Support for high resolution?

[L1uTongwei]

look these codes in video_gen.cpp:

//selects the widest render method that fits in 46us
//as of 9/16/10 rendermode 3 will not work for resolutions lower than
//192(display.hres lower than 24)
unsigned char rmethod = (_TIME_ACTIVE*_CYCLES_PER_US)/(display.hres*8);
switch(rmethod) {
case 6:
	render_line = &render_line6c;
	break;
case 5:
	render_line = &render_line5c;
	break;
case 4:
	render_line = &render_line4c;
	break;
case 3:
	render_line = &render_line3c;
	break;
default:
	if (rmethod > 6)
		render_line = &render_line6c;
	else
		render_line = &render_line3c;
}

It seems that the cycles would make effort to render mode.
Now I have 16Mhz ATmega328P, what is the max resolution? (If we don't care memory...)
Do 640x480 even 1024x768 possible?

[L1uTongwei]

Then, in order to read information of line, I edit render functions:

for(int16_t i = 0; i < display.hres; i++){
    display.screenBuffer[i] = display.screen[renderLine * (uint32_t)display.vres + i];
}
//......

Would it change the feature?