Moving Images With Transparency

[TheAmplifier]

Hi, all...

I've recenetly started a project where I need an image whose background is transparent (using the BitBlt technique), on top of of a non-transparent image that will move up and down the screen.

Does anyone know a way to do this that is fast? I tried compositing the two images together and then drawing them to the form, but it's sooo slow (or either I wrote it really inefficient!).

If anyone has any ideas, I'd appreciate any help! I'm kinda still new at this stuff, so please go moderately slow.

- Amp

[Sastraxi]

If you need a basic-intermediate-advanced tutorial go to mine:
http://vbden.tripod.com/articles/invmask.htm

Use Bitmasks, where all white pixels are BG and all black pictures are drawn (like a silhouette), make sure the corresponding pixels in this that are white are black on the real sprite picture.

This will (hopefully) show you what you are looking for.

[TheAmplifier]

Ah, that explains it a lot clearer than what I've seen so far! Thanks so much!

Now, all that's left is figure out how to put another image that can move freely up and down the screen behind the newly made transparent picture and I'll be set.

- Amp

[Sastraxi]

That's easy; just change the blitting order. Blit the background first, then the thing that moves behind, then the normal sprite. PS. you can do only the first step of ANDing the mask to make a cool shadow...

[Sastraxi]

Oh! You mean just a background not another image, well, use SrcCopy constant, that will blit the rectangle of the bitmap (the whole sprite), the whole background.

[TheAmplifier]

Ah, thanks! It works great, and fast too! Thanks for your help!

- Amp

[Sastraxi]

No problem

[Arbiter]

Awwww Sas,

You're just everyones hero!

[TheAmplifier]

Mine at least.

[Sastraxi]

Ain't it the truth

So much attention