Loading .PNG in SDL2 in 78 lines.

loadpng.cpp

//Including SDL and standard headers.
//Note that you'll have to include all the libraries and include paths,
//and on Windows include a copy of SDL.dll and SDL_image.dll in the application directory.
#include <SDL.h>
#include <SDL_image.h>
#include <stdio.h>
#include <string>

//Predefining functions/variables.
SDL_Surface* loadPNGSurface(std::string);
SDL_Window* window = NULL;
SDL_Surface* window_surf = NULL;
SDL_Surface* loaded_surf = NULL;

//Spinning up surface in main.
int main(int argc, char* argv[]) {
	//Initializing SDL.
	if (SDL_Init(SDL_INIT_VIDEO) < 0) {
		printf("Error: Could not initialise SDL.");
	}
	else {
		//Loading the window.
		window = SDL_CreateWindow("PNG Loading Test", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 800, 600, SDL_WINDOW_SHOWN);
		//Loading the surface from said window.
		window_surf = SDL_GetWindowSurface(window);

		//Initializing PNG processing.
		if (IMG_Init(IMG_INIT_PNG) < 0) {
			printf("Error: Failed to load PNG processing.");
		}

		//Now testing PNG loading onto surfaces!
		loaded_surf = loadPNGSurface("img/test.png");

		//Scaling and updating window.
		SDL_Rect window_rect;
		window_rect.x = 0;
		window_rect.y = 0;
		window_rect.w = 800;
		window_rect.h = 600;

		SDL_BlitScaled(loaded_surf, NULL, window_surf, &window_rect);
		SDL_UpdateWindowSurface(window);

		//Waiting for quit.
		bool quit = false;
		SDL_Event e;
		while (!quit) {
			while (SDL_PollEvent(&e) != 0) {
				//Checking for quit flag.
				if (e.type == SDL_QUIT) {
					quit = true;
				}
			}
		}
	}

	return 0;
}

//Function for loading PNG/other image files.
SDL_Surface* loadPNGSurface(std::string path) {
	//Creating final surface.
	SDL_Surface* loadedSurf;

	//Loading file to surface.
	loadedSurf = IMG_Load(path.c_str());

	if (loadedSurf == NULL) {
		printf("Error: Failed to load texture %s.", path);
	}

	//Optimizing surface.
	SDL_Surface* finalSurf = SDL_ConvertSurface(loadedSurf, window_surf->format, NULL);
	//Freeing unoptimised surface, returning.
	SDL_FreeSurface(loadedSurf);
	return finalSurf;
}