Dynamic Structure Array Help

I need to dynamically create this structure array, at the beginning of my program and when the window is updated.

I am using GLUT (OpenGL) to create a gradient fill image and draw it's pixels on the screen, and I need the image to update itself when the window is resized.

Does anyone know how to get it working with malloc to dynamically create the array? Thanks in advance.

Code:

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/* my image structure */
typedef struct tagColour{
        float r; /* red  */
        float g; /* green */
        float b; /* blue  */
} PIXEL_COLOUR;

PIXEL_COLOUR pixel_image[PIXEL_WIDTH][PIXEL_HEIGHT];

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You'll need to use a pointer to a pointer instead, assuming you want a dynamic "2D array".

Code:

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something **foo;

foo = malloc( sizeof( something* ) * num_of_rows );
for( x = 0; x < num_of_columns; x++ )
    foo[x] = malloc( sizeof( something ) * num_of_columns );

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Be sure and free each column and row correctly when you're done.

Quzah.

Can this code be used in the image[x][y] structure format?

Just figured out another solution to my code problem. Thanks. :)

Quote:

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Originally posted by quzah
You'll need to use a pointer to a pointer instead, assuming you want a dynamic "2D array".

Code:

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something **foo;

foo = malloc( sizeof( something* ) * num_of_rows );
for( x = 0; x < num_of_columns; x++ )
    foo[x] = malloc( sizeof( something ) * num_of_columns );

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Be sure and free each column and row correctly when you're done.

Quzah.

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I ran into another problem last night, and I want to copy my image data (which is in the format image[x][y] into a temp image, but it needs to be dynamic because the image size is always changing) to a temp_image structure. (Note: image[x][y] is a structure with three float values for RGB data).

Will the above example work in the context temp_image[x][y] ?

If not, does anyone know a way?

Thanks again.

Quote:

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Originally posted by B_D_C
Will the above example work in the context temp_image[x][y] ?

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Yes.

Quzah.

Quote:

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Originally posted by quzah
Yes.

Quzah.

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So that initializes both the first and second elements of the array?

Quote:

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Originally posted by B_D_C
So that initializes both the first and second elements of the array?

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Try it and find out. I've already answered.

Quzah.

Quote:

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Originally posted by quzah
Try it and find out. I've already answered.

Quzah.

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Yeah, I tried it out yesterday and it works. :)

However, I found that I didn't even need to use 2D dynamic array. Thanks for your help.