Software DDS file Sizes

[paddy2]

I have made a texture in fireworks as a .PNG
This is then saved as a .BMP
Passed to DxTex to convert to a .DDS

works fines looks nice etc. etc.

DDS file size is 1Meg
open in Paint.net and save it and the file size is down to around 128k !!!

So a 1meg files becomes a 128k !!!

That file in turn is loaded into Orbiter and displayed. Will it use 128k of video Ram or 1M? i.e. while the smaller file and its 10- 15 friends will give a smaller package to down load is it just a waste of time/processing as far as the video card is concerned?

My question then is, whats the benefit to saving/converting via paint.net over the supplied DxTex.exe.

Thanks in advance Gents

 

[Loru]

DDS file can compress image in many different ways. Depending on compression level an included or not mipmaps filesize may vary a lot.
With compressed textures you may lost some small details but usually it's not an issue.

As for how much it'll take in VRAM - that depends on GPU/drivers and fact is texture is "dynamic" (used for example as instrument display).

 

[orb]

DDS file size is 1Meg
open in Paint.net and save it and the file size is down to around 128k !!!

Looks like you haven't chosen the compression format before saving it in the DxTex. 128 * 8 = 1024, and for example DXT1 with no alpha compression ratio is 8:1.

That file in turn is loaded into Orbiter and displayed. Will it use 128k of video Ram or 1M? i.e. while the smaller file and its 10- 15 friends will give a smaller package to down load is it just a waste of time/processing as far as the video card is concerned?

My question then is, whats the benefit to saving/converting via paint.net over the supplied DxTex.exe.

Paint.net most likely have chosen the most appropriate DXT algorithm when you saved it as DDS by checking if there's alpha channel in your image, while in DxTex you need to choose the most appropriate format by yourself.

The texture will use 128k of VRAM if it was compressed with DXT1 and doesn't need to be uncompressed for processing. If it needs processing, it will use 1M of VRAM, like its uncompressed version.

There's no real benefit using one or another converter. You can say that DxTex can only open BMP and doesn't display the image, but it isn't true. There is a newer version of DxTex included with DirectX SDK, which also handles PNG, TGA, JPG just fine (with alpha channel included), and additionally displays the image being opened and shows how it looks after the format conversion.

 

[paddy2]

So would I be right to say then,

Save textures via Paint.net for the compression, if they have to be processed then it will happen in any case!

 

[orb]

So would I be right to say then,

Save textures via Paint.net for the compression!

No. Rather: "Save textures with any program supporting them, but don't forget to choose appropriate compression algorithm".

 

[paddy2]

Ok thanks

Bye the way I downloaded the SDK for the new DxTex and for anyone reading this thread it does show the texture, nice for peace of mind