main.cpp

#include <iostream>
#include <SDL.h>
#include <SDL_image.h>
#include <filesystem>
#include "SDLTest.h"
#include "Texture.h"

/*
* This is just an example code to help you started. It has design issues, missing classes
* and smart pointers so don't take it as a stable base.
* It also has some ideas (Texture class, anyone?) and shows how to use several important
* parts of SDL and how to load a texture with SDL_Image.
* So, I recommend to check it out, read the SDL documentation about the used functions and
* make your own version what fits for you!
*
* NOTE: IMG_LoadTexture_RW is not in the SDL_Image documentation because the docs is old but
* you can find some info in the source code of SDL_Image. Or just use it as I do here. :)
* */


// returns with true if we should quit. FYI: this is not a good practice :)
bool handleEvents(SDL_Rect& r)
{
  bool quit = false;
  //Event handler
  SDL_Event e;
  while (SDL_PollEvent(&e) != 0) // poll for events received from user or operating system
  {
    //User requests quit
    if (e.type == SDL_QUIT)
    {
      quit = true;
    }
    if (e.type == SDL_MOUSEBUTTONDOWN)
    {
      r.w += 20;
      r.h += 20;
    }

    if (e.type == SDL_MOUSEBUTTONUP)
    {
      r.w -= 20;
      r.h -= 20;
    }
  }
  return quit;
}

void updatePosition(const int windowWidth, const int windowHeight, SDL_Rect& r)
{
  // change the position of the rectangle what is used to draw the second texture
  r.x += 5; r.y += 5;
  if (r.x > windowWidth &&
      r.y > windowHeight)
  {
    r.x = 0;
    r.y = 0;
  }
}

int main(int, char**) {
  SDLTest test;
  test.init();
  // load pictures
  auto path = std::filesystem::current_path().parent_path();
  path /= "pic";
  Texture pic00 = test.loadBMP((path/"test1.bmp").string());
  Texture pic01 = test.loadTexture((path/"test1.png").string());

  // get window sizes for te loop
  int windowWidth;
  int windowHeight;
  test.getWindowSize(windowWidth, windowHeight);

  // setup a size for the second picture
  SDL_Rect r;
  r.x = 0; r.y = 0;
  r.w = 100; r.h = 100;

  // wait a little so the animation won't start before the window appears
  SDL_Delay(100);

  bool quit = false;
  Uint32 timePassed = 0;
  Uint32 timestep = 16; // we want 60fps what is 1000 ms / 60 = 16.6 frame per seconds so timestep is 16

  // main loop, drawing happens here
  while (!quit) {
    timePassed = SDL_GetTicks();

    quit = handleEvents(r);

    //First clear the renderer
    SDL_RenderClear(test.getRenderer());

    pic00.render(test.getRenderer(), nullptr);
    pic01.render(test.getRenderer(), &r);

    //Update the screen
    SDL_RenderPresent(test.getRenderer());

    updatePosition(windowWidth, windowHeight, r);

    // wait until the time declared in timestep passes
    while (timePassed + timestep > SDL_GetTicks()) {
      SDL_Delay(0);
    }
  }

  return 0;
}