Hi guys,
does anybody know where I can find an example of 2d clouds like this:
or a shadow like this:
or like this:
I think it’s an effect made by the alpha channel
tnx
Hi guys,
does anybody know where I can find an example of 2d clouds like
this:
Some form of source alpha blending, most probably using a single “full
surface alpha”.
You can do this by using a color keyed source surface without an alpha
channel, and setting the full surface alpha value with
SDL_SetSurfaceAlpha(). This allows you to change the alpha (opacity)
without modifying the source image.
Alternatively, use a source image with an alpha channel, and enable
source alpha blending (ie per pixel alpha control by the alpha
channel of the image) with SDL_SetSurfaceAlpha(). This allows you to
vary the transparency to make thicker parts of the clouds actually
look more dense, than rather just brighter. It also has the bonus of
supporting antialiazing for smooth egdes around the clouds.
or a shadow like this:
Same thing, as above; just use a black mask image instead of clouds.
You can still chose between colorkey + full surface alpha and source
alpha channel, depending on your needs. (Real time alpha control vs
per pixel alpha and/or antialiazing, that is.)
or like this:
Looks like the cards are colorkeyed for transparency around the cards,
and then displayed as an alpha blended layer over the opaque cloudy
sky layer.
The text is either hardware sprites or a full screen colorkeyed layer.
In SDL, you’d implement it using either colorkey or an alpha channel
to control transparency per pixel. Again, the latter would allow
antialiazing and partial transparency effects.
I think it’s an effect made by the alpha channel
Yep.
(I think per-layer alpha is the only type of blending implemented in
the SNES hardware - which would explain why it is sometimes abused in
cases where per pixel blending and/or other types of blending would
have been more appropriate.)
//David Olofson - Programmer, Composer, Open Source Advocate
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