function.c

/*
Copyright (C) 2007 Slempkes Clément

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include <SDL/SDL.h>
#include "main.h"

void setPixel(SDL_Surface *surface, int x, int y, Uint32 pixel)
{
    int bpp = surface->format->BytesPerPixel;

    Uint8 *p = (Uint8 *)surface->pixels + y * surface->pitch + x * bpp;

    switch(bpp) {
    case 1:
        *p = pixel;
        break;

    case 2:
        *(Uint16 *)p = pixel;
        break;

    case 3:
        if(SDL_BYTEORDER == SDL_BIG_ENDIAN) {
            p[0] = (pixel >> 16) & 0xff;
            p[1] = (pixel >> 8) & 0xff;
            p[2] = pixel & 0xff;
        } else {
            p[0] = pixel & 0xff;
            p[1] = (pixel >> 8) & 0xff;
            p[2] = (pixel >> 16) & 0xff;
        }
        break;

    case 4:
        *(Uint32 *)p = pixel;
        break;
    }
}
Uint32 readColor32(SDL_Surface* surface, int x, int y)
{
    int bpp = surface->format->BytesPerPixel;

    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;
    }
}
color readColor(SDL_Surface * surface, int x, int y)
{
    color returnColor;

    if (x >= 0 && x <= surface->w)
    {
        if (y >= 0 && y <= surface->h)
        {
            SDL_GetRGB(readColor32(surface, x, y), surface->format, (Uint8*) &returnColor.r, (Uint8*) &returnColor.g, (Uint8*) &returnColor.b);
        }
        else{returnColor.r = 0;returnColor.g = 0;returnColor.b = 0;}
    }
    else
    {
        returnColor.r = 0;
        returnColor.g = 0;
        returnColor.b = 0;
    }

    return returnColor;
}
int cont(int Nbr)
{
    if ((Nbr = -Nbr))Nbr = +Nbr;
    else Nbr = -Nbr;
    return Nbr;
}