gistfile1.txt

#include "SDL.h"

#define SCREEN_WIDTH  640
#define SCREEN_HEIGHT 480
#define SPRITE_SIZE    32


SDL_Texture *loadTexture(SDL_Renderer *renderer, const char *filename, int colorkey) {
    SDL_Surface *bmp = SDL_LoadBMP(filename);

  if (colorkey > 0) {
		SDL_SetColorKey(bmp, SDL_TRUE, colorkey);
	}

    SDL_Texture *texture = SDL_CreateTextureFromSurface(renderer, bmp);
    SDL_FreeSurface(bmp);
    return texture;
}


int main(int argc, char* argv[])
{
	SDL_Rect rcSprite, rcGrass;
	SDL_Event event;
	const Uint8 *keystate;

	int gameover;

	/* initialize video system */
	SDL_Init(SDL_INIT_EVERYTHING);
    SDL_Window *window = SDL_CreateWindow("SDL Move",
                                          SDL_WINDOWPOS_CENTERED,
                                          SDL_WINDOWPOS_CENTERED,
                                          SCREEN_WIDTH,
                                          SCREEN_HEIGHT,
                                          SDL_WINDOW_SHOWN);

    SDL_Renderer *renderer = SDL_CreateRenderer(window, -1, 
            SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);

	// int colorkey = SDL_MapRGB(window->format, 255, 0, 255);
    SDL_Texture *sprite = loadTexture(renderer, "sprite.bmp", 0);
    SDL_Texture *grass  = loadTexture(renderer, "grass.bmp", 0);

	/* set sprite position */
	rcSprite.x = 0;
	rcSprite.y = 0;

	gameover = 0;

	/* message pump */
	while (!gameover)
	{
		/* look for an event */
		if (SDL_PollEvent(&event)) {
			/* an event was found */
			switch (event.type) {
				/* close button clicked */
				case SDL_QUIT:
					gameover = 1;
					break;

				/* handle the keyboard */
				case SDL_KEYDOWN:
					switch (event.key.keysym.sym) {
						case SDLK_ESCAPE:
						case SDLK_q:
							gameover = 1;
							break;
                        case SDLK_LEFT:
                            rcSprite.x -= 5;
                            break;
                        case SDLK_RIGHT:
                            rcSprite.x += 5;
                            break;
                        case SDLK_UP:
                            rcSprite.y -= 5;
                            break;
                        case SDLK_DOWN:
			                rcSprite.y += 5;
                            break;
					}
					break;
			}
		}

		/* collide with edges of screen */
		if ( rcSprite.x < 0 ) {
			rcSprite.x = 0;
		}
		else if ( rcSprite.x > SCREEN_WIDTH-SPRITE_SIZE ) {
			rcSprite.x = SCREEN_WIDTH-SPRITE_SIZE;
		}
		if ( rcSprite.y < 0 ) {
			rcSprite.y = 0;
		}
		else if ( rcSprite.y > SCREEN_HEIGHT-SPRITE_SIZE ) {
			rcSprite.y = SCREEN_HEIGHT-SPRITE_SIZE;
		}

        rcGrass.x = 0;
        rcGrass.y = 0;
		rcGrass.w = 32;
		rcGrass.h = 32;

        SDL_RenderClear(renderer);
        SDL_RenderCopy(renderer, grass, NULL, &rcGrass);

		/* draw the grass */
		for (int x = 0; x < SCREEN_WIDTH / SPRITE_SIZE; x++) {
			for (int y = 0; y < SCREEN_HEIGHT / SPRITE_SIZE; y++) {
				rcGrass.x = x * SPRITE_SIZE;
				rcGrass.y = y * SPRITE_SIZE;
                SDL_RenderCopy(renderer, grass, NULL, &rcGrass);
			}
		}

		/* draw the sprite */
		rcSprite.w = 32;
		rcSprite.h = 32;
        SDL_RenderCopy(renderer, sprite, NULL, &rcSprite);
        SDL_RenderPresent(renderer);
	}

	/* clean up */
    SDL_DestroyTexture(sprite);
    SDL_DestroyTexture(grass);
    SDL_DestroyRenderer(renderer);
    SDL_DestroyWindow(window);
	SDL_Quit();

	return 0;
}