We can understand it by comparing the effects of different formats.
Effect of uncompressed RGBA32 format (all GPU support) Please ignore the seam problem, that is the art of UV to show wrong ...
ATC compression format (format supported by the Adreno series GPU) The naked eye almost does not make the difference, the saturation has slightly reduced ps:dxt, the PVR effect also is similar, here does not post, the interested person can test under
And finally the evil ETC1 (all GPU support) Note the line of the Red Arrow, which appears only in the ETC1 format, suspect that its compression algorithm is defective, but the specific reason has not been investigated
Conclusion this thing can not be used at all Ah, especially the contrast ratio of larger pictures, will produce a variety of inexplicable flaws. Very puzzled about some projects with ETC1 is how to deal with this effect, asked the next company in the boss of the other project group, the proposal is replaced with RGBA16 or RGB16 plus reduce the resolution is better than with the ETC1 effect.
Ps:opengl es Damn, this is the only default supported compression format ETC1 not only has no alpha channel, but also produces such a large defect after compression ...
From for notes (Wiz)
Why is the ETC1 texture format never used in our project?
