file - Getting RGB values for each pixel from a 24bpp Bitmap for conversion to GBA format in C

Question

I want to read the RGB values for each pixel from a .bmp file, so I can convert the bmp into a format suitable for GBA (GameBoy Advance).

I need to get just the RGB for each pixel and then write this information to a file.

I am trying to use the <windows.h> structures:

typedef struct
{
    char signature[2];
    unsigned int fileSize;
    unsigned int reserved;
    unsigned int offset;
}BmpHeader;

typedef struct
{
    unsigned int headerSize;
    unsigned int width;
    unsigned int height;
    unsigned short planeCount;
    unsigned short bitDepth;
    unsigned int compression;
    unsigned int compressedImageSize;
    unsigned int horizontalResolution;
    unsigned int verticalResolution;
    unsigned int numColors;
    unsigned int importantColors;

}BmpImageInfo;

typedef struct
{
    unsigned char blue;
    unsigned char green;
    unsigned char red;
    unsigned char reserved;
}Rgb;

typedef struct
{
    BmpHeader header;
    BmpImageInfo info;
    Rgb colors[256];
    unsigned short image[1];
}BmpFile;

but I only need RGB struct. So let's say I read "in.bmp":

FILE *inFile, *outFile;
inFile = fopen("C://in.bmp", "rb");

Rgb Palette[256];
for(i=0;i<256;i++)
{
   fread(&Palette[i],sizeof(Rgb),1,inFile);
}

fclose(inFile);

Is this correct? How do I write only the RGB information to a file?

Answer 1

If you are on windows you can use the LoadBitmap function from win32

then given the handle convert it to a DIB bitmap and get to the pixels that way