SDL (Simple MediaDirect Layer) trying to scale my sprite (character) - c++

Question

I am just trying to scale (make bigger proportionally) my character based on windows weight and height. How can I do that?
I tried SDL_BlitScaled(newsurface, NULL, screen, NULL); but it did not work.
My code:
SDL_Surface* screen = SDL_GetWindowSurface(win);
SDL_Surface* mySprite = IMG_Load( SPRITE_PNG_PATH);
SDL_Rect rcSprite;
rcSprite.x = 250;
rcSprite.y = 100;
SDL_BlitSurface(mySprite, NULL, screen, &rcSprite);

Answer 1

The best way to accomplish this is to have a middle surface, whose width and height are your game's native resolution. You then render the entire frame to this surface, and render that surface to the window using the SDL_BlitScaled function.
For example, if you want your native resolution to be 600x400, you would create a 600x400 surface, blit your character and whatever else to that surface, and then finally scaled blit that surface to the window. If you resize your window to 1200x800, everything will look twice as big.
SDL_Surface* screen = SDL_GetWindowSurface(win);
// Create a surface with our native resolution
int NATIVE_WIDTH = 600;
int NATIVE_HEIGHT = 400;
SDL_Surface* frame = SDL_CreateRGBSurface(0, NATIVE_WIDTH, NATIVE_HEIGHT,
screen->format->BitsPerPixel, screen->format->Rmask,
screen->format->Gmask, screen->format->Bmask, screen->format->Amask);
assert(frameSurface);
SDL_Surface* mySprite = IMG_Load( SPRITE_PNG_PATH);
SDL_Rect rcSprite;
rcSprite.x = 250;
rcSprite.y = 100;
// Blit everything to the intermediate surface, instead of the screen.
SDL_BlitSurface(mySprite, NULL, frame, &rcSprite);
// Once we've drawn the entire frame, we blit the intermediate surface to
// the window, using BlitScaled to ensure it gets scaled to fit the window.
SDL_BlitScaled(frame, NULL, screen, NULL);