Draw an Image with SDL2

openicon.c

#include <stdio.h>
#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>

#define WIDTH 800
#define HEIGHT 600
#define IMG_PATH "exit.png"

int main (int argc, char *argv[]) {

	// variable declarations
	SDL_Window *win = NULL;
	SDL_Renderer *renderer = NULL;
	SDL_Texture *img = NULL;
	int w, h; // texture width & height
	
	// Initialize SDL.
	if (SDL_Init(SDL_INIT_VIDEO) < 0)
			return 1;
	
	// create the window and renderer
	// note that the renderer is accelerated
	win = SDL_CreateWindow("Image Loading", 100, 100, WIDTH, HEIGHT, 0);
	renderer = SDL_CreateRenderer(win, -1, SDL_RENDERER_ACCELERATED);
	
	// load our image
	img = IMG_LoadTexture(renderer, IMG_PATH);
	SDL_QueryTexture(img, NULL, NULL, &w, &h); // get the width and height of the texture
	// put the location where we want the texture to be drawn into a rectangle
	// I'm also scaling the texture 2x simply by setting the width and height
	SDL_Rect texr; texr.x = WIDTH/2; texr.y = HEIGHT/2; texr.w = w*2; texr.h = h*2; 
	
	// main loop
	while (1) {
		
		// event handling
		SDL_Event e;
		if ( SDL_PollEvent(&e) ) {
			if (e.type == SDL_QUIT)
				break;
			else if (e.type == SDL_KEYUP && e.key.keysym.sym == SDLK_ESCAPE)
				break;
		} 
		
		// clear the screen
		SDL_RenderClear(renderer);
		// copy the texture to the rendering context
		SDL_RenderCopy(renderer, img, NULL, &texr);
		// flip the backbuffer
		// this means that everything that we prepared behind the screens is actually shown
		SDL_RenderPresent(renderer);
		
	}
	
	SDL_DestroyTexture(img);
	SDL_DestroyRenderer(renderer);
	SDL_DestroyWindow(win);
	
	return 0;
}

Thanks for the gist, it really helped me. Possible improvements:

• To center the image:

    SDL_Rect rectangle;
    SDL_QueryTexture(texture, NULL, NULL, &rectangle.w, &rectangle.h);
    rectangle.x = (WIDTH - rectangle.w) / 2;
    rectangle.y = (HEIGHT - rectangle.h) / 2;

• You should use SDL_WaitEvent instead of SDL_PollEvent

    while (1) {
        // https://stackoverflow.com/questions/12770098/how-to-keep-the-cpu-usage-down-while-running-an-sdl-program
        SDL_Event e;
        if (SDL_WaitEvent(&e)) {
            if (e.type == SDL_QUIT)
                break;
            else if (e.type == SDL_KEYUP && e.key.keysym.sym == SDLK_ESCAPE)
                break;
        }
        
        SDL_RenderClear(renderer);
        SDL_RenderCopy(renderer, texture, NULL, &rectangle);
        SDL_RenderPresent(renderer);
    }

• Do not forget to free the surface in the end

    SDL_DestroyTexture(texture);
    SDL_FreeSurface(surface);
    SDL_DestroyRenderer(renderer);
    SDL_DestroyWindow(win);

saved my life i'm gonna pass my course now thanks my brother

Thanks for the gist, it really helped me. Possible improvements:

• To center the image:

    SDL_Rect rectangle;
    SDL_QueryTexture(texture, NULL, NULL, &rectangle.w, &rectangle.h);
    rectangle.x = (WIDTH - rectangle.w) / 2;
    rectangle.y = (HEIGHT - rectangle.h) / 2;

• You should use SDL_WaitEvent instead of SDL_PollEvent

    while (1) {
        // https://stackoverflow.com/questions/12770098/how-to-keep-the-cpu-usage-down-while-running-an-sdl-program
        SDL_Event e;
        if (SDL_WaitEvent(&e)) {
            if (e.type == SDL_QUIT)
                break;
            else if (e.type == SDL_KEYUP && e.key.keysym.sym == SDLK_ESCAPE)
                break;
        }
        
        SDL_RenderClear(renderer);
        SDL_RenderCopy(renderer, texture, NULL, &rectangle);
        SDL_RenderPresent(renderer);
    }

• Do not forget to free the surface in the end

    SDL_DestroyTexture(texture);
    SDL_FreeSurface(surface);
    SDL_DestroyRenderer(renderer);
    SDL_DestroyWindow(win);

You write some more code that could be added and changed later, for now the gist code is for setting up fast a project. But you believe too, that it is a good gist to use?

You write some more code that could be added and changed later, for now the gist code is for setting up fast a project. But you believe too, that it is a good gist to use?

IMHO, the gist is good once you apply the changes I suggested. The code will remain short because this is mainly updating few lines of the existing code. In the detail:

1. The first change (SDL_rect) is cosmetic. Without doing this, the image is in general not centered
2. The second change (SDL_WaitEvent) is very important. If you use SDL_PollEvent, the program uses 100% CPU (because it permanently refreshes the displayed image, which is useless). With the change I suggest, this problem disappears
3. The third change (SDL_FreeSurface) is recommended because otherwise you might have a memory leak as you don't destroy the object.

WaitEvent, waits for events, which is more for applications than games, because if you use it in a game, the entire game would hang until it gets an event, so there is no definitive option, hence you can choose

the CPU of the example can be very easly bypassed while still using poll events, just add an SDL_Delay
best also to explain that if someone were to make a game using this, that itd be best to use PollEvents with a frame-limiter/vsync

i love you

gay

How the heck is he or even she gay by loving someone??

Damn, why are all those people still here. Bros need to get a life.

Go contribute to some open-source projects!

i love you

gay

How the heck is he or even she gay by loving someone??

i was joking

very funny