Slick Forums

I tried to set alpha for spritesheets, but it doesn't seem to have any effect, example below:



I guess this is the intended effect, right?
Or I am doing something wrong?
Is there a possibility to change the alpha for a whole SpriteSheet?

Yeah, it's a bug. SpriteSheet extends Image, which IMO is kinda poor design, but some things were forgotten like setAlpha, setRotation, etc. Added it to the TODO list...

Since each sprite in a sheet is its own Image class, you can apply individual alphas to each via getSubImage(cx, cy).setAlpha. However, I'd recommend learning to apply alpha manually, as setAlpha may become deprecated in future versions of Slick.

thx!!!


interesting, why will setAlpha be axed?
I mean the filter feature is nice, but basically it is a bit "low-level".
Especially, I don't see how removing setAlpha is really related with one of the goals:


my current impression - I may be terribly wrong - on the documentation (e.g. why should we mention that angles are in radians, why would anyone in a 2D game library think about using so daily-lifely like degrees!?) and tutorial stuff is that the "library" has a kind of an elitist touch, which would be ok if it would be written in C or Assembler, well but it is Java but I guess that comes from the OpenGL background.

In short, it's poor design to put things like alpha/rotation/etc. in the Image class, which should primarily just be a container with sub-image coordinates and a center point. Alpha/rotation falls in the same category as x/y/width/height values, which should be implemented by the user in an Entity-like class. Just like you don't see Image.setX/Y, you also shouldn't see Image.setAlpha.

Furthermore, it creates conflict & ambiguity when tinting an image:


Removing it is just my opinion, though, and I'm sure some other devs/users will disagree. So it probably won't get axed, at least for a long time.

Unfortunately, when setRotation/setAlpha was added, it wasn't really considered fully. drawEmbedded, drawFlash, SpriteSheet.draw, copy(), etc. don't take it into account, even though they potentially should. So now it's a matter of tracking down the various areas that were overlooked and fixing the bugs. But the small dev team has other priorities...


Is this sarcasm? Lots of beginners might not know what "radians" even means...

thx a lot! I learned something, I like that!



YES, it is sarcasm:

http://slick.cokeandcode.com/javadoc/or ... html#angle

my first post on this forum was about this, but to this day it wasn't approved
now, the odd thing is, I found out that it is in radians, but now I found that:

http://slick.cokeandcode.com/javadoc/or ... 28float%29

but being normalized doesn't really imply that is in degree also?

or my memory that it was in radians is wrong or ???
well, back to the facts: the documentation is missing what kind of unit it is, which in my opinion is crucial.

that's a good point. I've spent a few hours myself figuring out why angles weren't working properly. I wonder if any of us developers has access to the documentation; that shouldn't be hard to change.

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