[Development] qdds image format

[Giuseppe D'Angelo]

On 17/04/18 08:09, Иван Комиссаров wrote:
>> Looking at the email archives: it was fuzzed through AFL. I don't have the test images still around, but in my experience a simple multi-image file was enough to trigger a crash. (I used to see this in Creator, when accidentally opening a DDS in its builtin image preview).
> What is AFP?

American Fuzzy Lop: http://lcamtuf.coredump.cx/afl/

>> But again, why having such an image loader in Qt? It's not going to be useful in 99.9% of the use cases where you use a DDS file.
> Well, opening DDS file in Qt Creator is that «0.01%» usecase, but it’s quite convenient to do such thing. In case it doesn’t crash, though:(

I wasn't trying to open it to do anything meaningful, it was because the 
DDS was in a resource file and Creator tries to build an icon for it or 
tries to visualize it when clicked. This triggered the crash in the DDS 
imageformat plugin.

> Or you’re developing a game and you need a map/level qwidget-based editor - it definitely should be able to open (and save) such textures. > Or you’re writing an archiver for a game with a file preview.

The problem I'm talking about is the API, not the feature itself: to 
properly handle DDS files you can't use QImage and QImageReader. So why 
having such support in a qtimageformat?

We're talking about a format meant to store textures: how do you 
retrieve a mipmap chain using QImageReader? How do you retrieve a 
specific array level? How do you retrieve a specific cubemap face? How 
do you handle the formats that DDS can store and QImage can't represent?

If the idea is to use a more specialized API for DDS files, I'm all for 
it -- as I said before, let's add it to QtGui, and work with other 
texture containers (KTX, etc.). My concern is about using QImage and its 
APIs for this.

My 2 cents,
-- 
Giuseppe D'Angelo | giuseppe.dangelo at kdab.com | Senior Software Engineer
KDAB (France) S.A.S., a KDAB Group company
Tel. France +33 (0)4 90 84 08 53, http://www.kdab.com
KDAB - The Qt, C++ and OpenGL Experts

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