games-creater/spine_builder.py

"""把一张角色透明图变成可在 Cocos(Spine 运行时) 播放的骨骼动画三件套：
  <id>.json   (skeleton 数据)
  <id>.atlas  (图集描述)
  <id>.png    (贴图)

v1 策略：单骨骼 + 程序化 squash/stretch 抖动（果冻 jiggle）。
不需要拆件，纯靠对整张图做挤压/拉伸/旋转关键帧，即可得到真实可见的动画。
后续要做多部件骨骼，在 build_skeleton_json 里扩展 bones/slots/skins 即可。
"""

import json
import math
import os
from PIL import Image


# ---------- 程序化动画生成 ----------

def _scale_keys(samples):
    return [{"time": round(t, 4), "x": round(x, 4), "y": round(y, 4)} for (t, x, y) in samples]


def _rotate_keys(samples):
    return [{"time": round(t, 4), "value": round(v, 4)} for (t, v) in samples]


def jiggle_idle(period=1.2, amp=0.06):
    """轻微呼吸式果冻抖动，循环。"""
    samples = []
    steps = 8
    for i in range(steps + 1):
        t = period * i / steps
        phase = 2 * math.pi * i / steps
        x = 1 + amp * math.sin(phase)
        y = 1 - amp * math.sin(phase)   # x 胖 y 就矮，保持体积感
        samples.append((t, x, y))
    return {"scale": _scale_keys(samples)}


def jiggle_win(period=0.9, amp=0.16):
    """中奖：更大幅度弹跳 + 轻微摇摆。"""
    scale_samples, rot_samples = [], []
    steps = 6
    for i in range(steps + 1):
        t = period * i / steps
        phase = 2 * math.pi * i / steps
        decay = 1 - (i / steps) * 0.3
        x = 1 + amp * decay * math.cos(phase)
        y = 1 - amp * decay * math.cos(phase)
        scale_samples.append((t, x, y))
        rot_samples.append((t, 6 * decay * math.sin(phase)))
    return {"scale": _scale_keys(scale_samples), "rotate": _rotate_keys(rot_samples)}


def attack():
    """攻击：先蓄力后猛冲再回正（不循环）。"""
    scale = [(0, 1, 1), (0.12, 0.85, 1.12), (0.26, 1.22, 0.85), (0.5, 1, 1)]
    rot = [(0, 0), (0.12, -8), (0.26, 13), (0.5, 0)]
    return {"scale": _scale_keys(scale), "rotate": _rotate_keys(rot)}


def hurt():
    """受击：快速回缩 + 衰减摇摆（不循环）。"""
    scale = [(0, 1, 1), (0.06, 1.14, 0.88), (0.4, 1, 1)]
    rot = [(0, 0), (0.08, -11), (0.18, 8), (0.28, -4), (0.4, 0)]
    return {"scale": _scale_keys(scale), "rotate": _rotate_keys(rot)}


def bounce_in():
    """入场：从无到有弹入，带过冲（不循环）。"""
    scale = [(0, 0, 0), (0.28, 1.15, 0.9), (0.4, 0.95, 1.08), (0.5, 1, 1)]
    rot = [(0, -12), (0.28, 4), (0.5, 0)]
    return {"scale": _scale_keys(scale), "rotate": _rotate_keys(rot)}


ANIM_FACTORY = {
    "idle": jiggle_idle,
    "win": jiggle_win,
    "attack": attack,
    "hurt": hurt,
    "bounce_in": bounce_in,
}


# ---------- 图片处理 ----------

def remove_bg(img, bright=200, sat=38):
    """自动去背：把"亮且低饱和（白/浅灰/奶油）且与四边连通"的像素抠成透明。
    用边界连通传播，所以果冻身上被颜色包住的白高光/白眼睛不会被误删。
    纯 numpy 实现，不依赖 scipy；没装 numpy 时退回 PIL 泛洪。"""
    img = img.convert("RGBA")
    try:
        import numpy as np
        arr = np.array(img)
        rgb = arr[:, :, :3].astype(np.int16)
        mx = rgb.max(axis=2); mn = rgb.min(axis=2)
        bgcand = (mn >= bright) & ((mx - mn) <= sat)        # 背景候选：亮 + 低饱和
        # 从靠近四边的一圈带里取种子（最外 1~2px 常是透明黑边，要往里一点）
        H, W = bgcand.shape
        band = max(10, H // 80)
        seed = np.zeros_like(bgcand)
        seed[:band, :] = True; seed[-band:, :] = True
        seed[:, :band] = True; seed[:, -band:] = True
        bg = bgcand & seed
        for _ in range(2000):                                # 从四边向内连通传播
            prev = int(bg.sum())
            new = bg.copy()
            new[1:, :] |= bg[:-1, :]; new[:-1, :] |= bg[1:, :]
            new[:, 1:] |= bg[:, :-1]; new[:, :-1] |= bg[:, 1:]
            new &= bgcand
            bg = new
            if int(bg.sum()) == prev:
                break
        # 羽化一圈，柔化果冻边缘的白色硬边
        edge = bg.copy()
        edge[1:, :] |= bg[:-1, :]; edge[:-1, :] |= bg[1:, :]
        edge[:, 1:] |= bg[:, :-1]; edge[:, :-1] |= bg[:, 1:]
        fringe = edge & ~bg & (mn >= bright - 30)
        arr[bg, 3] = 0
        arr[fringe, 3] = (arr[fringe, 3] * 0.35).astype(arr.dtype)
        return Image.fromarray(arr, "RGBA")
    except Exception:
        return _floodfill_bg(img, 236)


def _floodfill_bg(img, thresh):
    """纯 PIL 兜底：先把透明区垫白（否则透明边会被当种子），再从四边泛洪近白背景。"""
    from PIL import ImageDraw
    w, h = img.size
    rgb = Image.new("RGB", (w, h), (255, 255, 255))
    rgb.paste(img.convert("RGB"), mask=img.split()[3])   # 用 alpha 贴，透明处保持白
    tol = 255 - thresh + 10
    seeds = [(0, 0), (w - 1, 0), (0, h - 1), (w - 1, h - 1),
             (w // 2, 0), (w // 2, h - 1), (0, h // 2), (w - 1, h // 2)]
    for s in seeds:
        ImageDraw.floodfill(rgb, s, (255, 0, 255), thresh=tol)
    try:
        import numpy as np
        mask = (np.array(rgb) == (255, 0, 255)).all(axis=2)
        arr = np.array(img.convert("RGBA"))
        arr[mask, 3] = 0
        return Image.fromarray(arr, "RGBA")
    except Exception:
        out = img.convert("RGBA"); po, pr = out.load(), rgb.load()
        for y in range(h):
            for x in range(w):
                if pr[x, y] == (255, 0, 255):
                    r, g, b, _ = po[x, y]; po[x, y] = (r, g, b, 0)
        return out


def trim_to_content(img, pad=4):
    """裁掉透明边，留一点 padding。返回裁好的 RGBA。"""
    bbox = img.getbbox()
    if bbox:
        img = img.crop(bbox)
    if pad:
        w, h = img.size
        canvas = Image.new("RGBA", (w + pad * 2, h + pad * 2), (0, 0, 0, 0))
        canvas.paste(img, (pad, pad))
        img = canvas
    return img


# ---------- 三件套生成 ----------

def write_atlas(atlas_path, png_name, region_name, w, h):
    """libgdx 传统格式 atlas，单区域，兼容 Cocos spine 运行时。"""
    lines = [
        png_name,
        f"size: {w},{h}",
        "format: RGBA8888",
        "filter: Linear,Linear",
        "repeat: none",
        region_name,
        "  rotate: false",
        "  xy: 0, 0",
        f"  size: {w}, {h}",
        f"  orig: {w}, {h}",
        "  offset: 0, 0",
        "  index: -1",
        "",
    ]
    with open(atlas_path, "w", encoding="utf-8") as f:
        f.write("\n".join(lines))


def build_skeleton_json(char_id, w, h, animations):
    """单骨骼 region 绑定 + 程序化动画。骨骼原点在底部中心，便于"果冻不离地"挤压。"""
    anims = {}
    for name in animations:
        factory = ANIM_FACTORY.get(name)
        if factory is None:
            continue
        anims[name] = {"bones": {"body": factory()}}
    if not anims:
        anims["idle"] = {"bones": {"body": jiggle_idle()}}

    return {
        "skeleton": {
            "hash": char_id,
            "spine": "4.0.00",
            "x": -w / 2.0, "y": 0, "width": float(w), "height": float(h),
            "images": "./", "audio": "",
        },
        "bones": [
            {"name": "root"},
            {"name": "body", "parent": "root"},
        ],
        "slots": [
            {"name": "body", "bone": "body", "attachment": "body"},
        ],
        "skins": [
            {
                "name": "default",
                "attachments": {
                    "body": {
                        "body": {"x": 0, "y": h / 2.0, "width": w, "height": h}
                    }
                },
            }
        ],
        "animations": anims,
    }


def anim_data(animations):
    """返回给网页预览用的动画关键帧（与 skeleton 里同一套数据）。
    结构: { name: {"duration": t, "scale": [{time,x,y}...], "rotate": [{time,value}...]} }
    """
    out = {}
    for name in animations:
        factory = ANIM_FACTORY.get(name)
        if factory is None:
            continue
        d = factory()
        scale = d.get("scale", [])
        rotate = d.get("rotate", [])
        times = [k["time"] for k in scale] + [k["time"] for k in rotate]
        out[name] = {
            "duration": max(times) if times else 1.0,
            "scale": scale,
            "rotate": rotate,
        }
    if not out:
        d = jiggle_idle()
        out["idle"] = {"duration": d["scale"][-1]["time"], "scale": d["scale"], "rotate": []}
    return out


def build_character(char_id, image, out_dir, animations):
    """主入口：image(PIL RGBA) -> out_dir/<id>.{json,atlas,png}。返回 png 路径。"""
    os.makedirs(out_dir, exist_ok=True)
    img = trim_to_content(remove_bg(image))   # 先自动去白底，再裁透明边
    w, h = img.size

    png_name = f"{char_id}.png"
    png_path = os.path.join(out_dir, png_name)
    img.save(png_path)

    write_atlas(os.path.join(out_dir, f"{char_id}.atlas"), png_name, "body", w, h)

    skel = build_skeleton_json(char_id, w, h, animations)
    with open(os.path.join(out_dir, f"{char_id}.json"), "w", encoding="utf-8") as f:
        json.dump(skel, f, ensure_ascii=False, indent=2)

    return png_path