From 29baefe85ac8a0a1c33fd265459a3c72c4557943 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Mon, 15 Jan 2018 21:40:53 -0500
Subject: [PATCH] handle controller axis events

---
 sdl-game-controller.cc | 48 ++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 46 insertions(+), 2 deletions(-)

diff --git a/sdl-game-controller.cc b/sdl-game-controller.cc
index 2b960c5..8849aed 100644
--- a/sdl-game-controller.cc
+++ b/sdl-game-controller.cc
@@ -28,6 +28,14 @@ GLfloat colors[][4] = {
     {1.0, 1.0, 0.0, 1.0},
     {0.2, 0.2, 1.0, 1.0},
 };
+float movement[2];
+static SDL_Event UpdateEvent;
+
+static Uint32 UpdateCallback(Uint32 interval, void * param)
+{
+    SDL_PushEvent(&UpdateEvent);
+    return interval;
+}
 
 bool init(void)
 {
@@ -77,9 +85,26 @@ void display(SDL_Window * window)
     SDL_GL_SwapWindow(window);
 }
 
+void process_movement(int axis, float amount)
+{
+    position[axis] += amount;
+    if (position[axis] < -1.0)
+        position[axis] = -1.0;
+    else if (position[axis] > 1.0)
+        position[axis] = 1.0;
+}
+
+void process_movements()
+{
+    for (int i = 0; i <= 1; i++)
+    {
+        process_movement(i, movement[i] * 25.0 / 1000.0);
+    }
+}
+
 int main(int argc, char *argv[])
 {
-    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_JOYSTICK | SDL_INIT_GAMECONTROLLER | SDL_INIT_EVENTS))
+    if (SDL_Init(SDL_INIT_TIMER | SDL_INIT_VIDEO | SDL_INIT_JOYSTICK | SDL_INIT_GAMECONTROLLER | SDL_INIT_EVENTS))
     {
         printf("Failed to initialize SDL!\n");
         return 1;
@@ -119,6 +144,10 @@ int main(int argc, char *argv[])
         return 2;
     }
 
+    UpdateEvent.type = SDL_USEREVENT;
+    UpdateEvent.user.code = 0;
+    SDL_AddTimer(25, UpdateCallback, NULL);
+
     int n_joysticks = SDL_NumJoysticks();
     std::list<SDL_GameController *> game_controllers;
     for (int i = 0; i < n_joysticks; i++)
@@ -152,12 +181,27 @@ int main(int argc, char *argv[])
             }
             else if (event.type == SDL_CONTROLLERAXISMOTION)
             {
-                std::cerr << "motion!" << std::endl;
+                if (event.caxis.axis == SDL_CONTROLLER_AXIS_LEFTX)
+                {
+                    movement[0] = event.caxis.value / 32768.0;
+                    if (fabsf(movement[0]) < 0.02)
+                        movement[0] = 0.0;
+                }
+                else if (event.caxis.axis == SDL_CONTROLLER_AXIS_LEFTY)
+                {
+                    movement[1] = -event.caxis.value / 32768.0;
+                    if (fabsf(movement[1]) < 0.02)
+                        movement[1] = 0.0;
+                }
             }
             else if (event.type == SDL_CONTROLLERBUTTONDOWN)
             {
                 std::cerr << "button!" << std::endl;
             }
+            else if (event.type == SDL_USEREVENT)
+            {
+                process_movements();
+            }
         }
         if (exit)
             break;