Tips on accelerating the YUV conversion...

[Brendan Robert]

At the cost of memory usage (this is really negligible though) you should consider using a multi-dimension array and pre-calculate the conversions of these math operations:

						data[c]   = (int) Math.min((data[c] & 0xff0000) * 1.30f, 0xff0000) & 0xff0000;
						data[c+1] = (int) Math.min((data[c+1] & 0xff00) * 1.30f, 0xff00) & 0xff00;
						data[c+2] = (int) Math.min((data[c+2] & 0xff) * 1.35f, 0xff);

That way you can use lookups for integer values rather than more expensive on-the-fly float operations.  I saw a tremendous speedup in my Jace emulator when I implemented this.  Here's my take on it, as well as the necessary YUV conversions, starting around line 196:

https://sourceforge.net/p/java-ace/code/285/tree/jace/src/jace/apple2e/VideoNTSC.java

The Apple // display is of course very different than Atari.  It only had a fixed palette of 16 colors so I was able to represent just those 16 colors.  But you can see how I am able to convert each pixel to RGB more quickly on the fly using this lookup technique.

I am very impressed how you implemented other features!  Great work!

-Brendan

[Paulo Peccin]

Yes, it can be a good point for optimization! Thanks for the tip!

I did not invest much time in this yet, since its used only when you activate a special "CRT" mode to emulate the RGB triads. This code is not used during normal emulation.

But you're right. 

The 2600 has a 128 color palette, so I will need bigger arrays with pre-calculated values for PAL and NTSC, but not too big of a deal.

Regards,

Peccin