Thread: Return some kind of array or structure?

Hey people

I'm making a function to load an opengl texture, but instead of returning the texture ID as GLuint, I want it to return also other values such as width, height, etc. So I can access them as pointers. Something like this pseudo-code:

Code:

tex = LoadTexture("texture.jpg");

printf("Width: %i \n",tex->width);
printf("Height: %i \n",tex->height);

BindToSprite(tex->TextureID);

What are the steps I'll need to follow in order to return something like that? I know I can have a structure to hold values since I have one that holds the FPS and other global variables, but how would I go into returning a structure of its own, that's not global but that can be spawned as many textures as I want to load?

Thanks in advance!

Make a class that acts as a container for image data. That way the member functions just load the texture into the class itself.

Originally Posted by indigo0086

Make a class that acts as a container for image data. That way the member functions just load the texture into the class itself.

Yeah, the thing is... how? I mean, I know theories but I don't know how to do it code-wise :/ that was my idea too, using a class, but I dunno how would it apply in my case, code-wise.

Thanks for the fast reply though!

So your header file would look something like this

Code:

typedef struct
{
   int width, height;
   int alpha;  //etc...
} header;

class BMPimg
{
   header* BMPheader;
   unsigned char imgData[]; //array that will hold your data 
   public:
       BMPimg(const char* fileName) { //loads file and manipulates private data and header info}
       ~BMPimg();
       int getWidth() { return BMPheader.width; }
       int getHeight() { return BMPheader.height; }
       unsigned char* retData { return imgData }
      //etc....
}

this way when you need to create an image using pointers you do this

Code:

int main()
{
    BMPimg* Happyface = new BMPimg("happyface.bmp");
   
    //do what you will with the image such as
    glDrawPixels(HappyFace->getWidth(), HappyFace->getHeight(), //etc);
    delete HappyFace;

    return 0
}

Originally Posted by indigo0086

So your header file would look something like this

Code:

typedef struct
{
   int width, height;
   int alpha;  //etc...
} header;

class BMPimg
{
   header* BMPheader;
   unsigned char imgData[]; //array that will hold your data 
   public:
       BMPimg(const char* fileName) { //loads file and manipulates private data and header info}
       ~BMPimg();
       int getWidth() { return BMPheader.width; }
       int getHeight() { return BMPheader.height; }
       unsigned char* retData { return imgData }
      //etc....
}

this way when you need to create an image using pointers you do this

Code:

int main()
{
    BMPimg* Happyface = new BMPimg("happyface.bmp");
   
    //do what you will with the image such as
    glDrawPixels(HappyFace->getWidth(), HappyFace->getHeight(), //etc);
    delete HappyFace;

    return 0
}

COOL! exactly what I was looking for! ^^... thanks hehe I'm going to work right now but when I'm back home I'll try that... I didn't know you could place an "identifier" to the class right after the closing bracket... now it makes sense, huge thanks!

header* BMPheader;
should be
header BMPheader;

Well, I tried your code... and I'm confused because if I try to modify the value inside the function (for example, to change the value in BMPheader.width ) it says it's not declared in that ambit... how can I solve that? :/ the code looks ok to me, but C++ is frickin' weird as always >.<

Inside

Code:

BMPimg(const char* fileName) { //loads file and manipulates private data and header info}

try adding BMPheader.width = 100; between the brackets. It doesn't work for me :/