Re: Alphablending

Source and destination refers to background and foregound image
in the docs I read.

You could call them that, it doesn't really matter. Basicly it is a
state machine with two input ports and out output port (two images come
in, one comes out).

The two that are blended into each other producing a 3rd image.
They are not some "concepts" from DirectX or OpenGL.

I have been explaining the Alpha Blending in the context of OpenGL and
Direct3D, there the other input port, so to speak, happens to be the
output port.

In otherwords, the framebuffer is called "destination" and incoming
fragment is called "source", we don't even have to have texture mapping
enabled.. it could just be a flat color triangle, or gouraud shaded
triangle.

In my application's context, "source" is the sprite image and the
"destination" is the screen image. For the alpha blending engine, that
is being used in the application, the output port is not related to the
two input ports in any way, except that it *allows* the output to be
one of the inputs, because of strict ordering or reads and writes.

*phew*, but it seems that you got it nailed down already.. just
clarifying the different contexts at play.. there's always room for
interpretation because there is little bit of lacking in formal
definitions, these are as far as I know of, de-facto standards agreed
by different sentients practising similiar activities. <g>

.