Testing metal on my macs. My dear Mac Mini does not support it

test_metal_with_sdl2.c

#include "SDL2.framework/Headers/SDL.h"

#define sdl2_guard(__expr) \
  if ((__expr) != 0) {     \
    fprintf(stderr, "SDL Error: '%s'\n", SDL_GetError()); \
    assert(0); \
  }

#include <assert.h>

// Metal isn't supposed to support pre-GCN AMD graphics cards
// My metal Mini has such AMD HD 6600M. GCN starts with 7000

int main(int argc, char **argv)
{
  sdl2_guard(SDL_Init(SDL_INIT_VIDEO));
  SDL_Window *window = SDL_CreateWindow("metal-test", 20, 20, 500, 500, 0);
  sdl2_guard(window == NULL? -1:0);
  SDL_Renderer *renderer;
  {
    int num_drivers = SDL_GetNumRenderDrivers();
    for (int i = 0; i < num_drivers; i++) {
      SDL_RendererInfo renderer_info;
      sdl2_guard(SDL_GetRenderDriverInfo(i, &renderer_info));
      printf("driver[%d] = SDL_RendererInfo {\n", i);
      printf("  name = \"%s\";\n", renderer_info.name);
      printf("  flags = 0%s%s%s%s;\n",
             renderer_info.flags & SDL_RENDERER_SOFTWARE? " | SDL_RENDERER_SOFTWARE" : "",
             renderer_info.flags & SDL_RENDERER_ACCELERATED? " | SDL_RENDERER_ACCELERATED" : "",
             renderer_info.flags & SDL_RENDERER_PRESENTVSYNC? " | SDL_RENDERER_PRESENTVSYNC" : "",
             renderer_info.flags & SDL_RENDERER_TARGETTEXTURE? " | SDL_RENDERER_TARGETTEXTURE" : "");
      printf("  // ...\n");
      printf("}\n");
      if (0 == strcmp("metal", renderer_info.name)) {
        renderer = SDL_CreateRenderer(window, i, renderer_info.flags);
        sdl2_guard(renderer == NULL? -1:0);
      }
    }
  }

  int must_quit = 0;
  while (!must_quit) {
    SDL_Event event;
    while (SDL_PollEvent(&event) != 0) {
      if (event.type == SDL_QUIT) {
        must_quit = 1;
      }
    }
    SDL_SetRenderDrawColor(renderer, 50, 50, 52, 0);
    SDL_RenderClear(renderer);
    SDL_SetRenderDrawColor(renderer, 40, 80, 12, 255);
    SDL_RenderDrawRect(renderer, &(SDL_Rect){.x = 20, .y = 20, .w = 460, .h = 460 });
    SDL_RenderPresent(renderer);
  }
  
  SDL_Quit();
  return 0;
}