Interesting! Are you drawing the figure by hand (and the shader does only the "leaking") or have you encoded the "drawing", too? How do you achieve the effect?
I drew the figure by hand and the shader does all the rest.
Originally Posted By: HeelX
I guess you use a "spray paint" brush bitmap which is written additively into an accumulating floating point target. You then use another target which is the target for the shader and you just push the values above a threshold x down in Y-direction, in an infinite ping-pong manner.
good eye! Yes, it is a brush bitmap rotated randomly each frame. The painting action is done over a floating point 32bit bitmap, as you guessed. The shader adds the brush values over it and glides down the overpaint. Everything is done in the same pass. I added a random left-center-right glide to achieve a saw teeth effect. I use an other shader to translate the previous bitmap to a colored and visible bitmap.
Here is the code, but remember that it is not a final version, just a workaround and not very fast indeed. enjoy!
