# -*- coding: utf-8 -*-
"""由 box_of_nails 方块贴图(64x64 UV展开图)生成 16x16 的物品图标。

采用等轴测投影组合盒子可见的三个面（顶面 + 正面 + 右侧面），
源贴图中三个面所在的像素区域（由 blockbench 模型 UV 推出）：
    正面 north  px (8, 8)  - (18, 13)   10 x 5
    右侧 east   px (0, 8)  - (8, 13)     8 x 5
    顶面 up     px (8, 13) - (18, 21)   10 x 8
盒子模型尺寸: 宽 10 单位(x) x 高 5 单位(y) x 深 8 单位(z)，1 单位 = 1 贴图像素。
"""
import math
import os
from PIL import Image

ROOT = r"e:\MCStudioDownload\work\3027246179@qq.com\Cpp\AddOn\0aaaa4f2f16c46e8964025a5ab0ecc02"
RES = os.path.join(ROOT, "resource_pack_t7eJjrxY")
SRC = os.path.join(RES, "textures", "blocks", "box_of_nails.png")
DST = os.path.join(RES, "textures", "items", "box_of_nails.png")

OUT = 16          # 最终图标边长
SS = 4            # 超采样倍数
SIZE = OUT * SS   # 渲染画布边长

TEX_FRONT = (8, 8, 18, 13)     # 正面 north
TEX_WEST = (18, 8, 26, 13)     # 左侧面 west
TEX_TOP = (8, 13, 18, 21)      # 顶面 up

W, H, D = 10.0, 5.0, 8.0   # 盒子宽/高/深（模型单位）


def rasterize(dst, src, origin, uvec, vvec, rect):
    """把源贴图矩形 rect 以平行四边形(origin + s*uvec + t*vvec)填到 dst。"""
    x0, y0, x1, y1 = rect
    ox, oy = origin
    ux, uy = uvec
    vx, vy = vvec
    det = ux * vy - uy * vx
    if abs(det) < 1e-9:
        return
    corners = [origin, (ox + ux, oy + uy), (ox + ux + vx, oy + uy + vy), (ox + vx, oy + vy)]
    minx = max(0, int(math.floor(min(c[0] for c in corners))))
    maxx = min(dst.width - 1, int(math.ceil(max(c[0] for c in corners))))
    miny = max(0, int(math.floor(min(c[1] for c in corners))))
    maxy = min(dst.height - 1, int(math.ceil(max(c[1] for c in corners))))
    px = dst.load()
    spx = src.load()
    sw, sh = src.size
    for py in range(miny, maxy + 1):
        dy = py + 0.5 - oy
        for pxx in range(minx, maxx + 1):
            dx = pxx + 0.5 - ox
            s = (vy * dx - vx * dy) / det
            t = (-uy * dx + ux * dy) / det
            if s < 0.0 or s >= 1.0 or t < 0.0 or t >= 1.0:
                continue
            sx = int(x0 + s * (x1 - x0))
            sy = int(y0 + t * (y1 - y0))
            sx = min(max(sx, 0), sw - 1)
            sy = min(max(sy, 0), sh - 1)
            px[pxx, py] = spx[sx, sy]


def main():
    src = Image.open(SRC).convert("RGBA")
    dst = Image.new("RGBA", (SIZE, SIZE), (0, 0, 0, 0))

    cx = math.cos(math.radians(30.0))
    cy = math.sin(math.radians(30.0))
    # 画布内每模型单位对应的像素数（保证盒子完整落在画布内）
    margin = 4
    u = min((SIZE - 2 * margin) / ((W + D) * cx),
            (SIZE - 2 * margin) / ((W + D) * cy + H))

    wv = (W * u * cx, -W * u * cy)      # 宽度方向 x（右后上）
    dv = (-D * u * cx, -D * u * cy)     # 深度方向 z（左后上）
    vv = (0.0, H * u)                   # 竖直向下

    # 前上顶点 F（俯视时最靠近观察者的角），整体居中
    content_w = (W + D) * u * cx
    content_h = (W + D) * u * cy + H * u
    fx = (SIZE - content_w) / 2.0 + D * u * cx
    fy = (SIZE - content_h) / 2.0 + (W + D) * u * cy
    f = (fx, fy)

    rasterize(dst, src, f, dv, vv, TEX_WEST)      # 左侧面
    rasterize(dst, src, f, wv, vv, TEX_FRONT)     # 正面
    rasterize(dst, src, f, wv, dv, TEX_TOP)       # 顶面

    icon = dst.resize((OUT, OUT), Image.BOX)
    os.makedirs(os.path.dirname(DST), exist_ok=True)
    icon.save(DST)
    print("icon ->", DST, icon.size)


if __name__ == "__main__":
    main()