Bmp sprite alpha blending...

[Sylus101]

Hey again,

I can't seem to get alpha blending to work with a bmp sprite. Using the bmp sprite example and changing the palette-alpha value to 5 instead of 15 for the bmp sprite, the sprite is not blended at all. Anything obvious I might be missing? I've tried enabling alpha blending in the blend control register but I'm not sure I'm doing that correctly or if that's necessary for this type of blending.

Thanks everyone,
Sylus

EDIT - 7/15

Okay, I wanted to come back and update this post a bit. I studied the gbatek spec sheet a bit more and was able to more or less figure out how alpha blending works, both globally (just using the blend control register and blend alpha register) as well as setting a 256 color sprite's mode to blending and setting the 2nd target in the blend control register. This has solved my problem, so I'm able to continue what I was doing, but I still had trouble understanding how to get this to work with bmp sprites. The palette setting, as I'm reading it, should set the alpha blending value... what I'm not sure is if this is supposed to replace the 1st coefficient value or what exactly. From testing, I had to have bit 4 set in the blend control register (1st target objects) for the bmp sprite to blend at all and modifying the palette value in any case seemed to do nothing. What am I not understanding?