Simple SDL2/OpenGL example

sdl2_opengl.cpp

// To compile with gcc:  (tested on Ubuntu 14.04 64bit):
//	 g++ sdl2_opengl.cpp -lSDL2 -lGL
// To compile with msvc: (tested on Windows 7 64bit)
//   cl sdl2_opengl.cpp /I C:\sdl2path\include /link C:\path\SDL2.lib C:\path\SDL2main.lib /SUBSYSTEM:CONSOLE /NODEFAULTLIB:libcmtd.lib opengl32.lib

#include <stdio.h>
#include <stdint.h>
#include <assert.h>
#include <SDL2/SDL.h>
#include <SDL2/SDL_opengl.h>
#include <GL/gl.h>

typedef int32_t i32;
typedef uint32_t u32;
typedef int32_t b32;

#define WinWidth 1000
#define WinHeight 1000

int main (int ArgCount, char **Args)
{

  u32 WindowFlags = SDL_WINDOW_OPENGL;
  SDL_Window *Window = SDL_CreateWindow("OpenGL Test", 0, 0, WinWidth, WinHeight, WindowFlags);
  assert(Window);
  SDL_GLContext Context = SDL_GL_CreateContext(Window);
  
  b32 Running = 1;
  b32 FullScreen = 0;
  while (Running)
  {
    SDL_Event Event;
    while (SDL_PollEvent(&Event))
    {
      if (Event.type == SDL_KEYDOWN)
      {
        switch (Event.key.keysym.sym)
        {
          case SDLK_ESCAPE:
            Running = 0;
            break;
          case 'f':
            FullScreen = !FullScreen;
            if (FullScreen)
            {
              SDL_SetWindowFullscreen(Window, WindowFlags | SDL_WINDOW_FULLSCREEN_DESKTOP);
            }
            else
            {
              SDL_SetWindowFullscreen(Window, WindowFlags);
            }
            break;
          default:
            break;
        }
      }
      else if (Event.type == SDL_QUIT)
      {
        Running = 0;
      }
    }

    glViewport(0, 0, WinWidth, WinHeight);
    glClearColor(1.f, 0.f, 1.f, 0.f);
    glClear(GL_COLOR_BUFFER_BIT);

    SDL_GL_SwapWindow(Window);
  }
  return 0;
}

To compile on linux use
g++ sdl2_opengl.cpp -o myprogram -l SDL2 -lGL
./myprogram

Damn I didn't see the very top... ))

Severity	Code	Description	Project	File	Line	Suppression State
Warning	C26812	The enum type 'SDL_bool' is unscoped. Prefer 'enum class' over 'enum' (Enum.3).	Corrode	C:\Users\djdar\source\repos\Corrode\vendor\sdl2\include\SDL_rect.h	102	

:(

fixed on my fork: fullscreen 'f' key and logic, linked SDL2main, booleans for running and fullscreen vars

Hello, does anyone know how to build with -lGL? It's not found, i use -lopengl32 instead. Where does -lGL come from?

Hello, does anyone know how to build with -lGL? It's not found, i use -lopengl32 instead. Where does -lGL come from?

"-lGL" is for linking with OpenGL under Linux, while "-lopengl32" is used under Windows

if you get a 2019 error you do not have to change it from cmd to window application.
i got it to run after having to look it up on StackOverflow. just add this without the quots after the included "#undef main"

or you can do this

You don't need "#include <GL/gl.h>" because it is already included by "#include <SDL2/SDL_opengl.h>" and it also takes care of the problem with OSX.

you didint init SDL, oooof

You don't need "#include <GL/gl.h>" because it is already included by "#include <SDL2/SDL_opengl.h>" and it also takes care of the problem with OSX.

and with:

gcc -lSDL2 -framework OpenGL sdl2_opengl.cpp 

Thanks it work!

I have commented some lines of code that's seemed unnecessary to put in. Tested like this on Debian 11(Linux) it work.

//#include <stdio.h>
//#include <stdint.h>
//#include <assert.h>
#include <SDL2/SDL.h>
#include <SDL2/SDL_opengl.h>
//#include <GL/gl.h>

typedef int32_t i32;
typedef uint32_t u32;
typedef int32_t b32;

#define WinWidth 1000
#define WinHeight 1000

int main (int ArgCount, char **Args)
{

  u32 WindowFlags = SDL_WINDOW_OPENGL;
  SDL_Window *Window = SDL_CreateWindow("OpenGL Test", 0, 0, WinWidth, WinHeight, WindowFlags);
  //assert(Window);
  //SDL_GLContext Context =
  SDL_GL_CreateContext(Window);
...

Thanks it works on win11 !!!