lets assume an alpha of 1 means fully opaque and 0 means fully transparent. lets say i have two black images which have 50% transparency (alpha = 0.5).
if they are laid on top of each other, the resulting transparency is 0.75, right?
if they would have an alpha of 0.25 , the result would be around 0.5, right?
if they would have an alpha of 0.9 , the result would be around 0.97, right?
how can you get to these numbers?
in other words i am looking for a function that gets the resulting alpha value from two other alpha value.
float alpha = f(float alphaBelow, float alphaAbove)
{
//TODO implement
}
This answer is mathematically the same as Jason's answer, but this is the actual formula as you'll find it in reference material.
float blend(float alphaBelow, float alphaAbove)
{
return alphaBelow + (1.0 - alphaBelow) * alphaAbove;
}
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