open game controller devices and begin receiving events

sdl-game-controller.cc

@@ -3,6 +3,7 @@
 #include "GL3/gl3w.h"
 #include <iostream>
 #include <stdio.h>
+#include <list>
 
 using namespace std;
 
@@ -78,7 +79,7 @@ void display(SDL_Window * window)
 
 int main(int argc, char *argv[])
 {
-    if (SDL_Init(SDL_INIT_VIDEO))
+    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_JOYSTICK | SDL_INIT_GAMECONTROLLER | SDL_INIT_EVENTS))
     {
         printf("Failed to initialize SDL!\n");
         return 1;
@@ -118,6 +119,23 @@ int main(int argc, char *argv[])
         return 2;
     }
 
+    int n_joysticks = SDL_NumJoysticks();
+    std::list<SDL_GameController *> game_controllers;
+    for (int i = 0; i < n_joysticks; i++)
+    {
+        if (SDL_IsGameController(i))
+        {
+            SDL_GameController * game_controller = SDL_GameControllerOpen(i);
+            if (game_controller == nullptr)
+            {
+                cerr << "Failed to open game controller " << i << ": " << SDL_GetError() << endl;
+                return 2;
+            }
+            game_controllers.push_back(game_controller);
+        }
+    }
+    cout << "Found " << n_joysticks << " joystick devices, " << game_controllers.size() << " of which are game controllers" << endl;
+
     display(window);
     SDL_Event event;
     bool exit = false;
@@ -132,11 +150,24 @@ int main(int argc, char *argv[])
                 if (event.key.keysym.sym == SDLK_ESCAPE)
                     exit = true;
             }
+            else if (event.type == SDL_CONTROLLERAXISMOTION)
+            {
+                std::cerr << "motion!" << std::endl;
+            }
+            else if (event.type == SDL_CONTROLLERBUTTONDOWN)
+            {
+                std::cerr << "button!" << std::endl;
+            }
         }
         if (exit)
             break;
         display(window);
     }
 
+    for (auto game_controller : game_controllers)
+    {
+        SDL_GameControllerClose(game_controller);
+    }
+
     return 0;
 }