Yea and now make one with opengl and you should see the difference.

Also you should to go into full screen mode. Much easier to see the difference.

Same as other shot, only with output=opengl. See any difference? There actually is a little bit, if you do a "difference" of the two images in Paint Shop, you'll see small differences in the blending.

If you don't see the vertical blending of pixels going on in these shots, you need to look closer, or blow them up with a viewer.

Can't see a difference in your shots at all...

You didn't go fullscreen yet, did you?

Here two fullscreen pics:

Save them to the desktop, open it as fullscreen and use the arrow keys to toggle between them. The difference should be very visible.

I can't take a screenshot in ddraw as fraps doesn't work with this, but it looks identical to openglnb.

The point I made was not about what output looks more blurry than another. I said that blending of pixels will occur with aspect correction unless you use output=openglnb. Look at both of my shots, they both show the pixel blending.

Well bilinear filtering manifests itself in a blurry image. You can call it whatever you like.

Take a look at the screenshots above and if what you see is "pixel blending" in your eyes, then we are talking about the same thing.

Please go fullscreen and you will see that ddraw is clear, whereas opengl is still blurry...

Maybe the difference is that I use fullscreen exclusivity whereas you are using window mode and there could be differences.

But if you go fullscreen I guarantee you that ddraw, openglnb and overlay are clear and opengl is the only one that is blurry.

What does how fullscreen appears with either ddraw or opengl make what I said about the blending of pixels not correct? Please stop changing the subject.

My screen shots contradict what you said.

So let's investigate the issue further and find out why this is the case...

Can you see the differences in the above screen shots (The ones showing the island). One is clean and the other one is blurry. Is this this the "pixel blending" you are talking about?

How do they contradict what I said?

And your screenshots are poor examples. Look at clean text on a plain background like the menu in my shots, the blending is very easy to see.

ripsaw8080 wrote:

How do they contradict what I said?

get some blending of pixels unless you use output=openglnb

Firstly it's "no bilinear" and not "no blending".

My screenshot with output=ddraw shows the difference to opengl. Something that contradicts with your screenshots.

Now this isn't about right or wrong. In my screenshots there is a difference, in yours there isn't.

So let's work together and investigate why this is the case

And your screenshots are poor examples. Look at clean text on a plain background like the menu in my shots, the blending is very easy to see

Oh come one don't be like that. They are fine and show the difference.

Did you see a difference or not?

Also you didn't provide a openglnb image yet. Maybe this will help us move the discussion forward.

If you're using aspect correction (aspect=true), you will get some blending of pixels unless you use output=openglnb ("nb"=no blending), and that is regardless of what scaler you use.

I've repeated my statment that you said was not correct, because you seem to have forgotten. Your opengl shot shows blending of pixels just as mine do, although it's much easier to see in mine. So, you've supported my statement, not contradicted it.

Ok I'm getting somewhere now...

There is a difference depending on if you are in window mode or in fullscreen mode.

I did 3 screenshots in window mode and they confirm your findings. The first two are blurry, the final one (openglnb) are clear.

Overlay:

Ddraw:

Opengl:

Openglnb:

Now I need to find a method to do a fullscreen screenshot in ddraw mode!

Have you got any ideas?

Because when I'm in ddraw mode and I go fullscreen (ALT+ENTER), the image suddenly becomes clear, just like with openglnb.

Whereas if you are in opengl mode, the image stays blurry when you go into fullscreen mode.

Or just try to replicate this yourself. Just toggle between window and fullscreen mode in ddraw and opengl mode and you should also notice that opengl stays blurry, but ddraw becomes clear when in fullscreen mode.

Maybe my use of the word "blending" is confusing to someone that isn't me.

With openglnb and aspect correction, you will get perfectly "blocky" pixels with clean, distinct edges; but they are usually of irregular size (a kind of distortion in its own right).

With ddraw, overlay, and opengl, you will get "bilinear filtered" edges, what I call "blending" between neighbor pixels. Blowing the images up in fullscreen just makes it less obvious because the edges of the pixel blocks are relatively smaller.

There is one way you can get aspect correction and perfectly blocky pixels of consistent shape, but official DOSBox does not support it. Namely, this is the ability to do scaling of any integral in both height and width. Take for example the common 320x200 screen. The correct aspect is 1.2, or pixels that are 20% taller than they are wide. If you scale 320 by a factor of 5, and 200 by a factor of 6, you get 1600x1200. With this kind of scaling you'd have perfectly blocky pixels of regular size and shape with correct aspect.

PrtScrn worked for ddraw mode and for opengl I used fraps.

Fullscreen with ddraw:

Fullscreen with opengl:

So there we go, different outcomes depending on window or fullscreen mode.

Let's summarize it:

Windows mode:

Overlay: Clear (so it appears that openglnb isn't the only mode that doesn't blend, even when only considering window mode 😉 )
Ddraw: Blurry
Opengl: Blurry
Openglnb: Clear

Fullscreen mode:

Overlay: Clear
Ddraw: Clear
Opengl: Blurry
Openglnb: Clear

So in essence, we where both right, however we where unaware that the behaviour is somewhat different depending on if you are in window or fullscreen mode.

However openglnb seems to be the better choice, as it gives you a clear image in both modes!

Well that was a productive session, I learned something new, hope you feel similar...

ripsaw8080 wrote:

Blowing the images up in fullscreen just makes it less obvious because the edges of the pixel blocks are relatively smaller

No, please read my post carefully. The images aren't "blown up". They are in fullscreen mode (Hit ALT+ENTER).

Fullscreen mode does blow them up, though. How else do you think a 320x200 image scaled to 640x400 with a normal2x scaler becomes as large as your display?

Here is a part of your ddraw screenshot blown up in Paint Shop to 16x. You can clearly see that the pixel blocks are of irregular height. If you really are using ddraw, then your ddraw behaves like openglnb at higher resolutions. Because when I use ddraw at fullscreen, I still get filtered edges; but the edges are so small that it's harder to notice the filtering.

Yea that shot was with ddraw.

There might be other factors we arent aware off. I'm using ATI onboard graphics and W7, so there might be differences depending on what hardware and software one uses.

I know there are distinct differences due to graphics drivers, that is nothing new. First time I've heard of a case where ddraw behaves like openglnb in fullscreen, though. Maybe we can conduct a poll to see which is the more common behavior (blocky or filtered in fullscreen ) amongst other users of DOSBox. 😉

aspect=true uses hardware scaling. That can be blurry with outputs which have bilinear scaling by default (ddraw, overlay, opengl (without nb). The same with fullscreen mode, but that depends on the fullresolution as well. If set to original, there will be no scaling except by the LCD.
Direct3D can do integral scaling 😀

Yea it's quite interesting...

I will just settle for openglnb and recommend it from now on.

It's result seems to be consistent and it doesn't throw Aero when you toggle between window and full screen which is nice...