werner.poetzelberger Posted September 4, 2013 Posted September 4, 2013 Hello, since I am working with Normal Maps on decals and terrain in the editor I am having really hard times getting a good result, because of one 'strange' thing. When I apply a normal map on a deferred decal and I rotate the decal, the shading of the whole decal changes. Please look at the image. The 'normal ok' is just a rotation which gives a visual result which is 'bright', the image 'normal_bad' is the same decal only rotated some degree. I am using a Normal Map which I generate from the diffuse texture using the 'Crazy Bump' Tool. I guess it has something to do with the texture itself? Thank you for answers. Best. Werner Ok, I think I found the problem. I must not use DXT1 compression which creates this crazy effect. Which compression may I use instead? Or should i stick to RGB8 ?
ulf.schroeter Posted September 4, 2013 Posted September 4, 2013 UNIGINE Documentation Normal map: It uses an LA format which stores two components of a normal. The third component is calculated from the stored components. Compression of normal maps with DXT1 is in general no good idea, but there are some formats like ATI2N optimized for 2-component normal compression. (though I don't know if this format is supported by non-ATI hardware)
werner.poetzelberger Posted September 4, 2013 Author Posted September 4, 2013 So, I should use A8L8 ? This is povided by the Nvidia Ps Exporter as well as in Crazy Bump. Cheers. werner
ulf.schroeter Posted September 4, 2013 Posted September 4, 2013 Just try it. Also have a look at this post, maybe ATI2N normal map texture compression is usable without rendering artifacts. 1
demostenes Posted September 5, 2013 Posted September 5, 2013 Compression of normal maps with DXT1 is in general no good idea, but there are some formats like ATI2N optimized for 2-component normal compression. (though I don't know if this format is supported by non-ATI hardware) Yes, even non ati HW can display it, it will be only slower, i think some decompression must happen (on dx9 to RGBA8, on OGL to LA8 ). It is recommended format for nomal maps by Unigine team (texture converter automatically converts normal maps to this format), on the other side I dont know why, normal map compressed by ATI2N has same size as ARGB texture in DTX5 and there is performance drawback in case of non ATI HW. So I dont see much added value here.
werner.poetzelberger Posted September 6, 2013 Author Posted September 6, 2013 Right. So I will keep it in RGB8. Have to be careful about resolution, as buig NM do cost a lot of performance. Cheers Werner
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