practice/sdl/whatever/whatever.c

#include "SDL2/SDL.h"
//Write a function that moves an image based on which arrow keys are pressed.
//something like
//functionize, everything
//void move_image(direction, image);

/* start SDL and create a window */
int init();

/* load the media durr */
int loadMedia();

/* Free the surfaces and whatnot */
void close_game();

/* Our main window */
SDL_Window* gScreen;

/*screen dimensions*/
const int screen_width = 1024;
const int screen_height = 768;

/* Our renderer */
SDL_Renderer* gRenderer;

/* Surface for loading BMP */
SDL_Surface* gTemp;

/* Texture for background */
SDL_Texture* gBackground_texture;

/* Texture for characters */
SDL_Texture* gPlayer;

/* Player coors */
SDL_Rect gPlayer_dest = { 0 };

int main ( int argc, char *argv[] )
{
	/* How fast our player moves */
	int movement_speed = 1;

	if (init() == 1)
	{
		printf("init failed!\n");
		close_game();
		return 1;
	}

	if (loadMedia() == 1)
	{
		printf("loadMedia failed!\n");
		close_game();
		return 1;
	}


	/*Event handler */
	SDL_Event e;
	
	/* quit if gameover is not 0 */
	int gameover = 0;

  /* message pump */
  while (!gameover)
  {
		/*handle events on queue */
		while ( SDL_PollEvent( &e ) != 0)
		{
			if (e.type == SDL_QUIT)
			{
				gameover = 1;
			}

		}

		const Uint8* currentKeyStates = SDL_GetKeyboardState( NULL );
		if (currentKeyStates[ SDL_SCANCODE_ESCAPE ] || 
				currentKeyStates[ SDL_SCANCODE_Q ] )
		{
			gameover = 1;
		}

		if (currentKeyStates[ SDL_SCANCODE_LEFT ] )
		{
			gPlayer_dest.x -= movement_speed;
		}
		if (currentKeyStates[ SDL_SCANCODE_RIGHT ] )
		{
			gPlayer_dest.x += movement_speed;
		}
		if (currentKeyStates[ SDL_SCANCODE_UP ] )
		{
			gPlayer_dest.y -= movement_speed;
		}
		if (currentKeyStates[ SDL_SCANCODE_DOWN ] )
		{
			gPlayer_dest.y += movement_speed;
		}


  	/* render the background */
		SDL_RenderCopy(gRenderer, gBackground_texture, NULL, NULL);

		/* Render entire gPlayer to center of screen */
		SDL_RenderCopy(gRenderer, gPlayer, NULL, &gPlayer_dest);

		/* Render here */
		SDL_RenderPresent(gRenderer);
	}


  return 0;

}

int init()
{

  /* initialize SDL */
  if (SDL_Init(SDL_INIT_EVERYTHING) != 0){
		printf("Unable to init SDL!: %s\n", SDL_GetError());
		return 1;
	}
  /* create window of size 640x480 and set title bar*/ 
	gScreen = SDL_CreateWindow("SDL TEST", 
														SDL_WINDOWPOS_CENTERED,
														SDL_WINDOWPOS_CENTERED,
														screen_width, screen_height,
														0);
	if (gScreen == NULL){
		printf("Unable to set video mode: %s\n", SDL_GetError());
		return 1;
	}
	
	return 0;
}

int loadMedia()
{
	const char background_imagefile[] = "sdl_logo.bmp";

	gRenderer = SDL_CreateRenderer(gScreen, -1, 0);

	if (gRenderer == NULL){
		printf("Unable to create renderer: %s\n", SDL_GetError());
	}
  /* load background bitmap to surface */
  gTemp = SDL_LoadBMP(background_imagefile);

	if (gTemp == NULL){
		printf("Unable to find image!!: %s\n", SDL_GetError());
		return 1;
	}
	else{
  /* convert bitmap to texture */
		gBackground_texture = SDL_CreateTextureFromSurface(gRenderer, gTemp);
		SDL_FreeSurface(gTemp); // No longer need the surface
		gTemp = NULL;
		if(gBackground_texture == NULL) {
			printf("Failed to create texture from background surface: %s\n", SDL_GetError());
			return 1;
		}
	}
	
	/* load gPlayer image to practice blit on top of surface*/
	gTemp = SDL_LoadBMP("dinowheel.bmp");
	if (gTemp == NULL){
		printf("Unable to load gPlayer: %s/n", SDL_GetError());
		return 1;
	}
	else{
		gPlayer = SDL_CreateTextureFromSurface(gRenderer, gTemp);
		SDL_FreeSurface(gTemp);
		gTemp = NULL;

		if(gPlayer == NULL) {
			printf("Failed to create texture from gPlayer: %s\n", SDL_GetError());
			return 1;
		}

	}

	int player_image_width, player_image_height;

	/* Get height and width of gPlayer */
	SDL_QueryTexture(gPlayer, NULL, NULL, &player_image_width, &player_image_height);
		
	/* Prepare gPlayer for inital position */
	gPlayer_dest.x = (screen_width / 2) - (player_image_width / 2);
	gPlayer_dest.y = (screen_width / 2) - (player_image_height / 2);
	gPlayer_dest.w = player_image_width;
	gPlayer_dest.h = player_image_height;
	
	return 0;

}

void close_game()
{

  /* cleanup SDL */
	if (gRenderer) SDL_DestroyRenderer(gRenderer);
	if (gScreen) SDL_DestroyWindow(gScreen);
	if (gBackground_texture) SDL_DestroyTexture(gBackground_texture);
	if (gPlayer) SDL_DestroyTexture(gPlayer);

  SDL_Quit();
}