这是纹理采样器的正确行为。

This is correct behavior of texture sampler.

让我解释一下。使用 GL_LINEAR 采样的纹理时，GPU将采用与附近像素混合的像素的平均颜色（这就是为什么你没有像 GL_NEAREST那样看到像素化的原因模式 - 像素模糊不清）。
和 GL_REPEAT 模式纹理坐标将从0换算为1，反之亦然，与附近的像素混合（即在极坐标中，它将与纹理的另一面混合）。 GL_CLAMP_TO_EDGE 可防止此包装行为，并且像素不会与纹理对面的像素混合。

Let me explain this. When you use textures with GL_LINEAR sampling GPU will take an average color of pixel blended with nearby pixels (that's why you don't see pixelation as with GL_NEAREST mode - pixels are blurred instead). And with GL_REPEAT mode texture coordinates will wrap from 0 to 1 and vice versa, blending with nearby pixels (i.e. in extreme coordinates it will blend with opposite side of texture). GL_CLAMP_TO_EDGE prevents this wrapping behavior, and pixels won't blend with pixels from opposite side of texture.

希望我的解释清楚。