passing variable to multiple classes - C++ - c++

Question

i'm new and still learning OOP and SDL for educational purpose.
so, i have a variable SDL_Renderer renderer. this variable needs to be initiated only once, and i initiate it in GameManager class.
and i have another class named Texture that needs that renderer.
this Texture will be used frequently.
so how do i pass this renderer? do i have to call GameManager in the Texture class? but if i do that, it means that i makeGameManager everytime i use the Texture right? or there is another way around?
thank you for helping me, i'm really sorry if my question is vague or not clear.
EDIT
this is Texture class
class Texture
{
public:
Texture();
~Texture();
int getWidth();
int getHeight();
bool loadFromFile(std::string path);
bool loadTextFromFile(std::string text, SDL_Color textColor, TTF_Font* font);
void render(int x, int y, SDL_Rect* clip = NULL);
void free();
bool lockTexture();
bool unlockTexture();
void* getPixels();
int getPitch();
private:
int vWidth;
int vHeight;
SDL_Texture* vTexture;
SDL_Renderer* renderer;
void* pPixels;
int pPitch;
};
this is the initiator
Texture::Texture()
{
vTexture = NULL;
vWidth = 0;
vHeight = 0;
renderer = GameManager::getRenderer();
}
this is GameManager class
class GameManager
{
public:
GameManager();
~GameManager();
bool intializeGame();
void gameLoop();
static SDL_Renderer* getRenderer();
private:
SDL_Window* window = NULL;
static SDL_Renderer* renderer;
TTF_Font* font = NULL;
const int SCREEN_WIDTH = 640;
const int SCREEN_HEIGHT = 480;
};
the getRenderer() just a getter to pass the renderer
and this is my Main
int main(int argc, char* args[])
{
GameManager gameManager;
gameManager.intializeGame();
Texture charTexture;
SDL_Rect rect;
bool text = charTexture.loadFromFile("foo.png");
if (!text)
{
printf("texture not loaded");
}
rect.x = 0;
rect.y = 0;
rect.w = charTexture.getWidth();
rect.h = charTexture.getHeight();
while (true)
{
SDL_SetRenderDrawColor(GameManager::getRenderer(), 0xFF, 0xFF, 0xFF, 0xFF);
SDL_RenderClear(GameManager::getRenderer());
charTexture.render(10, 10, &rect);
SDL_RenderPresent(GameManager::getRenderer());
}
return 0;
}
i hope it's not confusing.

Answer 1

Disclaimer : I've never used SDL. This might be terrible, but it's based on what you gave me.
The important thing is the ownership. This is a shared ownership example. It's quite simple and takes the burden of figuring out when to destroy SDL_Renderer off of you.
class GameManager {
//BLABGLABLA
public:
std::shared_ptr<SDL_Renderer> getRenderer();
private:
std::shared_ptr<SDL_Renderer> renderer
}
class Texture
{
public:
Texture(std::shared_ptr<SDL_Renderer> theRenderer, //some other args)
private:
std::shared_ptr<SDL_Renderer> renderer;
}
So based on the name of the classes alone, you probably want GameManager to own the renderer, but you also want Texture to have access to it.
One way you can do that is to have a shared_ptr member in both classes, and to pass the renderer to texture in its constructor.
Basically the renderer object you initialized in GameManager, will only be destroyed when the last shared_ptr pointing to it is destroyed.