Image format question

Question

Hey there,

I'm using an image loader (DevIL) for image loading. Im just wondering if the image format (the uncompressed format in memory) loaded from files (.jpg, .png, .bmp etc) is determined by the image loading program itself, or is some way contingent upon the actual image file.

All of the images I have looked at so far seem to be loaded into the RGBA / UNSIGNED_BYTE format. However I am wondering if I can always rely on this. Is it conceivable that an image might actually be loaded into the RGBA / FLOAT format instead? (NOTE: i am hoping that the loaded image format will always be the same, i want to rely on it:)

I can't find any docs in DevIL that explains this point, so I'm hoping anyone experienced with imaging / image loading could give me an answer just based on their experience / common sense.

Thanks

Answer 1

I don't know DevIL, but nearly any imaging library is going to provide you with an image object that has some concept of Pixel Format. The pixel format tells you how the image is laid out in memory. Looking quickly at the docs, I see that IlTexImage has a property called Format which can be one of IL_COLOUR_INDEX, IL_RGB, IL_RGBA, etc. The docs say

The format of the image data. Formats accepted are listed here and are self-explanatory