没有强烈变形的纹理球体 [英] Textured spheres without strong distortion

问题描述

上次在UFO中，我已经看过几次比赛中质地良好的球，行星和其他球形物体:后果.如果只是将纹理像u和w坐标那样在纬度/经度中飞溅，则极点会出现很多难看的纹理变形.

I've seen well-textured balls, planets, and other spherical objects in couple of games, last time in UFO: aftermath. If you just splatter a texture into latitude/longditude as u and w -coordinates you'll get lots of ugly texture distortion to poles.

我可以认为自己是实现失真最小的球形贴图的一种方法.通过映射为三角形而不是正方形.但是我不知道任何算法.如何为此类球体生成顶点和纹理坐标?

I can think myself an one way to implement a spherical map with minimum distortion. By mapping in triangles instead of squares. But I don't know any algorithms. How to produce vertices and texture coordinates for such spheres?

此外，我没有从简单的平面正方形地图生成完整的球形地图的方法.在绘制此类地图时是否有一些直观的方法而没有真正的麻烦?

Also, I don't see a way to generate a complete spherical map from a simple flat square map. Is there some intuitive way on drawing such maps without real trouble?

但是，还有其他算法可以在不变形或变形最小的情况下渲染球体吗?

Though, is there other algorithms to render a sphere without or with minimal distortion?

光线跟踪和栅格化算法都很有趣.

Both raytracing and rasterising algorithms are interesting.

推荐答案

毛球定理指出，在没有任何使纹理变形的极点的情况下，不可能在球体上定义连续的纹理坐标.

The hairy ball theorem states that it is impossible to define continuous texture coordinates on a sphere without any poles that distort the texture.

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