertices-of-an-object-that-contains-multiple-meshes
        # print("mesh:" + str(mesh))
        # print("hasattr(mesh, 'vertices'):"
              # + str(hasattr(mesh, 'vertices')))]
        mins = [None, None, None]  # minimums; in outer scope for checks.
        maxes = [None, None, None]  # minimums; in outer scope for checks.
        if mesh is not None:
            wm = ob1.matrix_world
            for vert in mesh.vertices:
                # This matrix multiplication is NOT transitive.
                try:
                    loc = wm @ vert.co
                except TypeError:
                    loc = wm * vert.co  # Blender <2.8
                # NOTE: swap y and z for Minetest (y-up) LATER
                coords = (loc.x, loc.y, loc.z)
                for i in range(3):
                    if (mins[i] is None) or (coords[i] < mins[i]):
                        mins[i] = coords[i]
                    if (maxes[i] is None) or (coords[i] > maxes[i]):
                        maxes[i] = coords[i]
            # print(str(extents1))
            # print("--by vertices (raw):")
            # print("    collisionbox = {{{:.2f}, {:.2f}, {:.2f}, {:.2f},"
                  # " {:.2f}, {:.2f}}}".format(mins[0], mins[2], mins[1],
                                             # maxes[0], maxes[2], maxes[1]))

            # Use ob1.matrix_world (above) instead of incrementing
            # ob1.location.x, y, and z

            # newNamePrefix = "Empty.EDGE." + ob1.name
            # i = 0
            # wm = ob1.matrix_world
            # for vert in mesh.vertices:
                # newName = newNamePrefix + "." + str(i)
                # # This matrix multiplication is NOT transitive.
                # try:
                    # loc = wm @ vert.co
                # except TypeError:
                    # loc = wm * vert.co  # Blender <2.8
                # isFar = False
                # if loc.x == maxes[0] or loc.y == maxes[1] or loc.z == maxes[2]:
                    # isFar = True
                # elif loc.x == mins[0] or loc.y == mins[1] or loc.z == mins[2]:
                    # isFar = True
                # if isFar:
                    # pass
                    # # result = bpy.ops.object.add(type='EMPTY', radius=.25,
                                                # # location=loc)
                    # # NOTE: result is merely {'FINISHED'}
                    # # print("{:.2f}, {:.2f}, {:.2f}".format(loc.x, loc.y,
                                                          # # loc.z))

                    # bpy.ops.object.add_named(name=newName, type='EMPTY',
                                             # radius=.25, location=loc)
                # i += 1
        else:
            extents1 = ob1.scale.copy()
            print(dir(ob1))
            # Object is an empty, so scale up for Minetest
            try:
                extents1.x = extents1.x * (ob1.empty_display_size * 2.0)
                extents1.y = extents1.y * (ob1.empty_display_size * 2.0)
                extents1.z = extents1.z * (ob1.empty_display_size * 2.0)
            except AttributeError:
                # Blender 2.7
                extents1.x = extents1.x * (ob1.empty_draw_size * 2.0)
                extents1.y = extents1.y * (ob1.empty_draw_size * 2.0)
                extents1.z = extents1.z * (ob1.empty_draw_size * 2.0)
            mins[0] = obj1Loc.x - extents1.x / 2.0
            maxes[0] = obj1Loc.x + extents1.x / 2.0
            mins[1] = obj1Loc.y - extents1.y / 2.0
            maxes[1] = obj1Loc.y + extents1.y / 2.0
            mins[2] = obj1Loc.z - extents1.z / 2.0
            maxes[2] = obj1Loc.z + extents1.z / 2.0
            msgSuffix = " (using Empty object's scale)"
            # print("--using empty object:")

        # use ground as bottom (don't do this--it is not the Minetest way)
        # if mins[2] < 0.0:
        #     maxes[1] -= mins[1]
        #     mins[1] = 0.0

        # print("    collisionbox = {{{:.2f}, {:.2f}, {:.2f}, {:.2f}, {:.2f},"
              # " {:.2f}}}".format(mins[0], mins[1], mins[2], maxes[0], maxes[1], maxes[2]))
        sizes = [None, None, None]
        centers = [None, None, None]
        for i in range(3):
            sizes[i] = maxes[i] - mins[i]
            centers[i] = mins[i] + sizes[i] / 2.0

        if enable_lowest_h:
            # OK to use z as up, since will y&z will be swapped if y_up
            hSize = None
            for i in range(len(hs)):
                axis_i = hs[i]
                if (hSize is None) or (sizes[axis_i] < hSize):
                    hSize = sizes[axis_i]
            for i in range(len(hs)):
                axis_i = hs[i]
                sizes[axis_i] = hSize
                mins[axis_i] = centers[axis_i] - hSize / 2
                maxes[axis_i] = mins[axis_i] + hSize

        if enable_center_h:
            for i in range(len(hs)):
                axis_i = hs[i]
                centers[i] = 0
                mins[axis_i] = centers[axis_i] - sizes[axis_i] / 2
                maxes[axis_i] = mins[axis_i] + sizes[axis_i]

        loc = (centers[0], centers[1], centers[2])
        bpy.ops.object.add(type='EMPTY', radius=.5, location=loc)
        collisionboxName = "Empty.collisionbox." + ob1.name
        newEmpty = bpy.context.object  # works with 2.7 or 2.8
        # newEmpty = bpy.context.selected_objects[0]
        try:
            pass
            # bpy.context.scene.collection.objects.link(newEmpty)
        except AttributeError:
            # Blender 2.7
            pass
        newEmpty.name = collisionboxName
        newEmpty.location = (centers[0], centers[1], centers[2])
        try:
            newEmpty.empty_display_type = 'CUBE'
            # newEmpty.empty_display_size = (sizes[0], sizes[1], sizes[2])
        except AttributeError:
            # Blender 2.7:
            newEmpty.empty_draw_type = 'CUBE'
            # newEmpty.empty_draw_size = (sizes[0], sizes[1], sizes[2])
        # newEmpty.dimensions = (sizes[0], sizes[1], sizes[2])
        # newEmpty.scale = (sizes[0]/2.0, sizes[1]/2.0, sizes[2]/2.0)
        newEmpty.scale = (sizes[0], sizes[1], sizes[2])

        if enable_minetest:
            for i in range(3):
                mins[i] /= 10.0
                maxes[i] /= 10.0

        msg = ('Size is not available. Make sure you have a mesh object'
               ' selected.')

        if mins[0] is not None:
            # swap y and z for Minetest (y-up):
            if y_up:
                tmp = mins[1]
                mins[1] = mins[2]
                mins[2] = tmp
                tmp = maxes[1]
                maxes[1] = maxes[2]
                maxes[2] = tmp
            msg = ("    collisionbox = {{{:.2f}, {:.2f}, {:.2f}, {:.2f},"
                   " {:.2f}, {:.2f}}}".format(mins[0], mins[1], mins[2],
                                              maxes[0], maxes[1], maxes[2]))
            if len(msgSuffix) > 0:
                msgSuffix = "  -- " + msgSuffix
            bpy.context.window_manager.clipboard = msg + msgSuffix
            msg += " --copied to clipboard"
            # if enable_minetest:
                # msg += "  -- *10"
        print(msg)

        bpy.ops.message.messagebox('INVOKE_DEFAULT', message=msg)

# Unregistering before user clicks the MessageBox will crash Blender!
# bpy.utils.unregister_class(MessageBox)

calculate_one()