I notice in 4.4/4.5 we had some additional texture sampler types, Linear Grayscale and Linear Colour.
Whenever I use a Grayscale texture and sampler, with SRGB checked, I get a warning (particularly when making Instances of that material) that I should have SRGB unchecked for Grayscale textures. While it doesn’t stop the material from compiling, it does spit out a few yellow warnings in the instance.
I then go and uncheck SRGB, and change my sampler type to Linear Grayscale, but I then get outputted very different results due to the curve changes of the texture.
I’m not sure if it’s intended behaviour to get a warning whenever i use a Grayscale texture, or am I doing something wrong?
This is normal behavior. Unless you have made your texture in Photoshop without AA ,as a math style texture expression, and as a grayscale image you will want to keep sRGB turned on and the texture set to TC_Default as the compression setting. If you have a Grayscale image without sRGB checked and set to TC_Grayscale then the texture should be recognized as a Linear Grayscale as Sampler Type and will be treated as a texture that has no AA built in and used more for math expressions in the Material Editor. TC_Default and no sRGB checked would be Linear Color or a texture with color but no AA has been built into the texture.
They textures that you are importing in are they set to Grayscale mode in Photoshop or other photo editing program or are they still RGB 8 bit and just only using grayscale colors of variation of black and white?
Does that mean that the TC_Grayscale compression setting is not used anymore in that case? I’ve always used Grayscale previously for white & dark textures as it has less compression artefacts than TC_Default, so I get a better-looking grayscale image.
My bug report was that If I import the image and use TC_Grayscale, it doesn’t matter if the sRGB checkbox is on or off, I am told that i should use Linear Grayscale by the editor.
Ahh I understand, I was exporting them from Photoshop as RGB! So if I Import them as 8-bit Grayscale, I can use Grayscale WITHOUT sRGB checked to get the same result as before?
This is definitely a bug I think. I have now exported my texture from Photoshop as an 8-Bit grayscale image. I have imported it and set the compression to TC_Grayscale.
When I use it in a material it doesn’t report any error, however when I make a material instance, the Material Instance Editor tells me that I need to have sRGB unchecked. As soon as I uncheck sRGB, The Material Editor and Instance editor tells me that it has to be a Linear Grayscale sampler.
What this means is that it’s currently not possible to use TC_Grayscale or the Grayscale sampler properly.
I have only been able to reproduce this error when placing a Non-Greyscale texture into the parameter slot where the original linear greyscale texture was located.
Here is the exact error message that I received and only after changing the texture parameter:
