A small SDL start field example.

starfield_cpp_main.cpp

#include <iostream>
#include <stdlib.h>
#include <SDL.h>
#include <experimental/random>
#include <vector>

const int WIDTH = 1360, HEIGHT = 760;
const int H_WIDTH = WIDTH / 2;
const int H_HEIGHT = HEIGHT / 2;
const int STARS_COUNT = 5000;
float speed = 0.1;
float radius_delta = 0.001;
Uint32 fps_lasttime = SDL_GetTicks();
Uint32 fps_frames = 0;

// struct Star ...
struct Star {
   float x, y, z, radius, brightness, viewX, viewY;
   
   Star() { newStar(); }
   
   void newStar() {
	  x = viewX = std::experimental::randint(0, WIDTH) - H_WIDTH;
	  y = viewY = std::experimental::randint(0, HEIGHT) - H_HEIGHT;
	  z = 256;
	  brightness = 0.0;
	  radius = 1.0;
   }
   
   bool isOffScreen() {
	  return z <= 0 || viewX <= -H_WIDTH || viewY <= -H_HEIGHT || viewX >= H_WIDTH || viewY >= H_HEIGHT;
   }
   
   void processStar() {
	  viewX = std::round(x * 256 / z);
	  viewY = std::round(y * 256 / z);
	  z -= speed;
	  radius += radius_delta;
	  if (isOffScreen()) { newStar(); }
	  if (brightness < 256) { brightness += 0.15; }
   }
};


void setFPStitle(SDL_Window *window) {
    fps_frames++;
    if (fps_lasttime < SDL_GetTicks() - 1000) {
        fps_lasttime = SDL_GetTicks();
        auto title = "C++ SDL window: " + std::to_string(fps_frames) + " FPS";
        fps_frames = 0;
        SDL_SetWindowTitle(window, title.c_str());
    }
}

int SDL_RenderDrawCircle(SDL_Renderer * renderer, int x, int y, int radius) {
   int offsetx, offsety, d;
   int status;
   
   offsetx = 0;
   offsety = radius;
   d = radius -1;
   status = 0;
   
   while (offsety >= offsetx) {
	  status += SDL_RenderDrawPoint(renderer, x + offsetx, y + offsety);
	  status += SDL_RenderDrawPoint(renderer, x + offsety, y + offsetx);
	  status += SDL_RenderDrawPoint(renderer, x - offsetx, y + offsety);
	  status += SDL_RenderDrawPoint(renderer, x - offsety, y + offsetx);
	  status += SDL_RenderDrawPoint(renderer, x + offsetx, y - offsety);
	  status += SDL_RenderDrawPoint(renderer, x + offsety, y - offsetx);
	  status += SDL_RenderDrawPoint(renderer, x - offsetx, y - offsety);
	  status += SDL_RenderDrawPoint(renderer, x - offsety, y - offsetx);
	  
	  if (status < 0) {
		 status = -1;
		 break;
	  }
	  
	  if (d >= 2*offsetx) {
		 d -= 2*offsetx + 1;
		 offsetx +=1;
	  }
	  else if (d < 2 * (radius - offsety)) {
		 d += 2 * offsety - 1;
		 offsety -= 1;
	  }
	  else {
		 d += 2 * (offsety - offsetx - 1);
		 offsety -= 1;
		 offsetx += 1;
	  }
   }
   
   return status;
}

int SDL_RenderFillCircle(SDL_Renderer * renderer, int x, int y, int radius) {
   int offsetx, offsety, d;
   int status;
   
   offsetx = 0;
   offsety = radius;
   d = radius -1;
   status = 0;
   
   while (offsety >= offsetx) {
	  status += SDL_RenderDrawLine(renderer, x - offsety, y + offsetx, x + offsety, y + offsetx);
	  status += SDL_RenderDrawLine(renderer, x - offsetx, y + offsety, x + offsetx, y + offsety);
	  status += SDL_RenderDrawLine(renderer, x - offsetx, y - offsety, x + offsetx, y - offsety);
	  status += SDL_RenderDrawLine(renderer, x - offsety, y - offsetx, x + offsety, y - offsetx);	  
	  if (status < 0) {
		 status = -1;
		 break;
	  }	  
	  if (d >= 2*offsetx) {
		 d -= 2*offsetx + 1;
		 offsetx +=1;
	  }
	  else if (d < 2 * (radius - offsety)) {
		 d += 2 * offsety - 1;
		 offsety -= 1;
	  }
	  else {
		 d += 2 * (offsety - offsetx - 1);
		 offsety -= 1;
		 offsetx += 1;
	  }
   }
   
   return status;
}

int main(int argc, char *argv[]) {
   SDL_Init(SDL_INIT_EVERYTHING);
   
   SDL_Window *window = SDL_CreateWindow("C++ SDL window", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
										 WIDTH, HEIGHT, SDL_WINDOW_ALLOW_HIGHDPI);
   
   if (window == NULL) {
	  std::cout << "Could not create window: " << SDL_GetError() << std::endl;
	  return 1;
   }
   
   SDL_Renderer *renderer = SDL_CreateRenderer(window, -1, 0);
   if (renderer == NULL) {
	  std::cout << "Could not init renderer: " << SDL_GetError() << std::endl;
	  return 1;
   }
   
   // SDL initialization ...
   SDL_Event windowEvent;
   std::vector<Star> stars(STARS_COUNT, Star());
   
   while (true) {
	  if (SDL_PollEvent(&windowEvent)) {
		 if (windowEvent.type == SDL_QUIT) break;
	  }
	  
	  setFPStitle(window);
	  
	  SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
	  SDL_RenderClear(renderer);
      
	  for (int i = 0; i < STARS_COUNT; i++) {
		 Star *star = &stars[i];
		 star->processStar();
		 SDL_SetRenderDrawColor(renderer, star->brightness, star->brightness, star->brightness, 255);
		 int x = star->viewX + H_WIDTH;
		 int y = star->viewY + H_HEIGHT;
		 SDL_RenderFillCircle(renderer, x, y, std::round(star->radius));
	  }
	  SDL_RenderPresent(renderer);
   }
   
   SDL_DestroyRenderer(renderer);
   SDL_DestroyWindow(window);
   SDL_Quit();
   
   return EXIT_SUCCESS;
}