Internal vs External/Output Resolution

[Clockwork]

One thing I have have realized is although the emulator accurately renders using the 3DO's internal resolution of 320x240, it doesn't accurately mimic the output which was 640x480 using a unique interpolation system as outlined here:

http://www.google.com/patents/US5481275

Very interesting stuff.

Although the Smooth, Double Resolution Rendering, and HQx options are nice it doesn't quite match what the unit actually output to the screen.

Do you think there would be such a way to implement this? With the above in mind I don't really think we should be seeing a 320x240 output option.

[BryWI]

I never really looked at the source of what the double resolution rendering does (I probably wouldn't understand it anyways) but I thought that option was doing what the system did to get it to 640 x 480. If you look at 3d games like Starfighter, it really makes a difference. It does not make much difference on the 2D stuff though.

[Clockwork]

I'm not so sure that's the case, but I wouldn't mind being corrected if it was.

I just know the standard output of the 3DO looks better than the somewhat rough nearest-neighbor scaling (smooth scaling off) and fairly blurry bilinear interpolation (smooth scaling on) that is currently implemented.

As a side note, I think this emulator is fantastic.

[Johnny]

The 640x480 resolution you refer to is sometimes called "interpolation". One of the versions of FreeDO had this option. I can't say for certain if it works right. But, right now 4DO ignores the "interpolation" data. So, at the moment we're missing out on that detail for games that use it.

However, it wasn't exactly 640x480. What it really did was weight each pixel so that either one corner or one side of each pixel was brighter than the others, but not different in color. So each pixel became a 2x2 pixel block with one section brighter. This allegedly helped make fonts a bit more readable. I don't know that a lot of games used it, especially with the number of PC ports created. I would expect only 3DO exclusives used this feature. It was specific to 3DO hardware, after all.

It is feasible that someone could put time into the emulator to ensure that this processing gets implemented in full. It would probably need to be an option since it would increase the processing time per frame. I didn't put much of a priority on it myself since there were more glaring inaccuracies (like the palette problems in the Horde and Wing Commander III).