/* $Id: graphics.cpp,v 1.3 2005/06/28 13:55:19 chfreund Exp $ */

#include "graphics.hpp"

void Graphics::setPixel( SDL_Surface* surface, const int x, const int y, const Uint32 color ) {
	int bpp = surface->format->BytesPerPixel;
	Uint8 *p = static_cast<Uint8*>( surface->pixels ) + y * surface->pitch + x * bpp;
	
	switch ( bpp ) {
	case 1:
		*p = color;
		break;
	case 2:
		*( reinterpret_cast<Uint16*>( p ) ) = color;
		break;
	case 3:
		if ( SDL_BYTEORDER == SDL_BIG_ENDIAN ) {
			p[0] = ( color >> 16 ) & 0xff;
			p[1] = ( color >>  8 ) & 0xff;
			p[2] = color & 0xff;
		} else {
			p[0] = color & 0xff;
			p[1] = ( color >>  8 ) & 0xff;
			p[2] = ( color >> 16 ) & 0xff;
		}
		break;
	case 4:
		*( reinterpret_cast<Uint32*>( p ) ) = color;
		break;
	}
}

Uint32 Graphics::getPixel( SDL_Surface *surface, const int x, const int y ) {
	int bpp = surface->format->BytesPerPixel;
	Uint8 *p = static_cast<Uint8*>( surface->pixels ) + y * surface->pitch + x * bpp;
    
	switch ( bpp ) {
	case 1:
		return *p;
	case 2:
		return *( reinterpret_cast<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 *( reinterpret_cast<Uint32*>( p ) );
	default:
		return 0;
	}
}