animation/characters/work/lena/34_apply_bust.py

# Stage 34: apply the chosen bust size and write the v04 master + GLB.
#
#   blender --background --python 34_apply_bust.py -- <in.blend> <out.blend> <out.glb> <k> [review]
#
# k comes from 33_bust_variants.py. k=0.50 was chosen: it puts bust projection at +0.0155 H
# against the approved concept turnaround's +0.0156 H, the only quantitative anchor available.
# Two caveats recorded so the number is not over-trusted later:
#   * the metric SATURATES below ~0.5 (k=0.35 measures +0.0154, indistinguishable), because as the
#     forms shrink the "deepest slice" row migrates and stops tracking breast volume;
#   * the reference reading may be inflated by the T-pose arm crossing the chest in a side view,
#     which would mean the true reference bust is smaller still — so 0.5 is a floor, not a midpoint.
# Front renders cannot tell these variants apart at all (the frontal key light flattens the chest);
# judge from the side. Re-running at another k is seconds now that the wall is cached.
import bpy, sys, os, math, time
import numpy as np
from mathutils import Vector

argv = sys.argv[sys.argv.index("--") + 1:]
BLEND, OUT_BLEND, OUT_GLB, K = argv[0], argv[1], argv[2], float(argv[3])
REVIEW = argv[4] if len(argv) > 4 else ""
t0 = time.time()

Z0, Z1 = 0.620, 0.790
Z_FADE = 0.022
X_MAX = 0.135
X_FADE = 0.022
Y_FRONT = 0.010
UNIT_MM = 1815.0


def log(m):
    print(f"[v04 {time.time()-t0:6.1f}s] {m}", flush=True)


def smoothstep(x):
    x = np.clip(x, 0.0, 1.0)
    return x * x * (3.0 - 2.0 * x)


bpy.ops.wm.open_mainfile(filepath=BLEND)
ob = max([o for o in bpy.data.objects if o.type == 'MESH'],
         key=lambda o: len(o.data.vertices))
me = ob.data
n_v = len(me.vertices)
orig_mats = [ms.material for ms in ob.material_slots]
co = np.empty(n_v * 3)
me.vertices.foreach_get("co", co)
co = co.reshape(-1, 3)
log(f"in: {n_v}v, mats={[m.name if m else None for m in orig_mats]}")

CACHE = os.path.join(os.path.dirname(os.path.abspath(BLEND)), "_bust_wall_cache.npy")
if not os.path.exists(CACHE):
    raise SystemExit(f"[v04] FATAL: wall cache missing ({CACHE}); run 33_bust_variants.py first")
wall = np.load(CACHE)
if wall.shape != co.shape:
    raise SystemExit(f"[v04] FATAL: cache shape {wall.shape} != mesh {co.shape} — "
                     f"the cache belongs to a different mesh")
log(f"wall cache loaded ({CACHE})")

W = (smoothstep((co[:, 2] - (Z0 - Z_FADE)) / Z_FADE)
     * smoothstep(((Z1 + Z_FADE) - co[:, 2]) / Z_FADE)
     * smoothstep(((X_MAX + X_FADE) - np.abs(co[:, 0])) / X_FADE)
     * smoothstep((Y_FRONT - co[:, 1]) / 0.030))
P = co + (W * (K - 1.0))[:, None] * (co - wall)
d = np.linalg.norm(P - co, axis=1) * UNIT_MM
log(f"k={K}: {int((d>0.05).sum())} verts moved >0.05 mm, max {d.max():.1f} mm, "
    f"median(region) {np.median(d[W>0.5]):.2f} mm")

me.vertices.foreach_set("co", P.reshape(-1))
me.update()
vn = np.empty(n_v * 3, dtype=np.float32)
me.vertices.foreach_get("normal", vn)
if me.has_custom_normals:
    me.normals_split_custom_set_from_vertices(vn.reshape(-1, 3))

# ---- verify: bust projection + that nothing outside the chest moved ----
def bust_projection(X):
    z0 = X[:, 2].min()
    Hh = X[:, 2].max() - z0
    u = (X[:, 2] - z0) / Hh
    NB = 220
    uu = np.linspace(0, 1, NB)
    fm = np.full(NB, np.nan)
    dm = np.full(NB, np.nan)
    for i, uc in enumerate(uu):
        sel = np.abs(u - uc) < (0.5 / NB) * 1.6
        if sel.sum() < 8:
            continue
        t = X[sel][np.abs(X[sel][:, 0]) < 0.16]
        if len(t) >= 8:
            fm[i] = t[:, 1].min() / Hh
            dm[i] = (t[:, 1].max() - t[:, 1].min()) / Hh
    b = (uu > 0.66) & (uu < 0.80) & np.isfinite(dm)
    ib = int(np.nanargmax(np.where(b, dm, -np.inf)))
    b2 = (uu > 0.60) & (uu < 0.70) & np.isfinite(dm)
    iu = int(np.nanargmin(np.where(b2, dm, np.inf)))
    return fm[iu] - fm[ib]


print(f"BUST PROJECTION  before {bust_projection(co):+.4f} H  ->  after "
      f"{bust_projection(P):+.4f} H   (reference +0.0156)")
outside = d[W <= 0.02]
print(f"OUTSIDE THE REGION: max move {outside.max() if len(outside) else 0:.4f} mm "
      f"(should be ~0)")
h0 = co[:, 2].max() - co[:, 2].min()
h1 = P[:, 2].max() - P[:, 2].min()
print(f"HEIGHT {h0:.5f} -> {h1:.5f} units ({(h1-h0)*UNIT_MM:+.3f} real mm)")

# restore materials, save, THEN render (the trap that broke 21_tone.py)
for i, ms in enumerate(ob.material_slots):
    ms.material = orig_mats[i]
bpy.ops.wm.save_as_mainfile(filepath=OUT_BLEND)
log(f"WROTE {OUT_BLEND}")
bpy.ops.export_scene.gltf(filepath=OUT_GLB, export_format='GLB', export_image_format='AUTO',
                          export_yup=True, export_apply=False, export_animations=False,
                          export_skins=False, export_morph=False)
log(f"WROTE {OUT_GLB} ({os.path.getsize(OUT_GLB)/1e6:.2f} MB)")

if REVIEW:
    os.makedirs(REVIEW, exist_ok=True)
    scn = bpy.context.scene
    wd = bpy.data.worlds.new("W")
    wd.color = (0.20, 0.20, 0.21)
    scn.world = wd
    for rot, e in (((55, 0, -35), 2.2), ((120, 0, 150), 1.0), ((85, 0, 35), 0.8)):
        ld = bpy.data.lights.new("s", 'SUN')
        ld.energy = e
        ld.use_shadow = False
        lo = bpy.data.objects.new("s", ld)
        lo.rotation_euler = tuple(math.radians(a) for a in rot)
        bpy.context.collection.objects.link(lo)
    cam = bpy.data.objects.new("Cam", bpy.data.cameras.new("Cam"))
    cam.data.lens = 70
    bpy.context.collection.objects.link(cam)
    scn.camera = cam
    scn.render.engine = 'BLENDER_EEVEE' if bpy.app.version >= (4, 2) else 'BLENDER_EEVEE_NEXT'
    scn.render.resolution_x, scn.render.resolution_y = 700, 1000
    clay = bpy.data.materials.new("Clay")
    clay.use_nodes = True
    cn = clay.node_tree.nodes["Principled BSDF"]
    cn.inputs["Base Color"].default_value = (0.80, 0.56, 0.42, 1)
    cn.inputs["Roughness"].default_value = 0.55

    def shoot(tag, yaw, span, ctr=(0.0, 0.0, 0.50), use_clay=True):
        for i, ms in enumerate(ob.material_slots):
            ms.material = clay if use_clay else orig_mats[i]
        y = math.radians(yaw)
        dist = span * 3.0
        cam.location = Vector(ctr) + Vector((math.sin(y) * dist, -math.cos(y) * dist, 0.0))
        cam.rotation_euler = (Vector(ctr) - cam.location).to_track_quat('-Z', 'Y').to_euler()
        scn.render.filepath = os.path.abspath(os.path.join(REVIEW, f"{tag}.png"))
        bpy.ops.render.render(write_still=True)
        log(f"render {tag}")

    shoot("front_clay", 0, 0.55)
    shoot("side_clay", 90, 0.55)
    shoot("back_clay", 180, 0.55)
    shoot("front_tex", 0, 0.55, use_clay=False)
    shoot("side_tex", 90, 0.55, use_clay=False)

print("V04_DONE")