danorf wrote:- plot precise effect or x2, x4, ... (C2P ?)
danorf wrote:- real effect or mainly precalculated
Real effect. In the bottom of a chunky buffer, you add random noise. Then you run a smoothing pass with the smooth result written to the buffer a bit higher than the source.
I'm s h i t (have to write it with spaces or the darn forum writes "poo" instead!) at explaining highlevel, but something like this in 68000;
lea 160(a0),a3 ;that's one line beneath a0
You do this for each pixel in the chunky buffer, then you also need to c2p it to screen. The pixels chosen for average can be done differently for different result, for example doing +159, +160, +161 would perhaps look better. It's for experimentation.
danorf wrote:- in how many VBL it runs
That my friend is totally up to the level of optimization you can do. The above example with a c2p pass after will certainly not be very optimal, but easy to read.