"""Grouper: the hull's three LODs side by side (critique round 1, M2), from the exported FBX files, Workbench with wireframe:
    blender.exe -b --factory-startup --python build/gr_lods_preview.py   -> previews/lods_hull.png (nothing saved)"""
import bpy, os, math
from mathutils import Vector

HERE = os.path.dirname(os.path.abspath(__file__))
ROOT = os.path.dirname(HERE)
for o in list(bpy.data.objects):
    bpy.data.objects.remove(o)
sc = bpy.context.scene
objs = []
for k, name in enumerate(("SM_Grouper_Hull", "SM_Grouper_Hull_LOD1", "SM_Grouper_Hull_LOD2")):
    before = set(bpy.data.objects)
    bpy.ops.import_scene.fbx(filepath=os.path.join(ROOT, "fbx", name + ".fbx"))
    new = [o for o in bpy.data.objects if o not in before and o.type == 'MESH' and not o.name.startswith("UCX_")]
    for o in bpy.data.objects:
        if o not in before and o.name.startswith("UCX_"):
            o.hide_render = True
    for o in new:
        o.rotation_euler = (0.0, 0.0, math.radians(-28))
        o.location.z += (1 - k) * 3.9
        o["tris"] = sum(len(p.vertices) - 2 for p in o.data.polygons)
        objs.append((name, o))
sc.render.engine = 'BLENDER_WORKBENCH'
sh = sc.display.shading
sh.light = 'STUDIO'; sh.color_type = 'SINGLE'; sh.single_color = (0.62, 0.64, 0.67); sh.show_cavity = False
sc.render.resolution_x, sc.render.resolution_y = 1400, 1900
wm = bpy.data.materials.new("_wire"); wm.diffuse_color = (0.02, 0.02, 0.03, 1)
for nm, o in objs:
    m = o.modifiers.new("w", 'WIREFRAME'); m.thickness = 0.004; m.use_replace = False; m.material_offset = len(o.data.materials)
    o.data.materials.append(wm)
sh.color_type = 'MATERIAL'
for m in bpy.data.materials:
    if m.name != "_wire":
        m.diffuse_color = (0.62, 0.64, 0.67, 1)
cam = bpy.data.objects.new("_c", bpy.data.cameras.new("_c")); sc.collection.objects.link(cam); sc.camera = cam
cam.data.type = 'ORTHO'; cam.data.ortho_scale = 12.4
cam.location = Vector((-20.0, 0.0, 0.0)); cam.rotation_euler = (math.radians(90), 0.0, math.radians(-90))
sc.render.filepath = os.path.join(ROOT, "previews", "lods_hull.png")
bpy.ops.render.render(write_still=True)
print("LODS", [(nm, o["tris"]) for nm, o in objs])