Keskustelu: Ohjelmointikysymykset: C++: kuvan lukeminen/muokkaaminen

#include <SDL/SDL.h>
#include <stdlib.h>
#include <time.h>

#pragma comment(lib, "SDLmain.lib")
#pragma comment(lib, "SDL.lib")

SDL_Surface *screen;

Uint32 *bufp;
Uint8 *keys;
SDL_Event event;

void DrawIMG(SDL_Surface *img, int x, int y)  //kuvaan tarvittavat funktiot
{
	SDL_Rect dest;
	dest.x = x;
	dest.y = y;
	SDL_BlitSurface(img, NULL, screen, &dest);
}
void DrawIMG(SDL_Surface *img, int x, int y, int w, int h, int x2, int y2)
{
	SDL_Rect dest;
	dest.x = x;
	dest.y = y;
	SDL_Rect dest2;
	dest2.x = x2;
	dest2.y = y2;
	dest2.w = w;
	dest2.h = h;
	SDL_BlitSurface(img, &dest2, screen, &dest);
}
int SDL_BlitSurface(SDL_Surface *src, SDL_Rect *srcrect,
					SDL_Surface *dst, SDL_Rect *dstrect);

int main(int argc, char *argv[])
{
    if (SDL_Init(SDL_INIT_VIDEO) < 0)  // SDL
    {
        printf("Error to Init yms.. %s\n", SDL_GetError());
        exit(1);
    }

    atexit(SDL_Quit);

	SDL_Surface *pic = SDL_LoadBMP("pic.bmp");

	screen = SDL_SetVideoMode(pic->w, pic->h, 32, SDL_SWSURFACE);

    if (screen == NULL) {
        printf("Unable to set video mode.. sry .. &s\n", SDL_GetError());
        exit(1);
    }
	bool onko[800][800];
	int x, y;
	int a=10, vari=50;

	for(x=0;x<pic->w;x++)
	for(y=0;y<pic->h;y++)
	{
		bufp=(Uint32 *)pic->pixels + y*pic->pitch/4 + x;
		if(*bufp==SDL_MapRGB(pic->format, 0, 0, 0))
			onko[x][y]=true;
		else onko[x][y]=false;
	}

	SDL_SetColorKey(pic, SDL_SRCCOLORKEY,SDL_MapRGB(pic->format,255,0,255));

	while(1)
	{
		vari+=a;
		if(vari>255)a=-10;
		if(vari<50)a=10;

		for(x=0;x<pic->w;x++)
		for(y=0;y<pic->h;y++)
		{
			if(onko[x][y])
			{
				bufp = (Uint32 *)pic->pixels + y*pic->pitch/4 + x;
				*bufp = SDL_MapRGB(pic->format, 255, vari, vari);
			}
		}

		DrawIMG(pic, 0, 0);

		SDL_PollEvent(&event);
		if ( event.type == SDL_QUIT ) return 0;
		keys = SDL_GetKeyState(NULL);
		if ( keys[SDLK_ESCAPE]) break;

		SDL_Flip(screen);
	}
	return 0;
}