82 lines
2.4 KiB
TypeScript
82 lines
2.4 KiB
TypeScript
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/**
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* UV Coordinate Helper
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* UV 坐标辅助工具
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*
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* 引擎使用图像坐标系：
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* Engine uses image coordinate system:
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* - 原点 (0, 0) 在左上角 | Origin at top-left
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* - V 轴向下增长 | V-axis increases downward
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* - UV 格式：[u0, v0, u1, v1] 其中 v0 < v1
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*/
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export class UVHelper {
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/**
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* Calculate UV coordinates for a texture region
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* 计算纹理区域的 UV 坐标
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*/
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static calculateUV(
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imageRect: { x: number; y: number; width: number; height: number },
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textureSize: { width: number; height: number }
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): [number, number, number, number] {
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const { x, y, width, height } = imageRect;
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const { width: tw, height: th } = textureSize;
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return [
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x / tw, // u0
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y / th, // v0
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(x + width) / tw, // u1
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(y + height) / th // v1
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];
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}
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/**
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* Calculate UV coordinates for a tile in a tileset
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* 计算 tileset 中某个 tile 的 UV 坐标
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*/
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static calculateTileUV(
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tileIndex: number,
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tilesetInfo: {
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columns: number;
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tileWidth: number;
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tileHeight: number;
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imageWidth: number;
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imageHeight: number;
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margin?: number;
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spacing?: number;
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}
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): [number, number, number, number] | null {
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if (tileIndex < 0) return null;
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const {
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columns,
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tileWidth,
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tileHeight,
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imageWidth,
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imageHeight,
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margin = 0,
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spacing = 0
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} = tilesetInfo;
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const col = tileIndex % columns;
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const row = Math.floor(tileIndex / columns);
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const x = margin + col * (tileWidth + spacing);
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const y = margin + row * (tileHeight + spacing);
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return this.calculateUV(
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{ x, y, width: tileWidth, height: tileHeight },
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{ width: imageWidth, height: imageHeight }
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);
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}
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static validateUV(uv: [number, number, number, number]): boolean {
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const [u0, v0, u1, v1] = uv;
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return u0 >= 0 && u0 <= 1 && u1 >= 0 && u1 <= 1 &&
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v0 >= 0 && v0 <= 1 && v1 >= 0 && v1 <= 1 &&
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u0 < u1 && v0 < v1;
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}
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static debugPrint(uv: [number, number, number, number], label?: string): void {
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const prefix = label ? `[${label}] ` : '';
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console.log(`${prefix}UV: [${uv.map(n => n.toFixed(4)).join(', ')}]`);
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}
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}
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