k4/gltf2tok3.py
2025-01-26 20:26:43 +02:00

394 lines
11 KiB
Python
Executable File

#!/usr/bin/env python3
import pygltflib
import sys
import numpy
import os
import base64
import pathlib
import struct
def mat3_to_quat(m):
trace = numpy.trace(m)
if trace >= 0:
r = (1 + trace) ** 0.5
rinv = 0.5 / r
q0 = rinv * (m[1, 2] - m[2, 1])
q1 = rinv * (m[2, 0] - m[0, 2])
q2 = rinv * (m[0, 1] - m[1, 0])
q3 = r * 0.5
elif m[0, 0] >= m[1, 1] and m[0, 0] >= m[2, 2]:
r = (1 - m[1, 1] - m[2, 2] + m[0, 0]) ** 0.5
rinv = 0.5 / r
q0 = r * 0.5
q1 = rinv * (m[0, 1] + m[1, 0])
q2 = rinv * (m[0, 2] + m[2, 0])
q3 = rinv * (m[1, 2] - m[2, 1])
elif m[1, 1] >= m[2, 2]:
r = (1 - m[0, 0] - m[2, 2] + m[1, 1]) ** 0.5
rinv = 0.5 / r
q0 = rinv * (m[0, 1] + m[1, 0])
q1 = r * 0.5
q2 = rinv * (m[1, 2] + m[2, 1])
q3 = rinv * (m[2, 0] - m[0, 2])
else:
r = (1 - m[0, 0] - m[1, 1] + m[2, 2]) ** 0.5
rinv = 0.5 / r
q0 = rinv * (m[0, 2] + m[2, 0])
q1 = rinv * (m[1, 2] + m[2, 1])
q2 = r * 0.5
q3 = rinv * (m[0, 1] - m[1, 0])
q = numpy.array([q0, q1, q2, q3])
if q[3] < 0:
q = -q
return q
def mat3_from_quat(q):
b, c, d, a = q[0], q[1], q[2], q[3]
return numpy.array([
[a ** 2 + b ** 2 - c ** 2 - d ** 2, 2 * b * c + 2 * a * d, 2 * b * d - 2 * a * c],
[2 * b * c - 2 * a * d, a ** 2 - b ** 2 + c ** 2 - d ** 2, 2 * c * d - 2 * a * b],
[2 * b * d - 2 * a * c, 2 * c * d + 2 * a * b, a ** 2 - b ** 2 - c ** 2 + d ** 2],
])
def mat4_decompose(m):
translation = m[3][:3]
rs_matrix = m[:3, :3]
scale = (rs_matrix ** 2).sum(-1) ** 0.5
rs_matrix[0] /= scale[0]
rs_matrix[1] /= scale[1]
rs_matrix[2] /= scale[2]
if numpy.dot(numpy.cross(m[0][:3], m[1][:3]), m[2][:3]) < 0:
rs_matrix[0] *= -1
rs_matrix[1] *= -1
rs_matrix[2] *= -1
scale *= -1
return translation, mat3_to_quat(rs_matrix), scale
def mat4_compose(t, r, s):
m = numpy.zeros((4, 4))
rm = mat3_from_quat(r) if r is not None else numpy.eye(3)
if s is not None:
rm[0] *= s[0]
rm[1] *= s[1]
rm[2] *= s[2]
m[:3, :3] = rm
if t is not None:
m[3][:3] = t
m[3][3] = 1
return m
def lerp(a, b, alpha):
return a + (b - a) * alpha
def slerp(a, b, alpha):
angle = numpy.arccos(min(1, max(-1, numpy.dot(a, b))))
denominator = numpy.sin(angle)
if abs(denominator) < 0.000001:
return lerp(a, b, alpha)
return (a * numpy.sin((1 - alpha) * angle) + b * numpy.sin(alpha * angle)) / denominator
TYPE_SIZES = {
"SCALAR": 1,
"VEC2": 2,
"VEC3": 3,
"VEC4": 4,
"MAT2": 4,
"MAT4": 16,
"MAT3": 9,
pygltflib.FLOAT: 4,
pygltflib.UNSIGNED_INT: 4,
pygltflib.UNSIGNED_SHORT: 2,
pygltflib.UNSIGNED_BYTE: 1,
pygltflib.SHORT: 2,
pygltflib.BYTE: 1,
}
GLTF_NUMPY_MAPPING = {
pygltflib.FLOAT: numpy.float32,
pygltflib.UNSIGNED_INT: numpy.uint32,
pygltflib.UNSIGNED_SHORT: numpy.uint16,
pygltflib.UNSIGNED_BYTE: numpy.uint8,
pygltflib.SHORT: numpy.int16,
pygltflib.BYTE: numpy.int8,
}
errors = []
def err(s):
errors.append(s)
def err_barrier():
for e in errors:
print(e)
if os.name == "nt" and "PROMPT" not in os.environ:
raw_input()
if len(errors):
sys.exit(1)
for input_filename in sys.argv[1:]:
gltf = pygltflib.GLTF2().load(input_filename)
gltf.convert_buffers(pygltflib.BufferFormat.DATAURI)
def get_nd(acc_idx):
if acc_idx == None:
return None
accessor = gltf.accessors[acc_idx]
buf_view = gltf.bufferViews[accessor.bufferView]
buf = gltf.buffers[buf_view.buffer]
uri = buf.uri
if "base64," in uri:
buf_data = base64.decodebytes(buf.uri.split("base64,")[-1].encode())
else:
with open(uri, "rb") as urifile:
buf_data = urifile.read()
start = buf_view.byteOffset + accessor.byteOffset
array = numpy.frombuffer(buf_data[start : start + accessor.count * TYPE_SIZES[accessor.type] * TYPE_SIZES[accessor.componentType]], dtype = GLTF_NUMPY_MAPPING[accessor.componentType])
return numpy.reshape(array, (array.shape[0] // TYPE_SIZES[accessor.type], TYPE_SIZES[accessor.type]))
def get(acc_idx):
array = get_nd(acc_idx)
return array.ravel() if array is not None else None
mesh_nodes = [n for n in gltf.nodes if n.mesh != None]
if len(mesh_nodes) > 1:
err("All meshes except first are ignored")
mesh_node = mesh_nodes[0]
mesh = gltf.meshes[mesh_node.mesh]
skin = gltf.skins[mesh_node.skin] if mesh_node.skin != None else None
k3result = {
"animations": [],
"bones": [],
"meshes": [],
}
for primitive in mesh.primitives:
material_name = ""
if primitive.material is not None:
material_name = gltf.materials[primitive.material].name
if not material_name:
err("Missing material name")
material_name = ""
else:
err("Missing material information")
mehs = {
"positions": get_nd(primitive.attributes.POSITION),
"normals": get_nd(primitive.attributes.NORMAL),
"uvs": get_nd(primitive.attributes.TEXCOORD_0),
"colors": get_nd(primitive.attributes.COLOR_0),
"boneids": get_nd(primitive.attributes.JOINTS_0),
"boneweights": get_nd(primitive.attributes.WEIGHTS_0),
"indices": get(primitive.indices),
"material_name": material_name
}
if mehs["normals"] is None:
err("Missing normal data")
if mehs["uvs"] is None:
err("Missing UVs")
k3result["meshes"].append(mehs)
if len(skin.joints) > 255:
err("Bone maximum is 255")
err_barrier()
joint_gltf_to_k3_id_mapping = {}
joint_k3_to_gltf_id_mapping = {}
if skin:
# Topologically sort joints just in case they aren't
joint_parents = {i: next((j for j in skin.joints if i in gltf.nodes[j].children), None) for i in skin.joints}
joint_graph = joint_parents.copy()
while len(k3result["bones"]) != len(skin.joints):
minimal_elements = [k for k, v in joint_graph.items() if v == None]
for j in minimal_elements:
joint_gltf_to_k3_id_mapping[j] = len(k3result["bones"])
joint_k3_to_gltf_id_mapping[len(k3result["bones"])] = j
k3result["bones"].append({
"parent": joint_gltf_to_k3_id_mapping.get(joint_parents[j], 255),
"bind": mat4_compose(gltf.nodes[j].translation, gltf.nodes[j].rotation, gltf.nodes[j].scale)
})
for k, v in joint_graph.copy().items():
if v in minimal_elements:
joint_graph[k] = None
if v == None:
del joint_graph[k]
for k3b in k3result["bones"]:
if k3b["parent"] != 255:
k3b["bind"] = k3result["bones"][k3b["parent"]]["bind"] @ k3b["bind"]
for anim_idx, animation in enumerate(gltf.animations):
timelines = {}
duration = 0
# Fill timelines from GLTF data
for channel in animation.channels:
target_node = channel.target.node
if target_node not in joint_gltf_to_k3_id_mapping:
# Not a bone
continue
sampler = animation.samplers[channel.sampler]
times = get(sampler.input)
values = get_nd(sampler.output)
timeline = []
for t, v in zip(times, values):
timeline.append((t, v))
duration = max(duration, t)
timeline.sort(key = lambda kf: kf[0])
timelines.setdefault(joint_gltf_to_k3_id_mapping[target_node], {})[channel.target.path] = timeline
# Make sure that all bones & transform types have at least one keyframe
for bone_id, k3b in enumerate(k3result["bones"]):
bone_timelines = timelines.setdefault(bone_id, {})
l = bone_timelines.setdefault("translation", [])
if len(l) == 0:
l.append((0, numpy.array([0, 0, 0])))
l = bone_timelines.setdefault("rotation", [])
if len(l) == 0:
l.append((0, numpy.array([0, 0, 0, 1])))
l = bone_timelines.setdefault("scale", [])
if len(l) == 0:
l.append((0, numpy.array([1, 1, 1])))
# Playback and store all bone transforms per frame as k3 format needs
fps = 30
frame_interval = 1 / fps
frame_times = numpy.arange(0, duration, frame_interval)
k3anim = {"id": anim_idx, "fps": fps, "frames": []}
for t in frame_times:
bone_transfs = []
for bone_id, k3b in enumerate(k3result["bones"]):
def dothing(transf_type, interp_func):
tm = timelines[bone_id][transf_type]
k1 = [k for k in range(len(tm)) if tm[k][0] <= t]
k2 = [k for k in range(len(tm)) if tm[k][0] > t]
k1 = max(k1) if len(k1) else 0
k2 = min(k2) if len(k2) else len(tm) - 1
alpha = (t - tm[k1][0]) / (tm[k2][0] - tm[k1][0]) if tm[k2][0] != tm[k1][0] else 0
return interp_func(tm[k1][1], tm[k2][1], alpha)
translation = dothing("translation", lerp)
rotation = dothing("rotation", slerp)
scale = dothing("scale", lerp)
bone_transfs.append((translation, rotation))
k3anim["frames"].append(bone_transfs)
k3result["animations"].append(k3anim)
# Finally, output
output_filename = pathlib.Path(input_filename).with_suffix(".k3m")
with open(output_filename, "wb") as f:
f.write(b"K3M ")
vertex_count = sum([len(mesh["positions"]) for mesh in k3result["meshes"]])
index_count = sum([len(mesh["indices"]) for mesh in k3result["meshes"]])
f.write(struct.pack("I", vertex_count))
f.write(struct.pack("I", index_count))
f.write(struct.pack("B", len(k3result["bones"])))
colorsEnabled = any([mesh["colors"] is not None for mesh in k3result["meshes"]])
# todo
colorsEnabled = False
f.write(struct.pack("B", 1 if colorsEnabled else 0))
f.write(struct.pack("H", len(k3result["animations"])))
for k3b in k3result["bones"]:
f.write(struct.pack("16f", *numpy.reshape(numpy.linalg.inv(k3b["bind"]), (16,))))
for k3b in k3result["bones"]:
f.write(struct.pack("B", k3b["parent"]))
for mesh in k3result["meshes"]:
f.write(mesh["positions"][:, :3].astype(numpy.float32).ravel().tobytes())
for mesh in k3result["meshes"]:
normals = mesh["normals"][:, :3].astype(numpy.float32)
for i in range(len(normals)):
normals[i] /= numpy.max(numpy.abs(normals[i]))
normals[i] *= 127
f.write(normals.astype(numpy.int8).ravel().tobytes())
for mesh in k3result["meshes"]:
f.write(mesh["uvs"][:, :2].astype(numpy.float32).ravel().tobytes())
if mesh["boneids"] is not None:
for mesh in k3result["meshes"]:
f.write(mesh["boneids"][:, :4].astype(numpy.int8).ravel().tobytes())
for mesh in k3result["meshes"]:
f.write((mesh["boneweights"][:, :4].astype(numpy.float32) * 65535).astype(numpy.int16).ravel().tobytes())
if colorsEnabled:
# TODO
#for mesh in k3result["colors"]:
# f.write(mesh["colors"][:, :4])
pass
for mesh in k3result["meshes"]:
f.write(mesh["indices"].astype(numpy.uint16).tobytes())
f.write(struct.pack("H", len(k3result["meshes"])))
offset = 0
for mesh in k3result["meshes"]:
ind_count = len(mesh["indices"])
f.write(struct.pack("2H", offset, ind_count))
f.write(mesh["material_name"].encode("UTF-8") + b'\x00')
offset += ind_count
for anim in k3result["animations"]:
f.write(struct.pack("4H", anim["id"], len(anim["frames"]), anim["fps"], 0))
for frame in anim["frames"]:
for bone_idx in range(len(k3result["bones"])):
f.write(struct.pack("4f", frame[bone_idx][0][0], frame[bone_idx][0][1], frame[bone_idx][0][2], 1))
f.write(struct.pack("4f", *frame[bone_idx][1]))