C++ transfer SDL_renderer to a class

Question

I am currently learning SDL2 and just managed to create a ping pong game. Some friends told me that I should start using classes for managing as an example player1 and player2. I know how to create a class but I do not understand how I would be able to pass SDL_Renderer between classes in order to render an object from within the class to the main.cpp file.

#include "SDL2/SDL.h"
#include "SDL2/SDL_render.h"
#include <iostream>
#include <windows.h>
#include <thread>
#include "player.h"

Player Player; //defining the class

const int WINDOW_WIDTH = 1280;
const int WINDOW_HEIGHT = 720;


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

SDL_Init(SDL_INIT_EVERYTHING);

SDL_Window *window;
SDL_Renderer *renderer;

window = SDL_CreateWindow    ("Test",
                            SDL_WINDOWPOS_CENTERED,
                            SDL_WINDOWPOS_CENTERED,
                            WINDOW_WIDTH,
                            WINDOW_HEIGHT,
                            0
                            );
if (window == NULL) {
    std::cout << "Window could not load" << SDL_GetError() << std::endl;
    return 0;
}

renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
while (running) //running is a bool (true) {
    Player.draw();
}
    SDL_DestroyWindow(window);
    SDL_Quit();
    return 0;
}

What do I have to do in my player.cpp draw function in order to draw an object on the screen?

Using C++ windows, compiling the code with g++ main.cpp player.cpp -o main.exe -IC:\MinGW\i686-w64-mingw32\include -LC:\MinGW\i686-w64-mingw32\lib -lmingw32 -lSDL2main -lSDL2

Pass the `window` and `renderer` pointers to the function as *arguments*? — Some programmer dude, Apr 17 '18 at 08:35
I might suggest learning more C++ before diving to deep into SDL. Will make your learning experience a lot more pleasant when the language doesn't get in your way. — Carl, Apr 17 '18 at 09:00
If you don't know even that, then please [get a few good books](https://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list/388282#388282) first and *learn basic C++*. — Some programmer dude, Apr 17 '18 at 09:59
Note that `SDL_CreateRenderer` requires that you call `SDL_DestroyRenderer` on the renderer after you're done using it, and before you destroy the associated window. Using Resource Acquisition tools like `std::unique_ptr` can help make this process more automatic — KABoissonneault, Apr 24 '18 at 13:28

score 1 · Accepted Answer · answered Apr 24 '18 at 13:21

In main.cpp

Player.draw(renderer)

(presuming you are using the same code as above, just pass "renderer" to the Player.draw() function.)

In player.h

class Player {
public:
    void draw(SDL_Renderer *renderer)
};

In player.cpp

void Player::draw(SDL_Renderer *renderer) {
    SDL_Rect object;
    object.x = 0;
    object.y = 0;
    object.h = 10;
    object.w = 10;
    SDL_SetRenderDrawColor(renderer, 255, 255, 255, 255);
    SDL_RenderDrawRect(renderer, &object);
    SDL_RenderFillRect(renderer, &object);
}
// will draw a white box with at position (0,0)

I believe this is a simple way to do it

C++ transfer SDL_renderer to a class

1 Answers1