Working with JPEG format, but not jpg file...

[Samishii23]

A project I am working on has me thinking of going two ways, 1) Use own "In House" images with come with the end product, or 2) Using a proprietary image format from the producers of the program my project is based on.

The image format is a RGBA image format. Though I have heard of it based off of JPEG libraries.

This is the header struct:

struct BLP2Header
{
    FourCC      ID; // Always 'BLP2'
    UInt32      Type;
    UInt8       Encoding;
    UInt8       AlphaDepth;
    UInt8       AlphaEncoding;
    UInt8       HasMips;
    UInt32      Width;
    UInt32      Height;+7
    UInt32      Offsets[16];
    UInt32      Lengths[16];
    ARGBColor8  Palette[256];
};

Type
    0: JPEG compression
    1: Uncompressed or DirectX compression

Encoding
    1: Uncompressed
    2: DirectX compression

AlphaDepth
    0: No alpha channel
    1: 1 bit alpha
    4: 4 bit alpha (DXT3 only)
    8: 8 bit alpha

AlphaEncoding
    0: DXT1 alpha (0 or 1 bit alpha)
    1: DXT2/3 alpha (4 bit alpha)
    7: DXT4/5 alpha (interpolated alpha)

HasMips
    0: No mip levels
    1: Mip levels present (the number of levels is determined by the image size)

Width, Height: Dimensions of the image in pixels (always a power of two)

Offsets[0]: Offset from the start of the file to the image data
Lengths[0]: Length in bytes of the image data
Palette: 4-byte BGRA color values for paletted textures (this field is present regardless of whether the texture actually uses palettes)

I'm not familar enough with the more advanced aspects of C# to know where to begin with this. Or how to go about it.

Please an suggestions?

[RedSon]

I am not familiar enough with your question to understand what you are talking about. There are image libraries available in C# for you to use to manipulate images. Why would you re-invent the wheel?

[Samishii23]

My problem isn't simply working with another image file. Its not a supported file type, and I don't think simply calling the image would display anything useful in the program besides an Unsupported Type exception.

I was just wondering if there was a way in .NET to possible read that above header information for a binary level. I've seen libraries for the file format with programs out there, but I don't have the necessary information on the library to be able to use it for my project. I was wondering if anyone knew where I should begin.

[RedSon]

What is the file format?

[Samishii23]

.blp
Its a proprietary image format from Blizzard Inc.. Its used in alot of their 3D graphics and modeling. It uses a RBGA format based on jpeg library I believe.

Its about all I know about the format.
I posted the header information above.

[RedSon]

I'm not sure... you can try:

http://jonathankoff.com/Public/BLP_Viewer/BLP_Viewer.php

[Samishii23]

Refer to post #3.

I do have that program, however. I would like to be able to use said files in my own programs. And I can't just port a .dll without knowing what methods are in it. If I did alot of things would be easier.

[Plater]

http://en.wikipedia.org/wiki/DXT5

http://en.wikipedia.org/wiki/.BLP#BLP2_Format

You could parse the data yourself. You can read the header and setup a new Bitmap object from it.
Then you can scan through the image data building the correct pixel/color combinations from it and drawing them onto your Bitmap object.
It will not be easy.

[RedSon]

Yea, what he said, plus:

Good luck.

[Samishii23]

Hmm, your right thats alot of work.
Is it possible to get a push in the right direction?
My concern, is that because of my lack of experience. I don't know where to begin... Though reading the header of the file is the 1st step. Thats my problem. I have not an idea how to begin.
Once I know where to start the digging I should be able to carry my own weight.

Thank you in advance.

[Plater]

Well I think learning how to make the header struct correctly in managed code would be good.
Will need to look into StructLayout and Marshalling.
Since I happen to know first hand how difficult it is to find information on it, here's the struct:
[code=c#]
[StructLayout(La youtKind.Sequen tial, Pack = 1, CharSet = CharSet.Ansi)]
public struct BLP2Header
{
[MarshalAs(Unman agedType.ByValT Str, SizeConst = 4)]
public string ID;//FourCC = 4 character codes
public UInt32 Type;
public byte Encoding;
public byte AlphaDepth;
public byte AlphaEncoding;
public byte HasMips;
public UInt32 Width;
public UInt32 Height;//+7
[MarshalAs(Unman agedType.ByValA rray, SizeConst = 16)]
public UInt32[] Offsets;
[MarshalAs(Unman agedType.ByValA rray, SizeConst = 16)]
public UInt32[] Lengths;
[MarshalAs(Unman agedType.ByValA rray, SizeConst = 256)]
public byte[] Palette;
}
[/code]

Now look into how you can marshal the first 404 bytes of the file into that header struct

[Darky28]

I already wrote a C# lib for blp images

Howdy

I've already wrote a perfectly working C# lib (all managed) for asp.net that handles the blp image format.

At this point its a read lib.. so you can only load blps and display / convert em to gif / tiff / png e.t.c... but not convert something into blp.

Greets

Chris

If your interrested in the lib drop me a message in MSN: DELETED

[Samishii23]

H3ll yes I'm interested... I have added your contact info. Hope to catch you online.

[RedSon]

Do not post your email address. If you want to share email information use the PM feature of this site.