draw.cpp

#include "headers/draw.h"

Uint32 getpixel(SDL_Surface *surface, int x, int y)
{
    int bpp = surface->format->BytesPerPixel;
    /* Here p is the address to the pixel we want to retrieve */
    Uint8 *p = (Uint8 *)surface->pixels + y * surface->pitch + x * bpp;

    switch (bpp)
    {
        case 1:
            return *p;

        case 2:
            return *(Uint16 *)p;

        case 3:
            if (SDL_BYTEORDER == SDL_BIG_ENDIAN)
                return p[0] << 16 | p[1] << 8 | p[2];
            else
                return p[0] | p[1] << 8 | p[2] << 16;

        case 4:
            return *(Uint32 *)p;

        default:
            return 0;       /* shouldn't happen, but avoids warnings */
    }
}