Skip to content
View in the app

A better way to browse. Learn more.

The AVSIM Community

A full-screen app on your home screen with push notifications, badges and more.

To install this app on iOS and iPadOS
  1. Tap the Share icon in Safari
  2. Scroll the menu and tap Add to Home Screen.
  3. Tap Add in the top-right corner.
To install this app on Android
  1. Tap the 3-dot menu (⋮) in the top-right corner of the browser.
  2. Tap Add to Home screen or Install app.
  3. Confirm by tapping Install.

DXT1 - Lack in image quality after converting?

Featured Replies

Hello Guys,I'm just creating some large scaled textures of 1024x1024pix size. When I use PhotoImpact for converting them from 24bit to 8-bit, all works very well and there is no real difference visible.But when I use ImageTool to convert the same texture (doesn't matter if from 24-bot or 8-bit) to DXT1, there is a real lack in quality.Is is not possible to get the same result with DXT1 as with 8-bit BMP? Or are there any hints and tricks to get better results?Best regards,Sasa

  • Author
  • Commercial Member

Hi Sasa,I have never seen a big difference after converting to DXT1 (DXT1 is 16 bit, so converting to 8bit first is not really useful). What do you mean with a low quality? Does the image look blurred or so? In that case it could also be that the highest mipmap is not shown on time.

Arno

If the world should blow itself up, the last audible voice would be that of an expert saying it can't be done.

FSDeveloper.com | Former Microsoft FS MVP | Blog

Hi Arno,Well, 8bit looks definetely better than DXT1 converted from 24bit. Just have a look at the Attachement above.I've never seen it that much before, but the bitmap converted there is quite large and has many colours in the grey range.Sascha

Hi,I use convr8 program for converting 24 bit to 8 bit.I red that DXT1 is rather for simple things. And that DXT3 gives more detail. Right ?Greetz. Jos

Hello Sascha,In order to see the best quality display of textures, it is necessary to place FS settings to the maximum.Please go to Options - Display - Hardware tab, and put the Mipmap slider to maximum (8).Best regards.Luis

do.png Hot, humid Caribbean paradise!

>In order to see the best quality display of textures, it is necessary >to place FS settings to the maximum.That won't help. The reduced image quality is already visible in ImageTool after converting.>I use convr8 program for converting 24 bit to 8 bit.R8? Isn't that FS5-style with 256 fixed colours?! ;)>I red that DXT1 is rather for simple things. And that DXT3 gives more >detail. Right ?DXT3 gives more detail for partly opaque/transparent parts of the image. But it doen't help to get better quality with it for all I know.Best regards,Sascha

  • Author
  • Commercial Member

Hi Luis,>Please go to Options - Display - Hardware tab, and put the>Mipmap slider to maximum (8).I don't think this option does that much. I have set it to 5 or 6 in general, when you set it to 8 the terrain texture don't look nice anymore, because the highest mips are shown too far away (gives a bit of a blinking view).But on the same settings page there is also an option for the texture size (at the bottom). Setting that to massive is necesairy to see the 1024x1024 mip of any texture.Sasa, do you also have mipmaps in your 8bit image? I am thinking it could be a wrong texture scale in your GMax object. Causing the wrong mipmap to be displayed.

Arno

If the world should blow itself up, the last audible voice would be that of an expert saying it can't be done.

FSDeveloper.com | Former Microsoft FS MVP | Blog

  • Author
  • Commercial Member

Hi Jose,>I use convr8 program for converting 24 bit to 8 bit.>I red that DXT1 is rather for simple things. And that DXT3>gives more detail. Right ?No, the only difference between DXT1 and DXT3 is the size of the alpha channel. With DXT1 you can only have black and white in the alpha channel (so only fully transparant or not), while DXT3 allows you to use grayscales as well, so that you can have more levels of transparancy.

Arno

If the world should blow itself up, the last audible voice would be that of an expert saying it can't be done.

FSDeveloper.com | Former Microsoft FS MVP | Blog

Hello Arno,Please notice the trees in the images. This is with Mipmaps set to 4:http://forums.avsim.net/user_files/117336.jpgAnd here is the same view with Mipmaps to the maximum, 8:http://forums.avsim.net/user_files/117337.jpgAs you can see, the difference is quite noticeable. The virtual cockpit is also using DXT-compressed textures, as well as the gauges, and here also you can see a lot of difference in the quality.Best regards.Luis

do.png Hot, humid Caribbean paradise!
  • Author
  • Commercial Member

Hi Luis,That shows quite some difference indeed. But don't you find that the landscape looks to "noisy" when you fly around with this mipmap setting? Or maybe that is a personal taste as well.I guess when you get closer with the mipmap setting at a lower value, the more details mip will still show? It is just the time at which it shows that differs I guess.

Arno

If the world should blow itself up, the last audible voice would be that of an expert saying it can't be done.

FSDeveloper.com | Former Microsoft FS MVP | Blog

>Sasa, do you also have mipmaps in your 8bit image? I am thinking it >could be a wrong texture scale in your GMax object. Causing the wrong >mipmap to be displayed.It doesn't matter if I use mipmaps or not. After converting there is a real difference visible. If you like, I will send you the sample image (approx. 2-3MB, 24bit) by mail.Sascha

  • Author
  • Commercial Member

Hi Sascha,Sure, I am certainly interested to take a look at it.

Arno

If the world should blow itself up, the last audible voice would be that of an expert saying it can't be done.

FSDeveloper.com | Former Microsoft FS MVP | Blog

  • Author
  • Commercial Member

Hi Sascha,I took a look at the texture and there is indeed a small difference in the quality of the textures. This must be due to the compression that is added to the DXT texture.But I also made two test cubes in GMax and placed the two textures on them (one 16 bit (555) and one DXT1 texture). And I must say that you hardly see the problem in that case. Only when you are really close (witin a few meters or so) I find the difference really noticeable. And I guess when you don't know the difference, you would not even find the DXT texture looking bad.

Arno

If the world should blow itself up, the last audible voice would be that of an expert saying it can't be done.

FSDeveloper.com | Former Microsoft FS MVP | Blog

Thanks Arno! :)Well, when you're 100 meters away from the object you may not notice it. But these object is a hangar und usually you would get close to it.So on the one hand you have to option to get worse results with DXT1 and save around 30% of texture size. On the other hand you can get the best results with 30% more texture size.I guess with the new computer systems that won't make a big difference anymore.Sascha

Create an account or sign in to comment

Account

Navigation

Search

Search

Configure browser push notifications

Chrome (Android)
  1. Tap the lock icon next to the address bar.
  2. Tap Permissions → Notifications.
  3. Adjust your preference.
Chrome (Desktop)
  1. Click the padlock icon in the address bar.
  2. Select Site settings.
  3. Find Notifications and adjust your preference.