/* gcc `sdl2-config --cflags` -o rect `sdl2-config --libs` rect.c
&& ./rect */
#include <SDL.h>

/* Create a 8x1 texture with 8 pixels of different color */
SDL_Texture *create_pattern(SDL_Renderer *renderer) {
	SDL_Texture *ret;	int i;
	//create 8x1 32bit surface
	SDL_Surface *surf = SDL_CreateRGBSurface(0,8,1,32,0,0,0,0);
	//fill with 8 colors
	for (i = 0; i < 8; i++) {
		SDL_Rect target;
		target.w = target.h = 1;
		target.y = 0; target.x = i;
		SDL_FillRect(surf, &target, 
		SDL_MapRGB(surf->format, rand()%255, rand()%255,
rand()%255)); }
	//create a texture from it
	ret = SDL_CreateTextureFromSurface(renderer, surf);
	SDL_FreeSurface(surf);
	return ret;
}
#define ZOOM 32
int main(int argc, char* argv[]) {
	SDL_Window* window;
	SDL_Renderer *renderer;
	SDL_Texture *pattern;
	SDL_Rect dstrect = { 0, 0, 8 * ZOOM, 1 * ZOOM };
	int done = 0;
	int x = ZOOM;
	int dx = -1;
	
	SDL_Init(SDL_INIT_VIDEO);
	SDL_CreateWindowAndRenderer(320, 240, SDL_WINDOW_SHOWN,
&window, &renderer); 
	pattern = create_pattern(renderer); //create our texture
	
	SDL_SetRenderDrawColor(renderer, 0, 0, 0, 0);
	
	while (!done) {
		SDL_Event event;
		SDL_zero(event);
		while (SDL_PollEvent(&event)) 
			if (event.type == SDL_QUIT) done = 1; 
		SDL_RenderClear(renderer);    		
		
		dstrect.x = x;
		dstrect.y = 0;
		//render this texture at x, 0
		SDL_RenderCopy(renderer, pattern, NULL, &dstrect);
		SDL_RenderPresent(renderer);
		SDL_Delay(100);
		//move x back and forth
		x += dx;
		if (x < -1 * ZOOM) dx = 1; 
		else if (x > 320 - 7 * ZOOM) dx = -1;
	}
	
	SDL_DestroyRenderer(renderer);
	SDL_DestroyWindow(window);
	SDL_Quit();
	return 0;
}