I need to make .bytes to .gltf converter

Summary

The task at hand involves creating a Python function to convert animation data extracted from Shadow Fight 3, stored in.bytes format, into a.gltf or.glb container. The goal is to bypass the current CSV export method, which loses critical mathematical context, and directly wrap the original bytes into a glTF schema. This will enable standard 3D engines to read the animation while preserving the hierarchy and transformation logic.

Root Cause

The root cause of the issue lies in the loss of mathematical context when exporting the animation data to CSV. The engine’s internal coordinate math and bone hierarchy are not properly translated, resulting in unusable data. The current tool’s CSV export function is likely bugged, causing the data to become “random” and stripped of necessary context.

Why This Happens in Real Systems

This issue occurs in real systems due to the complexity of 3D game engines and the proprietary nature of their internal data formats. The engine’s use of fixed-point integers, compressed quaternions, and other optimized data structures can make it difficult to export data in a way that is compatible with standard 3D software. Additionally, the lack of documentation and limited access to the engine’s internal workings can make it challenging to develop a reliable export method.

Real-World Impact

The inability to export animation data in a usable format has significant real-world implications. It hinders the ability to reuse and repurpose game assets, limiting the potential for content creation and modification. Furthermore, it can also restrict the development of custom tools and mods, which can be a vital part of a game’s community and longevity.

Example or Code

import numpy as np

def bytes_to_gltf(bytes_data):
    # Define the Accessors and BufferViews
    accessors = []
    buffer_views = []

    # Assume the bytes data is structured as follows:
    # - 12 bytes per joint: 3 floats for translation, 4 floats for rotation (quaternion)
    joint_size = 12

    # Calculate the number of joints
    num_joints = len(bytes_data) // joint_size

    # Create a numpy array to store the joint data
    joint_data = np.zeros((num_joints, 7), dtype=np.float32)

    # Iterate over the bytes data and populate the joint array
    for i in range(num_joints):
        joint_offset = i * joint_size
        translation = np.frombuffer(bytes_data[joint_offset:joint_offset+12], dtype=np.float32)
        joint_data[i] = translation

    # Define the Accessor for the joint data
    accessors.append({
        "bufferView": 0,
        "byteOffset": 0,
        "componentType": 5126,  # FLOAT
        "count": num_joints,
        "type": "VEC3"
    })

    # Define the BufferView for the joint data
    buffer_views.append({
        "buffer": 0,
        "byteLength": joint_data.nbytes,
        "byteOffset": 0,
        "target": 34962  # ARRAY_BUFFER
    })

    # Create the glTF buffer
    buffer = joint_data.tobytes()

    # Return the glTF data
    return {
        "accessors": accessors,
        "bufferViews": buffer_views,
        "buffers": [buffer]
    }

How Senior Engineers Fix It

Senior engineers would approach this problem by first analyzing the internal data format of the game engine and understanding how the animation data is structured. They would then develop a custom export method that takes into account the specific requirements of the glTF format, including the definition of Accessors and BufferViews. By leveraging their expertise in 3D graphics and programming, they would be able to create a reliable and efficient export method that preserves the mathematical context and hierarchy of the animation data.

Why Juniors Miss It

Junior engineers may miss this issue due to a lack of experience with 3D graphics and game engines. They may not fully understand the complexities of the internal data formats and the requirements of the glTF schema, leading to incorrect or incomplete export methods. Additionally, they may not have the necessary programming skills to develop a custom export method, relying instead on existing tools and libraries that may not be suitable for the task.