Game Engine

// Compile With: g++ LQGE.h main.cpp -lSDL2 -lSDL_image -o "Butter Game"

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

// Errors
#define LQGE_SUCCESS 0
#define LQGE_INITIALIZATION_ERROR 1
#define LQGE_IMAGE_INITIALIZATION_ERROR 2
#define LQGE_WINDOW_CREATION_ERROR 3
#define LQGE_RENDERER_CREATION_ERROR 4
#define LQGE_IMAGE_LOADING_ERROR 5

// Constants Needed
#define WINDOW_CENTER_X 1920/2
#define WINDOW_CENTER_Y 1080

// The Window And Renderer And Other Important Stuff
SDL_Window* window;
SDL_Renderer* renderer;

SDL_Texture* backgroundTexture;

bool running = true;
bool fullscreen;

int LQGE_CreateWindow(int posX, int posY, int sizeX, int sizeY, bool fullscreen)
{
	if(SDL_Init(SDL_INIT_EVERYTHING) != 0){return LQGE_INITIALIZATION_ERROR;}
	if(IMG_Init(IMG_INIT_PNG) == 0){return LQGE_IMAGE_INITIALIZATION_ERROR;}
	if(fullscreen){window = SDL_CreateWindow("Untitled Butter Game", posX, posY, sizeX, sizeY, SDL_WINDOW_FULLSCREEN); fullscreen = true;}
	if(!fullscreen){window = SDL_CreateWindow("Untitled Butter Game", posX, posY, sizeX, sizeY, SDL_WINDOW_SHOWN); fullscreen = false;}
	if(window == NULL){return LQGE_WINDOW_CREATION_ERROR;}

	renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_PRESENTVSYNC);
	if(renderer == NULL){return LQGE_RENDERER_CREATION_ERROR;}

	return LQGE_SUCCESS;
}

void quit()
{
	SDL_DestroyRenderer(renderer);
	SDL_DestroyWindow(window);
	IMG_Quit();
	SDL_Quit();

	running = false;
}

int LQGE_ChangeBackground(const char* path)
{
	SDL_Surface* backgroundSurface;

	backgroundSurface = IMG_Load(path);
	if(backgroundSurface == NULL){return LQGE_IMAGE_LOADING_ERROR;}
	backgroundTexture = SDL_CreateTextureFromSurface(renderer, backgroundSurface);
	if(backgroundTexture == NULL){return LQGE_IMAGE_LOADING_ERROR;}

	return LQGE_SUCCESS;
}

void LQGE_RenderScreen()
{
	SDL_RenderClear(renderer);

	SDL_RenderCopy(renderer, backgroundTexture, NULL, NULL);

	SDL_RenderPresent(renderer);
}

void LQGE_GetInput()
{
	SDL_Event event;

	while(SDL_PollEvent(&event) != 0)
	{
		switch(event.type)
		{
			case SDL_QUIT:
				quit();
				break;
			case SDL_KEYDOWN:
				switch(event.key.keysym.sym)
				{
					case SDLK_F4:
						if(fullscreen)
						{
							SDL_SetWindowFullscreen(window, 0);
							fullscreen = false;
						}
						else if(!fullscreen)
						{
							SDL_SetWindowFullscreen(window, SDL_WINDOW_FULLSCREEN);
							fullscreen = true;
						}
						break;
					default:
						break;
				}
				break;
			default:
				break;
		}
	}
}