Hi,
I'm currently trying to convert the attached images to astc.
The settings I have specified is 4x4 and linear LDR for "alpha1.jpg". The tool displays each pixel's value as R = G = B with A = 255, so I specify "Other Options" swizzling before encoding G = 0, B = 0, and A = 0 because I only care about the R channel. Unfortunately, I get "Commandline argument '-esw r000' not recognized". If I remove the "Other Options", it works.....I also tried 4x4 SRGB LDR with Other Options turned off, but I get "Compression stopped"
None of the above configurations work for "alpha11.jpg". Both images work with the solo option of HDR......which doesn't sound right to me. Am I misunderstanding how to use the tool?
Thank you.
-esw r000 should be a valid command line argument, so my first guess would be that the user interface was sending several arguments and they don't work in the order it's chosen. A little check on my side shows that even a default swizzle (-esw rgba) is returning the same fault. I don't think you've used the tool wrong, one of the interesting aspects of the ASTC format is that any image can be compressed as though it were HDR or SRGB, it's just about how the colourspace is interpreted.
I'll see if I can find out why some arguments are hitting the command line wrong.
In the mean time it's worth noting that due to the way ASTC works, since the images are greyscale there is no compression advantage to an r000 swizzle, you should get exactly the same image quality by compressing it as is and then sampling red only in your shader.
-Stacy
If the output has only one useful channel anyway, is there a way to output a single channel luminance texture for this input?
Chris, the way ASTC works it makes no difference. Regardless of input format every ASTC output image is essentially RGBA.
gotcha.
Hi Stacy,
The astcenc.exe command line works
I'll use the GUI for testing only then.
I also encountered something odd: does the tool not support loading in ASTC files? The file format say whether the image is sRGB vs Linear, but maybe a prompt can be popped up to ask for options.
The tool is intended for compression, so there is little point in loading in ASTC files. Files can be decompressed in the command line, and you can even run in test mode, where a file is compressed and immediately decompressed by the command line tool, producing an image which contains the compressed result, but in a standard file format (such as PNG, which is lossless and therefore good for determining compression artifacts).