• Advertisement
Sign in to follow this  

Compressed Texture Translucency

This topic is 3643 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

Anyone have a method to determine if a compressed texture (DXT1/DXT3/DXT5) is translucent? Checking if it has an alpha component does not necessarily mean it's translucent.

Share this post


Link to post
Share on other sites
Advertisement
Obviously this information isn't encoded in the texture but in a separate asset, such as the material descriptor. Id tech for example use the keywork BlendFunc (if memory serves), if no blend is specified then the alpha component is discarded... the texture itself knows nothing about blend, the alpha could be a gloss map as well.

Share this post


Link to post
Share on other sites
I agree. However, if the alpha is 255 for the dxt5, then we can assume that no blend operations are going to be used on that texture (???)

Share this post


Link to post
Share on other sites
Yes, if all pixels have alpha=255 then the alpha channel is redundant since the HW will fetch 1.0 for those pixels automatically.
It's a rather weird case. Theorically this shouldn't happen in the first place.

This doesn't magically imply blend won't take place - alpha could be injected by other means, such as a per-vertex RGBA color.

Share this post


Link to post
Share on other sites
Blending doesn't necessarily rely on an alpha channel being present or not.

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Advertisement