Tiling is not broken. The problem with IE is that it pre-mutliplies colors by alpha, and then divides back, ignoring UNPACK_PREMULTIPLY_ALPHA_WEBGL being false. Closer your alpha to 0, more precision loss occurs on IE. Try separating color and alpha to different textures.
又一个GITHUB上的相关信息： Some implementations of HTMLCanvasElement's CanvasRenderingContext2D store color values internally in premultiplied form. If such a canvas is uploaded to a WebGL texture with the UNPACK_PREMULTIPLY_ALPHA_WEBGL pixel storage parameter set to false, the color channels will have to be un-multiplied by the alpha channel, which is a lossy operation.
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InJoins
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在我的IOS手机上，带ALPHA通道的贴图的颜色先是被预乘了ALPHA，然后又除以了ALPHA，所以，在ALPHA比较低的地方，像素颜色变的很暗。
LAYA引擎的大神，能研究一下这个问题吗？（在PS里做一张半透明贴图，RGB拉一个渐变，ALPHA也拉一个渐变，然后用SUPERPNG导出；或者ALPHA拉在蒙板里，用PS自己的PNG格式导出也行；然后赋值给一个模型，就可以看到问题）
Tiling is not broken. The problem with IE is that it pre-mutliplies colors by alpha, and then divides back, ignoring UNPACK_PREMULTIPLY_ALPHA_WEBGL being false. Closer your alpha to 0, more precision loss occurs on IE. Try separating color and alpha to different textures.
InJoins
赞同来自:
Some implementations of HTMLCanvasElement's CanvasRenderingContext2D store color values internally in premultiplied form. If such a canvas is uploaded to a WebGL texture with the UNPACK_PREMULTIPLY_ALPHA_WEBGL pixel storage parameter set to false, the color channels will have to be un-multiplied by the alpha channel, which is a lossy operation.