sdl2_ttf RenderText call not working unless in main loop for Mac OS

SDL Development
1

Hi, I seem to be hitting a weird issue on using SDL2_TTF on Mac OS, namely, the TTF_RenderText_Solid call has to happen in the main event loop for rendering to work, even when the text to be rendered stays the same.

Here is a minimum example:

#include <SDL2/SDL.h>
#include <SDL2_ttf/SDL_ttf.h>
#include <stdlib.h>

#include <string>

#define WINDOW_WIDTH 300
#define WINDOW_HEIGHT (WINDOW_WIDTH)

/*
- x, y: upper left corner.
- texture, rect: outputs.
*/
void get_text_and_rect(SDL_Renderer *renderer, int x, int y, std::string text,
                       TTF_Font *font, SDL_Texture **texture, SDL_Rect *rect) {
  int text_width;
  int text_height;
  SDL_Surface *surface;
  SDL_Color textColor = {255, 255, 255, 0};

  surface = TTF_RenderText_Solid(font, text.c_str(), textColor);
  *texture = SDL_CreateTextureFromSurface(renderer, surface);
  text_width = surface->w;
  text_height = surface->h;
  SDL_FreeSurface(surface);
  rect->x = x;
  rect->y = y;
  rect->w = text_width;
  rect->h = text_height;
}

int main(int argc, char **argv) {
  SDL_Event event;
  SDL_Rect rect1, rect2;
  SDL_Renderer *renderer;
  SDL_Texture *texture1, *texture2;
  SDL_Window *window;
  std::string font_path;
  int quit;

  font_path = "path-to-font.ttf";

  /* Inint TTF. */
  SDL_Init(SDL_INIT_TIMER | SDL_INIT_VIDEO);
  SDL_CreateWindowAndRenderer(WINDOW_WIDTH, WINDOW_WIDTH, 0, &window,
                              &renderer);
  TTF_Init();
  TTF_Font *font = TTF_OpenFont(font_path.c_str(), 24);
  if (font == NULL) {
    fprintf(stderr, "error: font not found\n");
    exit(EXIT_FAILURE);
  }

  quit = 0;
  // Does not work unless these two lines below are in the main while loop
  get_text_and_rect(renderer, 0, 0, "hello", font, &texture1, &rect1);
  get_text_and_rect(renderer, 0, rect1.y + rect1.h, "world", font, &texture2,
                    &rect2);

  while (!quit) {
    while (SDL_PollEvent(&event) == 1) {
      if (event.type == SDL_QUIT) {
        quit = 1;
      }
    }
    SDL_SetRenderDrawColor(renderer, 0, 0, 0, 0);
    SDL_RenderClear(renderer);

   // Would work if the get_text_and_rect calls are placed here

    /* Use TTF textures. */
    SDL_RenderCopy(renderer, texture1, NULL, &rect1);
    SDL_RenderCopy(renderer, texture2, NULL, &rect2);

    SDL_RenderPresent(renderer);
  }

  /* Deinit TTF. */
  SDL_DestroyTexture(texture1);
  SDL_DestroyTexture(texture2);
  TTF_Quit();

  SDL_DestroyRenderer(renderer);
  SDL_DestroyWindow(window);
  SDL_Quit();
  return EXIT_SUCCESS;
}

As commented in code, I have to move the get_text_and_rect call inside the main event loop for it to render the text. This seems to not be the case from all the sdl tutorials I’ve read (for example: LazyFoo’s tutorial). While I could work around by placing them in the main loop, it is very inefficient as the text does not change.

Is this a known issue? I’m on BigSur 11.2.3 and SDL_ttf 2.0.15

Thanks!