settled-reach/tooling/blender_create_clothing_refs.py

"""
blender_create_clothing_refs.py

Usage:
  tooling/blender --background --python tooling/blender_create_clothing_refs.py -- \\
    <bodies_dir> <clothing_output_dir>

Creates v0.2 placeholder reference clothing meshes for all 5 initial clothing items.
Meshes are authored on average_m by importing the relevant body segments, joining
them, and offsetting vertices outward along normals to simulate clothing thickness.

This produces placeholder-quality geometry only — not final art. The geometry reads
correctly at gameplay zoom and is sufficient to validate the Surface Deform pipeline
and compositor integration.

Arguments:
  bodies_dir           Directory with one subdir per body type (e.g. client/assets/characters/bodies/)
  clothing_output_dir  Root directory for clothing output (e.g. client/assets/characters/clothing/)

Output per item in <clothing_output_dir>/<item_id>/:
  reference.glb   -- placeholder clothing mesh on average_m geometry

Items produced:
  coveralls_basic   -- full-body work suit
  jacket_utility    -- upper body outerwear
  pants_cargo       -- lower body
  shirt_henley      -- upper body inner
  boots_work        -- foot slot

Decisions: D-162 (clothing pre-baked per body type via Surface Deform)
"""

import sys
import os
import bpy
import bmesh

REFERENCE_BODY = "average_m"

# Each item defines:
#   segments  -- body segment GLBs (from average_m) to import and join
#   thickness -- outward vertex offset in metres (clothing thickness simulation)
CLOTHING_ITEMS = {
    "coveralls_basic": {
        "description": "Full-body work suit",
        "segments": [
            "seg_torso", "seg_torso_upper",
            "seg_arm_upper_l", "seg_arm_upper_r",
            "seg_arm_lower_l", "seg_arm_lower_r",
            "seg_hand_l", "seg_hand_r",
            "seg_leg_upper_l", "seg_leg_upper_r",
            "seg_leg_lower_l", "seg_leg_lower_r",
            "seg_foot_l", "seg_foot_r",
        ],
        "thickness": 0.006,
    },
    "jacket_utility": {
        "description": "Upper body outerwear",
        "segments": [
            "seg_torso", "seg_torso_upper",
            "seg_arm_upper_l", "seg_arm_upper_r",
            "seg_arm_lower_l", "seg_arm_lower_r",
        ],
        "thickness": 0.008,  # slightly thicker for outerwear
    },
    "pants_cargo": {
        "description": "Lower body cargo trousers",
        "segments": [
            "seg_leg_upper_l", "seg_leg_upper_r",
            "seg_leg_lower_l", "seg_leg_lower_r",
        ],
        "thickness": 0.006,
    },
    "shirt_henley": {
        "description": "Upper body inner shirt",
        "segments": [
            "seg_torso", "seg_torso_upper",
            "seg_arm_upper_l", "seg_arm_upper_r",
        ],
        "thickness": 0.004,  # thinner for inner layer
    },
    "boots_work": {
        "description": "Work boots (foot slot)",
        "segments": [
            "seg_foot_l", "seg_foot_r",
            "seg_leg_lower_l", "seg_leg_lower_r",  # boot shaft reaches up the lower leg
        ],
        "thickness": 0.010,  # thicker for boots
    },
}


def clear_scene():
    """Remove all objects and purge orphan data."""
    bpy.ops.object.select_all(action='SELECT')
    bpy.ops.object.delete()
    bpy.ops.outliner.orphans_purge(do_recursive=True)


def import_glb(path):
    """Import a GLB file. Returns newly added objects."""
    before = set(bpy.context.scene.objects)
    bpy.ops.import_scene.gltf(filepath=path)
    return [o for o in bpy.context.scene.objects if o not in before]


def offset_vertices_along_normals(obj, thickness):
    """
    Move each vertex outward along its computed normal by `thickness` metres.
    Operates directly on mesh data -- no operators, reliable in headless mode.
    """
    bm = bmesh.new()
    bm.from_mesh(obj.data)
    bm.verts.ensure_lookup_table()

    # Ensure normals are up to date
    bm.normal_update()

    for v in bm.verts:
        v.co += v.normal * thickness

    bm.to_mesh(obj.data)
    bm.free()
    obj.data.update()


def export_glb(obj, output_path, armature=None):
    """Export a mesh (and optionally its armature) as GLB with skinning data."""
    bpy.ops.object.select_all(action='DESELECT')
    obj.select_set(True)
    if armature:
        armature.select_set(True)
    bpy.context.view_layer.objects.active = obj

    bpy.ops.export_scene.gltf(
        filepath=output_path,
        use_selection=True,
        export_format='GLB',
        export_animations=False,
        export_yup=True,
        export_image_format='AUTO',
        export_texcoords=True,
        export_normals=True,
        export_skins=armature is not None,
        export_materials='EXPORT',
    )


def create_reference_mesh(item_id, config, bodies_dir, output_dir):
    """
    Create the reference.glb for one clothing item on average_m geometry.
    Preserves bone weights from body segments so clothing deforms with the skeleton.
    Returns True on success, False on error.
    """
    print(f"\n{'='*60}")
    print(f"  Item: {item_id} — {config['description']}")

    clear_scene()

    average_m_dir = os.path.join(bodies_dir, REFERENCE_BODY)
    imported_meshes = []
    imported_armatures = []
    missing_segments = []

    for seg_name in config["segments"]:
        seg_path = os.path.join(average_m_dir, f"{seg_name}.glb")
        if not os.path.isfile(seg_path):
            missing_segments.append(seg_name)
            continue
        objs = import_glb(seg_path)
        meshes = [o for o in objs if o.type == 'MESH']
        armatures = [o for o in objs if o.type == 'ARMATURE']
        imported_meshes.extend(meshes)
        imported_armatures.extend(armatures)

    if missing_segments:
        print(f"  NOTE: Missing segments (skipped): {', '.join(missing_segments)}")

    if not imported_meshes:
        print(f"  ERROR: No segment meshes could be imported for {item_id}")
        return False

    print(f"  Imported {len(imported_meshes)} segments, "
          f"{len(imported_armatures)} armatures "
          f"({len(missing_segments)} missing)")

    # Use the first armature as the canonical one — all segments share the same rig
    canonical_armature = imported_armatures[0] if imported_armatures else None

    # Re-parent all meshes to the canonical armature (preserving bone weights)
    if canonical_armature:
        for m in imported_meshes:
            # Clear any existing parent
            m.parent = None
            m.matrix_world = m.matrix_world  # preserve world transform
            # Set parent to canonical armature with Armature modifier
            m.parent = canonical_armature
            m.parent_type = 'OBJECT'
            # Ensure Armature modifier exists pointing to canonical armature
            has_armature_mod = False
            for mod in m.modifiers:
                if mod.type == 'ARMATURE':
                    mod.object = canonical_armature
                    has_armature_mod = True
            if not has_armature_mod:
                mod = m.modifiers.new(name="Armature", type='ARMATURE')
                mod.object = canonical_armature

        # Remove duplicate armatures (keep only canonical)
        for arm in imported_armatures[1:]:
            bpy.data.objects.remove(arm, do_unlink=True)

    # Join all segments into one mesh (vertex groups / bone weights are preserved by join)
    bpy.ops.object.select_all(action='DESELECT')
    for m in imported_meshes:
        if m.name in bpy.data.objects:
            m.select_set(True)
    bpy.context.view_layer.objects.active = imported_meshes[0]
    if len(imported_meshes) > 1:
        bpy.ops.object.join()

    clothing_obj = bpy.context.active_object
    clothing_obj.name = f"ref_{item_id}"

    vertex_count_before = len(clothing_obj.data.vertices)
    print(f"  Mesh vertices: {vertex_count_before}")
    print(f"  Vertex groups (bone weights): {len(clothing_obj.vertex_groups)}")

    # Offset vertices outward to simulate clothing thickness
    thickness = config["thickness"]
    offset_vertices_along_normals(clothing_obj, thickness)
    print(f"  Applied {thickness*1000:.1f}mm outward offset")

    # Export with armature so clothing is skinned
    os.makedirs(output_dir, exist_ok=True)
    output_path = os.path.join(output_dir, "reference.glb")
    export_glb(clothing_obj, output_path, armature=canonical_armature)
    print(f"  Exported: {output_path}")

    return True


# -------------------------------------------------------------------------
# Entry point
# -------------------------------------------------------------------------

if __name__ == "__main__":
    argv = sys.argv
    if "--" not in argv:
        print("Usage: tooling/blender --background --python "
              "tooling/blender_create_clothing_refs.py -- "
              "<bodies_dir> <clothing_output_dir>")
        sys.exit(1)

    args = argv[argv.index("--") + 1:]
    if len(args) < 2:
        print("ERROR: Provide <bodies_dir> and <clothing_output_dir>")
        sys.exit(1)

    bodies_dir         = args[0]
    clothing_output_dir = args[1]

    # Preflight: check average_m dir exists
    avg_m_dir = os.path.join(bodies_dir, REFERENCE_BODY)
    if not os.path.isdir(avg_m_dir):
        print(f"ERROR: Reference body directory not found: {avg_m_dir}")
        sys.exit(1)

    print("\nClothing Reference Mesh Creator (v0.2 placeholder)")
    print(f"  Bodies dir:  {bodies_dir}")
    print(f"  Output dir:  {clothing_output_dir}")
    print(f"  Reference:   {REFERENCE_BODY}")
    print(f"  Items:       {len(CLOTHING_ITEMS)}")

    results = {}
    for item_id, config in CLOTHING_ITEMS.items():
        item_output_dir = os.path.join(clothing_output_dir, item_id)
        success = create_reference_mesh(item_id, config, bodies_dir, item_output_dir)
        results[item_id] = success

    # Summary
    print(f"\n{'='*60}")
    print("=== Clothing reference creation complete ===")
    ok_items = [k for k, v in results.items() if v]
    fail_items = [k for k, v in results.items() if not v]
    for item_id in CLOTHING_ITEMS:
        status = "OK" if results[item_id] else "FAILED"
        print(f"  {item_id:20s}  {status}")
    print(f"\n  OK: {len(ok_items)}  FAILED: {len(fail_items)}")

    if fail_items:
        sys.exit(1)