add WIP gamepad example

Makefile

@@ -5,6 +5,7 @@ example:
 	make opengl
 	make mac-load
 	make hello-world
+	make gamepad
 	make save-file
 	make button
 	make checkbox
@@ -38,6 +39,8 @@ mac-load:
 	gcc $(ARGS) examples/general/mac-load.c -I./ -framework Cocoa -o mac-load
 hello-world:
 	gcc $(ARGS) examples/general/hello-world.c -I./ -framework Cocoa -o hello-world
+gamepad:
+	gcc $(ARGS) examples/general/gamepad.c -I./ -framework Cocoa -o gamepad
 events:
 	gcc $(ARGS) examples/general/events.c -I./ -framework Cocoa -o events
 

examples/general/gamepad.c

@@ -0,0 +1,92 @@
+#define GL_SILENCE_DEPRECATION
+#define SILICON_IMPLEMENTATION
+#include <silicon.h>
+
+#include <IOKit/hid/IOHIDManager.h>
+
+NSApplication* NSApp; 
+
+void Handle_DeviceMatchingCallback(void *context, IOReturn result, void *sender, IOHIDDeviceRef device);
+void Handle_DeviceRemovalCallback(void *context, IOReturn result, void *sender, IOHIDDeviceRef device);
+void Handle_InputValueCallback(void *context, IOReturn result, void *sender, IOHIDValueRef value);
+
+typedef struct {
+    IOHIDManagerRef hidManager;
+} AppDelegate;
+
+void applicationDidFinishLaunching(AppDelegate *appDelegate) {
+    appDelegate->hidManager = IOHIDManagerCreate(kCFAllocatorDefault, kIOHIDOptionsTypeNone);
+
+    CFDictionaryRef criteria = CFDictionaryCreate(kCFAllocatorDefault, 
+        (const void *[]){ CFSTR(kIOHIDDeviceUsagePageKey), CFSTR(kIOHIDDeviceUsageKey) },
+        (const void *[]){ CFNumberCreate(kCFAllocatorDefault, kCFNumberIntType, &(int){kHIDPage_GenericDesktop}), 
+                          CFNumberCreate(kCFAllocatorDefault, kCFNumberIntType, &(int){kHIDUsage_GD_GamePad}) },
+        2, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
+
+    IOHIDManagerSetDeviceMatching(appDelegate->hidManager, criteria);
+    CFRelease(criteria);
+
+    IOHIDManagerRegisterDeviceMatchingCallback(appDelegate->hidManager, Handle_DeviceMatchingCallback, appDelegate);
+    IOHIDManagerRegisterDeviceRemovalCallback(appDelegate->hidManager, Handle_DeviceRemovalCallback, appDelegate);
+    IOHIDManagerRegisterInputValueCallback(appDelegate->hidManager, Handle_InputValueCallback, appDelegate);
+
+    IOHIDManagerScheduleWithRunLoop(appDelegate->hidManager, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode);
+    IOHIDManagerOpen(appDelegate->hidManager, kIOHIDOptionsTypeNone);
+}
+
+void applicationWillTerminate(AppDelegate *appDelegate) {
+    IOHIDManagerClose(appDelegate->hidManager, kIOHIDOptionsTypeNone);
+    CFRelease(appDelegate->hidManager);
+}
+
+void Handle_DeviceMatchingCallback(void *context, IOReturn result, void *sender, IOHIDDeviceRef device) {
+    printf("Gamepad connected: %p\n", device);
+}
+
+void Handle_DeviceRemovalCallback(void *context, IOReturn result, void *sender, IOHIDDeviceRef device) {
+    printf("Gamepad disconnected: %p\n", device);
+}
+
+void Handle_InputValueCallback(void *context, IOReturn result, void *sender, IOHIDValueRef value) {
+    IOHIDElementRef element = IOHIDValueGetElement(value);
+    uint32_t usagePage = IOHIDElementGetUsagePage(element);
+    uint32_t usage = IOHIDElementGetUsage(element);
+    CFIndex logicalValue = IOHIDValueGetIntegerValue(value);
+
+    if (usagePage == kHIDPage_Button) {
+        printf("Button %d: %ld\n", usage, logicalValue);
+    } else if (usagePage == kHIDPage_GenericDesktop) {
+        switch (usage) {
+            case kHIDUsage_GD_X:
+                printf("X Axis: %ld\n", logicalValue);
+                break;
+            case kHIDUsage_GD_Y:
+                printf("Y Axis: %ld\n", logicalValue);
+                break;
+            case kHIDUsage_GD_Z:
+                printf("Z Axis: %ld\n", logicalValue);
+                break;
+            case kHIDUsage_GD_Rx:
+                printf("Rx Axis: %ld\n", logicalValue);
+                break;
+            case kHIDUsage_GD_Ry:
+                printf("Ry Axis: %ld\n", logicalValue);
+                break;
+            case kHIDUsage_GD_Rz:
+                printf("Rz Axis: %ld\n", logicalValue);
+                break;
+            default:
+                break;
+        }
+    }
+}
+
+int main(int argc, const char * argv[]) {
+    AppDelegate appDelegate;
+    applicationDidFinishLaunching(&appDelegate);
+    NSApp = NSApplication_sharedApplication();
+
+    NSApplication_run(NSApp);
+    applicationWillTerminate(&appDelegate);
+    return 0;
+}