I'm working at a larger projekt in which  i make use of off-screen graphic buffers (of type PGraphics).

But there is a problem when I want to blend one ('g') to another ('graphics') with transparancy (changed by factor 'afcator')

1.     g.loadPixels();
2.     for (int i=0; i<g.pixels.length; i++) {
3.       int c=g.pixels[i];
4.       g.pixels[i]=color(red(c), green(c), blue(c), (int)Math.round(alpha(c)*afactor));
5.     }
7.    graphics.blend(g,0,0,g.width,g.height,0,0,graphics.width,graphics.height,ADD);

Since this was much to slow I tried to work with tint.

1. tint(255,(int)Math.round(afactor*255));
2. image(g,0,0);

This one would work, but since I need to write the output to graphics and not to the screen this is also no option for me. So this is what I tried next:

1. graphics.tint(255,(int)Math.round(afactor*255));
2. graphics.image(g,0,0);

And this finally got me a NullPointerException. I really don't understand where that came from, especially since it is not really different from the example before.

So if anybody knows what went wrong,  I really dont konw what to do next.