Drawing SDL_Surface from another class - c++

Question

So I have three classes Application, DrawMgr and Cube. In Application.cpp is my main loop in which I call DrawMgr::DrawCube in which I call Cube::Draw.
Application.cpp
while (!quit)
{
//Draw Background
gDrawMgr.DrawBackground();
gDrawMgr.DrawCube();
//UpdateScreen
gDrawMgr.UpdateScreen();
//Handle events on queue
while (SDL_PollEvent(&e) != 0)
{
//User requests quit
if (e.type == SDL_QUIT || e.key.keysym.sym == SDLK_ESCAPE)
{
quit = true;
}
}
}
DrawMgr.cpp
SDL_Surface* screenSurface;
void DrawMgr::DrawCube()
{
gCube.Draw(screenSurface);
}
Cube.cpp
void Cube::Draw( SDL_Surface* destination )
{
SDL_Rect offset;
offset.x = 100;
offset.y = 100;
SDL_FillRect(cube, NULL, SDL_MapRGB( cube->format, 0, 0, 0 ) );
SDL_BlitSurface( cube, NULL, destination, &offset);
}
When I run the program, the cube doesn't appear, what am I doing wrong?

Answer 1

Are you sure you're using SDL2.0 ? because things have changed, you need a SDL_Renderer and a SDL_Texture. Seems like you're trying to do it in the SDL 1 way.
In SDL2, to update the screen, we use those calls
SDL_RenderClear(sdlRenderer);
SDL_RenderCopy(sdlRenderer, sdlTexture, NULL, NULL);
SDL_RenderPresent(sdlRenderer);
RenderClear to wipe the screen content.
RenderCopy to draw some texture on it.
RenderPresent to draw the final result on the screen.
Go see the migration guide for more details on the new flow.
https://wiki.libsdl.org/MigrationGuide