Why do you want to save all images in one file?

If the images are of the same size, a common technique is to use an "atlas". It could then be loaded as one single texture. Of course, the texture coordinates have to be adjusted accordingly. If the images are not of the same size, it is still possible, but a little more work needed. It is a technique sometimes used for loading fonts (also variable width).

There is an obvious reason to not use a single file, and that is that it makes it harder to read and decode. Storing one image in every file is easy.

But i suppose you have other requirements, not shown above. Maybe you want to make it harder for other to hack and modify your images? This is, however, a more difficult requirement.

One solution could be to use a zip format? That way, you can use a standard zip program to create your files. See http://www.zlib.net/.

Spirrwell,

what you are going to want to do is save all of the file information (width, height, pixel format, etc.) that is needed for passing it along to various subsystems for loading that data type, such as


glTexImage2D( GL_TEXTURE_2D, 0, nOfColors, surface->w, surface->h, 0,
texture_format, GL_UNSIGNED_BYTE, surface->pixels );


the way i have done this in the past is simply by writing a struct that contained this information right before the pixel or sound data itself. so the file would look something like


[number of items : 5]

[item1 image info]
[item1 image data]

[item2 image info]
[item2 image data]

[item3 image info]
[item3 image data]

[item4 image info]
[item4 image data]

[item5 image info]
[item5 image data]

[end of file]



obviously this is not the optimal solution, nor would it be beneficial to a complex development environment. but i have a feeling you dont need some kind of crazy impressive over thought out solution. pack the files like this, and run compression afterwords if you want. then you can figure out how to improve on it if you so desire. theres nothing wrong with doing this by the way. some people are way too by the book.

and as a side note. if you store textures of the same size (file size not JUST dimensions) in their own pak files, you can improve performance by keeping track of a textures index in this file format and seek right to it in memory by using something like (image index * textureSize)

This is the one area where I really hate pointers. How do I fwrite this pointer? I tried to research it and I ended up with something that doesn't make sense:

ahh yes, It's been a while since i've used SDL but i would assume that the void pointer to your pixels is the actual image data.

its void because of varrying pixel formats, 8 bit 16 bit , whatever.

i would reccomend casting it to a data type of that size. for example if 8bit, you could just use an unsigned char to represent each pixel.

if its 16 bits per pixel, you could do

typedef struct MyPixel
{
unsigned short r;
unsigned short g;
unsigned short b;
//unsigned short a; //alpha component if needed;
}


for 32 bits per pixel, use an unsigned int. and i'm unsigned because i'm assuming these will never be negative. it probably doesnt matter if signed or unsigned.

this way you can use a for loop, and indices to iterate through your pixel data. just cast to your new type


MyPixel* pixelData= (pixelData *) (memory address of your pixel data loaded from file);


and you will know the length of this array by the width/height values in the image info struct

i hope that helps sorry im kinda in a rush right now