Fading/Scale over time..

[Roose Bolton of the Dreadfort]

Okay I am trying to make an object fade over a certain time;

so say I want it to fade over 1 second, if I want to find out how much to remove each frame, whats the algorithm for it?

Alpha is 255 so say I want it to fade over 1 second I can do 1/255 to give me how much to subtract.. but my framerate is set to 60.. so only 60 frames are called a second not 255..

Cheers guys.

[Nexus]

There is no "algorithm", it's simply division. You compute the ratio of the fading's progress in [0,1], and multiply it with 255.

By the way, if you don't want to reinvent the wheel, I have already implemented thor::FadeAnimation which can be applied to any class with setColor() and getColor() methods.

[Roose Bolton of the Dreadfort]

Cheers Nexus.

so;

mSubtract = mLifeTime/255;

.....

loop{

mAlpha -= mLifeSubtract * 255;

}

 

Thats what your saying yeah? But there is only 60 frames in a second.. so this will only be called 60 times meaning it wont get all the way.. I am missing something

[FRex]

Maybe:

m_Alpha=255-255*(nowtime-starttime)/(endtime-starttime);

Be careful to avoid pitfalls of integer division.