Anti-aliasing/Interpolation filter/smoothing effect for lo-r

adventur · Post by **adventur** » Mon Feb 20, 2006 9:52 pm

Hi, I have ben using & tweaking ScummVM the best I could with the help of a couple faqs, and I have the following question, is there a way to get a graphical filter that would do some smoothing effect that enhances the graphics without deforming it or anything (it's just a slight blur that gives the effect of older low-res monitors) it's pretty common in other emulators, and I really like that effect, is there any way to give similar effects? the available filters are sadly not quite what I am looking for.

Kaminari · Post by **Kaminari** » Mon Feb 20, 2006 10:13 pm

If you're looking for a horizontally-interpolated TV mode, there's none (a feature request exists on SourceForge though).

adventur · Post by **adventur** » Mon Feb 20, 2006 11:50 pm

not necessarely tv mode with the scanlines, just plain Interpolation, as it is called in the Zsnes emulator, the thing is, as soon as you enlarge the window it gets smoothed most of the time in most emulators like Mame and the rest. Such is not the case with ScummVM, not that I know of yet, I wish there were some way to, because I find it makes a nice visual enhancement to the classic 320x200 graphics.

domino · Post by **domino** » Tue Feb 21, 2006 12:25 am

i think you mean just simple hardware stretch and i co sing under this idea too

that would be very nice to give users choice between hardware stretch and these other already available filters

adventur · Post by **adventur** » Tue Feb 21, 2006 3:59 am

Yes, actually most emulators have a free-zooming window that does the hardware-stretch you are right, plus additional filters wich is very pleasurable for the eye in my opinion. I personally like sometimes tv mode but what I above all prefer is the pixel-smoothing sensation.

LogicDeLuxe · Post by **LogicDeLuxe** » Tue Feb 21, 2006 10:55 pm

It was there at some point in ScummVM history, at least, I can remember having it working in full screen mode (not that I really needed it). I don't know why it was dropped. Maybe code size or compile time?

fingolfin · Post by **fingolfin** » Wed Feb 22, 2006 9:13 am

adventur wrote:not necessarely tv mode with the scanlines, just plain Interpolation, as it is called in the Zsnes emulator, the thing is, as soon as you enlarge the window it gets smoothed most of the time in most emulators like Mame and the rest. Such is not the case with ScummVM, not that I know of yet, I wish there were some way to, because I find it makes a nice visual enhancement to the classic 320x200 graphics.

But you do know that ScummVM already includes several graphics filters, including Advmame2x/3x (coming from MAME), hq2x/hq3, SuperSAI etc., don't you?

From what you say, it's not fully clear to me that you are aware...

Kaminari · Post by **Kaminari** » Wed Feb 22, 2006 2:39 pm

I think Adventur is after "good" old bilinear filtering ;)

adventur · Post by **adventur** » Thu Feb 23, 2006 7:30 pm

Yes, of course I know, I have tried all of these and I never liked them, I think they just deform the original graphics a bit too much for my visual tastes, the only filter I mainly use is "Hardware stretch" just to fade those pixels a little bit, altough I think bilinear filtering does something similar.

domino · Post by **domino** » Fri Feb 24, 2006 12:05 am

i can also say that these filters always change graphics less or more but hardware stretch keeps original graphics and that is the one of the reasons why it is better (for me)

another thing is that i can stretch picture to ANY aspect ratio which cant be done with these filters..

hardware stretch is also much faster than anything else which is important for slow pcs...

i remember old versions had opengl output with bilinear filtering and it looked great and much better than filters

some time ago there was discussion about hardware output and someone said that its very easy to implement it.. so do you developer guys consider to add that option to scummvm? im not saying that these filters are completely bad or something, im just saying that some people prefer bilinear filtering and some people prefer filters so that could be nice to give us option which one we want to use

i hope you understand it and hopefully someone of you will add this option so everybody could be happy

adventur · Post by **adventur** » Fri Feb 24, 2006 12:19 am

Yes! exactly that's it I remember the Opengl was there in early ScummVM builds, that's why I was confused when toggling between filters in the latest builds, since I couldn't find it, I tried the others, but they don't feel quite right, that's why I use Dosbox.

Post by **eriktorbjorn** » Fri Feb 24, 2006 3:03 am

domino wrote:hardware stretch is also much faster than anything else which is important for slow pcs...

Depends on how well that hardware is supported. Right now, OpenGL is completely unaccelerated on my computer, so I can say for certain that ScummVM's old OpenGL renderer is utterly useless for me at the moment.

domino wrote:i remember old versions had opengl output with bilinear filtering and it looked great and much better than filters

I'm not sure there ever was a stable release where the OpenGL backend looked good for me. For one thing, I found it eye-strainingly blurry, and for another there was an ugly vertical line running down the right side of the image, like this:

This image was made with ScummVM 0.5.1. The vertical line bug may have been fixed in the development version at some point, though, I don't remember. As far as I can see, the OpenGL renderer had been removed by the time 0.6.0 was released.

domino · Post by **domino** » Fri Feb 24, 2006 9:36 am

to be honest i dont remember this vertical line bug, but even if it was there i bet you could fix it

as for the opengl acceleration - my pc support it very well, your not and thats the whole point - some people prefer opengl, some poeple not

as you can see every pc is different and everyone has different needs - thats why i think there should be a choice between harware output and filters

we live in democracy world, right?

fingolfin · Post by **fingolfin** » Fri Feb 24, 2006 11:51 am

domino wrote:to be honest i dont remember this vertical line bug, but even if it was there i bet you could fix it

as for the opengl acceleration - my pc support it very well, your not and thats the whole point - some people prefer opengl, some poeple not

as you can see every pc is different and everyone has different needs - thats why i think there should be a choice between harware output and filters

we live in democracy world, right?

No, not all. Most parts of this planet are not governed by any kind of "democracy", I am afraid.

In particular, ScummVM is neither governed nor a democracy. If you like a feature, supply a patch that adds it and we *might* add it. Or not. If you can't code, maybe you are lucky and manage to convince somebody who can to implement that feature for you. If you aren't lucky, well... that's life

.

So, yes, *maybe* "we" can fix that bug -- but the main reason we threw away the OpenGL scaler back then was that it was (1) full of bugs, (2) most people found it dead ugly (yes, there were exceptions, like you are one), and, (3) ultimately the most important thing, nobody was interested in maintaining it, so it was just rotting.

Hence we decided to throw it away, and so far haven't regreted that in any way

. And as it is, we have many other things on our TODO list that we consider far more important than re-adding an OpenGL based bilinear scaler (or a software based bilinear scaler, for that matter -- it would take me an hour to implement and test one, but I simply don't see the point).

Post by **sev** » Fri Feb 24, 2006 12:22 pm

domino wrote: we live in democracy world, right?

Well, no democracy in the world will let you force somebody to do something for you. That thing is called somewhat different: a slavery. I.e. I want it, you do it for me now.

So you still may use your democracy and create a fork of ScummVM, or use abovementioned approaches which Fingolfin suggested. Our license allows that.

Eugene