examples/example_apple_metal/main.mm - external/github.com/ocornut/imgui - Git at Google

 // Dear ImGui: standalone example application for OSX + Metal.
 // If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
 // Read online: https://github.com/ocornut/imgui/tree/master/docs

 #import <Foundation/Foundation.h>

 #if TARGET_OS_OSX
 #import <Cocoa/Cocoa.h>
 #else
 #import <UIKit/UIKit.h>
 #endif

 #import <Metal/Metal.h>
 #import <MetalKit/MetalKit.h>

 #include "imgui.h"
 #include "imgui_impl_metal.h"
 #if TARGET_OS_OSX
 #include "imgui_impl_osx.h"
 @interface AppViewController : NSViewController
 @end
 #else
 @interface AppViewController : UIViewController
 @end
 #endif

 @interface AppViewController () <MTKViewDelegate>
 @property (nonatomic, readonly) MTKView *mtkView;
 @property (nonatomic, strong) id <MTLDevice> device;
 @property (nonatomic, strong) id <MTLCommandQueue> commandQueue;
 @end

 //-----------------------------------------------------------------------------------
 // AppViewController
 //-----------------------------------------------------------------------------------

 @implementation AppViewController

 -(instancetype)initWithNibName:(nullable NSString *)nibNameOrNil bundle:(nullable NSBundle *)nibBundleOrNil
 {
     self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];

     _device = MTLCreateSystemDefaultDevice();
     _commandQueue = [_device newCommandQueue];

     if (!self.device)
     {
         NSLog(@"Metal is not supported");
         abort();
     }

     // Setup Dear ImGui context
     // FIXME: This example doesn't have proper cleanup...
     IMGUI_CHECKVERSION();
     ImGui::CreateContext();
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     //io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     //io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls

     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsClassic();

     // Setup Renderer backend
     ImGui_ImplMetal_Init(_device);

     // Load Fonts
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
     // - If the file cannot be loaded, the function will return NULL. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
     // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Read 'docs/FONTS.txt' for more instructions and details.
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
     //io.Fonts->AddFontDefault();
     //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
     //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
     //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
     //io.Fonts->AddFontFromFileTTF("../../misc/fonts/ProggyTiny.ttf", 10.0f);
     //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, NULL, io.Fonts->GetGlyphRangesJapanese());
     //IM_ASSERT(font != NULL);

     return self;
 }

 -(MTKView *)mtkView
 {
     return (MTKView *)self.view;
 }

 -(void)loadView
 {
     self.view = [[MTKView alloc] initWithFrame:CGRectMake(0, 0, 1200, 720)];
 }

 -(void)viewDidLoad
 {
     [super viewDidLoad];

     self.mtkView.device = self.device;
     self.mtkView.delegate = self;

 #if TARGET_OS_OSX
     // Add a tracking area in order to receive mouse events whenever the mouse is within the bounds of our view
     NSTrackingArea *trackingArea = [[NSTrackingArea alloc] initWithRect:NSZeroRect
                                                                 options:NSTrackingMouseMoved | NSTrackingInVisibleRect | NSTrackingActiveAlways
                                                                   owner:self
                                                                userInfo:nil];
     [self.view addTrackingArea:trackingArea];

     // If we want to receive key events, we either need to be in the responder chain of the key view,
     // or else we can install a local monitor. The consequence of this heavy-handed approach is that
     // we receive events for all controls, not just Dear ImGui widgets. If we had native controls in our
     // window, we'd want to be much more careful than just ingesting the complete event stream.
     // To match the behavior of other backends, we pass every event down to the OS.
     NSEventMask eventMask = NSEventMaskKeyDown | NSEventMaskKeyUp | NSEventMaskFlagsChanged;
     [NSEvent addLocalMonitorForEventsMatchingMask:eventMask handler:^NSEvent * _Nullable(NSEvent *event)
     {
         ImGui_ImplOSX_HandleEvent(event, self.view);
         return event;
     }];

     ImGui_ImplOSX_Init(self.view);

 #endif
 }

 -(void)drawInMTKView:(MTKView*)view
 {
     ImGuiIO& io = ImGui::GetIO();
     io.DisplaySize.x = view.bounds.size.width;
     io.DisplaySize.y = view.bounds.size.height;

 #if TARGET_OS_OSX
     CGFloat framebufferScale = view.window.screen.backingScaleFactor ?: NSScreen.mainScreen.backingScaleFactor;
 #else
     CGFloat framebufferScale = view.window.screen.scale ?: UIScreen.mainScreen.scale;
 #endif
     io.DisplayFramebufferScale = ImVec2(framebufferScale, framebufferScale);

     io.DeltaTime = 1 / float(view.preferredFramesPerSecond ?: 60);

     id<MTLCommandBuffer> commandBuffer = [self.commandQueue commandBuffer];

     MTLRenderPassDescriptor* renderPassDescriptor = view.currentRenderPassDescriptor;
     if (renderPassDescriptor == nil)
     {
         [commandBuffer commit];
 		return;
     }

     // Start the Dear ImGui frame
     ImGui_ImplMetal_NewFrame(renderPassDescriptor);
 #if TARGET_OS_OSX
     ImGui_ImplOSX_NewFrame(view);
 #endif
     ImGui::NewFrame();

     // Our state (make them static = more or less global) as a convenience to keep the example terse.
     static bool show_demo_window = true;
     static bool show_another_window = false;
     static ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);

     // 1. Show the big demo window (Most of the sample code is in ImGui::ShowDemoWindow()! You can browse its code to learn more about Dear ImGui!).
     if (show_demo_window)
         ImGui::ShowDemoWindow(&show_demo_window);

     // 2. Show a simple window that we create ourselves. We use a Begin/End pair to created a named window.
     {
         static float f = 0.0f;
         static int counter = 0;

         ImGui::Begin("Hello, world!");                          // Create a window called "Hello, world!" and append into it.

         ImGui::Text("This is some useful text.");               // Display some text (you can use a format strings too)
         ImGui::Checkbox("Demo Window", &show_demo_window);      // Edit bools storing our window open/close state
         ImGui::Checkbox("Another Window", &show_another_window);

         ImGui::SliderFloat("float", &f, 0.0f, 1.0f);            // Edit 1 float using a slider from 0.0f to 1.0f
         ImGui::ColorEdit3("clear color", (float*)&clear_color); // Edit 3 floats representing a color

         if (ImGui::Button("Button"))                            // Buttons return true when clicked (most widgets return true when edited/activated)
             counter++;
         ImGui::SameLine();
         ImGui::Text("counter = %d", counter);

         ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / ImGui::GetIO().Framerate, ImGui::GetIO().Framerate);
         ImGui::End();
     }

     // 3. Show another simple window.
     if (show_another_window)
     {
         ImGui::Begin("Another Window", &show_another_window);   // Pass a pointer to our bool variable (the window will have a closing button that will clear the bool when clicked)
         ImGui::Text("Hello from another window!");
         if (ImGui::Button("Close Me"))
             show_another_window = false;
         ImGui::End();
     }

     // Rendering
     ImGui::Render();
     ImDrawData* draw_data = ImGui::GetDrawData();

     renderPassDescriptor.colorAttachments[0].clearColor = MTLClearColorMake(clear_color.x * clear_color.w, clear_color.y * clear_color.w, clear_color.z * clear_color.w, clear_color.w);
     id <MTLRenderCommandEncoder> renderEncoder = [commandBuffer renderCommandEncoderWithDescriptor:renderPassDescriptor];
     [renderEncoder pushDebugGroup:@"Dear ImGui rendering"];
     ImGui_ImplMetal_RenderDrawData(draw_data, commandBuffer, renderEncoder);
     [renderEncoder popDebugGroup];
     [renderEncoder endEncoding];

 	// Present
     [commandBuffer presentDrawable:view.currentDrawable];
     [commandBuffer commit];
 }

 -(void)mtkView:(MTKView*)view drawableSizeWillChange:(CGSize)size
 {
 }

 //-----------------------------------------------------------------------------------
 // Input processing
 //-----------------------------------------------------------------------------------

 #if TARGET_OS_OSX

 // Forward Mouse/Keyboard events to Dear ImGui OSX backend.
 // Other events are registered via addLocalMonitorForEventsMatchingMask()
 -(void)mouseDown:(NSEvent *)event           { ImGui_ImplOSX_HandleEvent(event, self.view); }
 -(void)rightMouseDown:(NSEvent *)event      { ImGui_ImplOSX_HandleEvent(event, self.view); }
 -(void)otherMouseDown:(NSEvent *)event      { ImGui_ImplOSX_HandleEvent(event, self.view); }
 -(void)mouseUp:(NSEvent *)event             { ImGui_ImplOSX_HandleEvent(event, self.view); }
 -(void)rightMouseUp:(NSEvent *)event        { ImGui_ImplOSX_HandleEvent(event, self.view); }
 -(void)otherMouseUp:(NSEvent *)event        { ImGui_ImplOSX_HandleEvent(event, self.view); }
 -(void)mouseMoved:(NSEvent *)event          { ImGui_ImplOSX_HandleEvent(event, self.view); }
 -(void)mouseDragged:(NSEvent *)event        { ImGui_ImplOSX_HandleEvent(event, self.view); }
 -(void)rightMouseMoved:(NSEvent *)event     { ImGui_ImplOSX_HandleEvent(event, self.view); }
 -(void)rightMouseDragged:(NSEvent *)event   { ImGui_ImplOSX_HandleEvent(event, self.view); }
 -(void)otherMouseMoved:(NSEvent *)event     { ImGui_ImplOSX_HandleEvent(event, self.view); }
 -(void)otherMouseDragged:(NSEvent *)event   { ImGui_ImplOSX_HandleEvent(event, self.view); }
 -(void)scrollWheel:(NSEvent *)event         { ImGui_ImplOSX_HandleEvent(event, self.view); }

 #else

 // This touch mapping is super cheesy/hacky. We treat any touch on the screen
 // as if it were a depressed left mouse button, and we don't bother handling
 // multitouch correctly at all. This causes the "cursor" to behave very erratically
 // when there are multiple active touches. But for demo purposes, single-touch
 // interaction actually works surprisingly well.
 -(void)updateIOWithTouchEvent:(UIEvent *)event
 {
     UITouch *anyTouch = event.allTouches.anyObject;
     CGPoint touchLocation = [anyTouch locationInView:self.view];
     ImGuiIO &io = ImGui::GetIO();
     io.MousePos = ImVec2(touchLocation.x, touchLocation.y);

     BOOL hasActiveTouch = NO;
     for (UITouch *touch in event.allTouches)
     {
         if (touch.phase != UITouchPhaseEnded && touch.phase != UITouchPhaseCancelled)
         {
             hasActiveTouch = YES;
             break;
         }
     }
     io.MouseDown[0] = hasActiveTouch;
 }

 -(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event      { [self updateIOWithTouchEvent:event]; }
 -(void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event      { [self updateIOWithTouchEvent:event]; }
 -(void)touchesCancelled:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event  { [self updateIOWithTouchEvent:event]; }
 -(void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event      { [self updateIOWithTouchEvent:event]; }

 #endif

 @end

 //-----------------------------------------------------------------------------------
 // AppDelegate
 //-----------------------------------------------------------------------------------

 #if TARGET_OS_OSX

 @interface AppDelegate : NSObject <NSApplicationDelegate>
 @property (nonatomic, strong) NSWindow *window;
 @end

 @implementation AppDelegate

 -(BOOL)applicationShouldTerminateAfterLastWindowClosed:(NSApplication *)sender
 {
     return YES;
 }

 -(instancetype)init
 {
     if (self = [super init])
     {
         NSViewController *rootViewController = [[AppViewController alloc] initWithNibName:nil bundle:nil];
         self.window = [[NSWindow alloc] initWithContentRect:NSZeroRect
                                                   styleMask:NSWindowStyleMaskTitled | NSWindowStyleMaskClosable | NSWindowStyleMaskResizable | NSWindowStyleMaskMiniaturizable
                                                     backing:NSBackingStoreBuffered
                                                       defer:NO];
         self.window.contentViewController = rootViewController;
         [self.window orderFront:self];
         [self.window center];
         [self.window becomeKeyWindow];
     }
     return self;
 }

 @end

 #else

 @interface AppDelegate : UIResponder <UIApplicationDelegate>
 @property (strong, nonatomic) UIWindow *window;
 @end

 @implementation AppDelegate

 -(BOOL)application:(UIApplication *)application
     didFinishLaunchingWithOptions:(NSDictionary<UIApplicationLaunchOptionsKey,id> *)launchOptions
 {
     UIViewController *rootViewController = [[AppViewController alloc] init];
     self.window = [[UIWindow alloc] initWithFrame:UIScreen.mainScreen.bounds];
     self.window.rootViewController = rootViewController;
     [self.window makeKeyAndVisible];
     return YES;
 }

 @end

 #endif

 //-----------------------------------------------------------------------------------
 // Application main() function
 //-----------------------------------------------------------------------------------

 #if TARGET_OS_OSX

 int main(int argc, const char * argv[])
 {
     return NSApplicationMain(argc, argv);
 }

 #else

 int main(int argc, char * argv[])
 {
     @autoreleasepool
     {
         return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
     }
 }

 #endif
	// Dear ImGui: standalone example application for OSX + Metal.
	// If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
	// Read online: https://github.com/ocornut/imgui/tree/master/docs

	#import <Foundation/Foundation.h>

	#if TARGET_OS_OSX
	#import <Cocoa/Cocoa.h>
	#else
	#import <UIKit/UIKit.h>
	#endif

	#import <Metal/Metal.h>
	#import <MetalKit/MetalKit.h>

	#include "imgui.h"
	#include "imgui_impl_metal.h"
	#if TARGET_OS_OSX
	#include "imgui_impl_osx.h"
	@interface AppViewController : NSViewController
	@end
	#else
	@interface AppViewController : UIViewController
	@end
	#endif

	@interface AppViewController () <MTKViewDelegate>
	@property (nonatomic, readonly) MTKView *mtkView;
	@property (nonatomic, strong) id <MTLDevice> device;
	@property (nonatomic, strong) id <MTLCommandQueue> commandQueue;
	@end

	//-----------------------------------------------------------------------------------
	// AppViewController
	//-----------------------------------------------------------------------------------

	@implementation AppViewController

	-(instancetype)initWithNibName:(nullable NSString )nibNameOrNil bundle:(nullable NSBundle )nibBundleOrNil
	{
	self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];

	_device = MTLCreateSystemDefaultDevice();
	_commandQueue = [_device newCommandQueue];

	if (!self.device)
	{
	NSLog(@"Metal is not supported");
	abort();
	}

	// Setup Dear ImGui context
	// FIXME: This example doesn't have proper cleanup...
	IMGUI_CHECKVERSION();
	ImGui::CreateContext();
	ImGuiIO& io = ImGui::GetIO(); (void)io;
	//io.ConfigFlags \|= ImGuiConfigFlags_NavEnableKeyboard; // Enable Keyboard Controls
	//io.ConfigFlags \|= ImGuiConfigFlags_NavEnableGamepad; // Enable Gamepad Controls

	// Setup Dear ImGui style
	ImGui::StyleColorsDark();
	//ImGui::StyleColorsClassic();

	// Setup Renderer backend
	ImGui_ImplMetal_Init(_device);

	// Load Fonts
	// - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
	// - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
	// - If the file cannot be loaded, the function will return NULL. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
	// - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
	// - Read 'docs/FONTS.txt' for more instructions and details.
	// - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
	//io.Fonts->AddFontDefault();
	//io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
	//io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
	//io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
	//io.Fonts->AddFontFromFileTTF("../../misc/fonts/ProggyTiny.ttf", 10.0f);
	//ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, NULL, io.Fonts->GetGlyphRangesJapanese());
	//IM_ASSERT(font != NULL);

	return self;
	}

	-(MTKView *)mtkView
	{
	return (MTKView *)self.view;
	}

	-(void)loadView
	{
	self.view = [[MTKView alloc] initWithFrame:CGRectMake(0, 0, 1200, 720)];
	}

	-(void)viewDidLoad
	{
	[super viewDidLoad];

	self.mtkView.device = self.device;
	self.mtkView.delegate = self;

	#if TARGET_OS_OSX
	// Add a tracking area in order to receive mouse events whenever the mouse is within the bounds of our view
	NSTrackingArea *trackingArea = [[NSTrackingArea alloc] initWithRect:NSZeroRect
	options:NSTrackingMouseMoved \| NSTrackingInVisibleRect \| NSTrackingActiveAlways
	owner:self
	userInfo:nil];
	[self.view addTrackingArea:trackingArea];

	// If we want to receive key events, we either need to be in the responder chain of the key view,
	// or else we can install a local monitor. The consequence of this heavy-handed approach is that
	// we receive events for all controls, not just Dear ImGui widgets. If we had native controls in our
	// window, we'd want to be much more careful than just ingesting the complete event stream.
	// To match the behavior of other backends, we pass every event down to the OS.
	NSEventMask eventMask = NSEventMaskKeyDown \| NSEventMaskKeyUp \| NSEventMaskFlagsChanged;
	[NSEvent addLocalMonitorForEventsMatchingMask:eventMask handler:^NSEvent * _Nullable(NSEvent *event)
	{
	ImGui_ImplOSX_HandleEvent(event, self.view);
	return event;
	}];

	ImGui_ImplOSX_Init(self.view);

	#endif
	}

	-(void)drawInMTKView:(MTKView*)view
	{
	ImGuiIO& io = ImGui::GetIO();
	io.DisplaySize.x = view.bounds.size.width;
	io.DisplaySize.y = view.bounds.size.height;

	#if TARGET_OS_OSX
	CGFloat framebufferScale = view.window.screen.backingScaleFactor ?: NSScreen.mainScreen.backingScaleFactor;
	#else
	CGFloat framebufferScale = view.window.screen.scale ?: UIScreen.mainScreen.scale;
	#endif
	io.DisplayFramebufferScale = ImVec2(framebufferScale, framebufferScale);

	io.DeltaTime = 1 / float(view.preferredFramesPerSecond ?: 60);

	id<MTLCommandBuffer> commandBuffer = [self.commandQueue commandBuffer];

	MTLRenderPassDescriptor* renderPassDescriptor = view.currentRenderPassDescriptor;
	if (renderPassDescriptor == nil)
	{
	[commandBuffer commit];
	return;
	}

	// Start the Dear ImGui frame
	ImGui_ImplMetal_NewFrame(renderPassDescriptor);
	#if TARGET_OS_OSX
	ImGui_ImplOSX_NewFrame(view);
	#endif
	ImGui::NewFrame();

	// Our state (make them static = more or less global) as a convenience to keep the example terse.
	static bool show_demo_window = true;
	static bool show_another_window = false;
	static ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);

	// 1. Show the big demo window (Most of the sample code is in ImGui::ShowDemoWindow()! You can browse its code to learn more about Dear ImGui!).
	if (show_demo_window)
	ImGui::ShowDemoWindow(&show_demo_window);

	// 2. Show a simple window that we create ourselves. We use a Begin/End pair to created a named window.
	{
	static float f = 0.0f;
	static int counter = 0;

	ImGui::Begin("Hello, world!"); // Create a window called "Hello, world!" and append into it.

	ImGui::Text("This is some useful text."); // Display some text (you can use a format strings too)
	ImGui::Checkbox("Demo Window", &show_demo_window); // Edit bools storing our window open/close state
	ImGui::Checkbox("Another Window", &show_another_window);

	ImGui::SliderFloat("float", &f, 0.0f, 1.0f); // Edit 1 float using a slider from 0.0f to 1.0f
	ImGui::ColorEdit3("clear color", (float*)&clear_color); // Edit 3 floats representing a color

	if (ImGui::Button("Button")) // Buttons return true when clicked (most widgets return true when edited/activated)
	counter++;
	ImGui::SameLine();
	ImGui::Text("counter = %d", counter);

	ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / ImGui::GetIO().Framerate, ImGui::GetIO().Framerate);
	ImGui::End();
	}

	// 3. Show another simple window.
	if (show_another_window)
	{
	ImGui::Begin("Another Window", &show_another_window); // Pass a pointer to our bool variable (the window will have a closing button that will clear the bool when clicked)
	ImGui::Text("Hello from another window!");
	if (ImGui::Button("Close Me"))
	show_another_window = false;
	ImGui::End();
	}

	// Rendering
	ImGui::Render();
	ImDrawData* draw_data = ImGui::GetDrawData();

	renderPassDescriptor.colorAttachments[0].clearColor = MTLClearColorMake(clear_color.x * clear_color.w, clear_color.y * clear_color.w, clear_color.z * clear_color.w, clear_color.w);
	id <MTLRenderCommandEncoder> renderEncoder = [commandBuffer renderCommandEncoderWithDescriptor:renderPassDescriptor];
	[renderEncoder pushDebugGroup:@"Dear ImGui rendering"];
	ImGui_ImplMetal_RenderDrawData(draw_data, commandBuffer, renderEncoder);
	[renderEncoder popDebugGroup];
	[renderEncoder endEncoding];

	// Present
	[commandBuffer presentDrawable:view.currentDrawable];
	[commandBuffer commit];
	}

	-(void)mtkView:(MTKView*)view drawableSizeWillChange:(CGSize)size
	{
	}

	//-----------------------------------------------------------------------------------
	// Input processing
	//-----------------------------------------------------------------------------------

	#if TARGET_OS_OSX

	// Forward Mouse/Keyboard events to Dear ImGui OSX backend.
	// Other events are registered via addLocalMonitorForEventsMatchingMask()
	-(void)mouseDown:(NSEvent *)event { ImGui_ImplOSX_HandleEvent(event, self.view); }
	-(void)rightMouseDown:(NSEvent *)event { ImGui_ImplOSX_HandleEvent(event, self.view); }
	-(void)otherMouseDown:(NSEvent *)event { ImGui_ImplOSX_HandleEvent(event, self.view); }
	-(void)mouseUp:(NSEvent *)event { ImGui_ImplOSX_HandleEvent(event, self.view); }
	-(void)rightMouseUp:(NSEvent *)event { ImGui_ImplOSX_HandleEvent(event, self.view); }
	-(void)otherMouseUp:(NSEvent *)event { ImGui_ImplOSX_HandleEvent(event, self.view); }
	-(void)mouseMoved:(NSEvent *)event { ImGui_ImplOSX_HandleEvent(event, self.view); }
	-(void)mouseDragged:(NSEvent *)event { ImGui_ImplOSX_HandleEvent(event, self.view); }
	-(void)rightMouseMoved:(NSEvent *)event { ImGui_ImplOSX_HandleEvent(event, self.view); }
	-(void)rightMouseDragged:(NSEvent *)event { ImGui_ImplOSX_HandleEvent(event, self.view); }
	-(void)otherMouseMoved:(NSEvent *)event { ImGui_ImplOSX_HandleEvent(event, self.view); }
	-(void)otherMouseDragged:(NSEvent *)event { ImGui_ImplOSX_HandleEvent(event, self.view); }
	-(void)scrollWheel:(NSEvent *)event { ImGui_ImplOSX_HandleEvent(event, self.view); }

	#else

	// This touch mapping is super cheesy/hacky. We treat any touch on the screen
	// as if it were a depressed left mouse button, and we don't bother handling
	// multitouch correctly at all. This causes the "cursor" to behave very erratically
	// when there are multiple active touches. But for demo purposes, single-touch
	// interaction actually works surprisingly well.
	-(void)updateIOWithTouchEvent:(UIEvent *)event
	{
	UITouch *anyTouch = event.allTouches.anyObject;
	CGPoint touchLocation = [anyTouch locationInView:self.view];
	ImGuiIO &io = ImGui::GetIO();
	io.MousePos = ImVec2(touchLocation.x, touchLocation.y);

	BOOL hasActiveTouch = NO;
	for (UITouch *touch in event.allTouches)
	{
	if (touch.phase != UITouchPhaseEnded && touch.phase != UITouchPhaseCancelled)
	{
	hasActiveTouch = YES;
	break;
	}
	}
	io.MouseDown[0] = hasActiveTouch;
	}

	-(void)touchesBegan:(NSSet<UITouch > )touches withEvent:(UIEvent *)event { [self updateIOWithTouchEvent:event]; }
	-(void)touchesMoved:(NSSet<UITouch > )touches withEvent:(UIEvent *)event { [self updateIOWithTouchEvent:event]; }
	-(void)touchesCancelled:(NSSet<UITouch > )touches withEvent:(UIEvent *)event { [self updateIOWithTouchEvent:event]; }
	-(void)touchesEnded:(NSSet<UITouch > )touches withEvent:(UIEvent *)event { [self updateIOWithTouchEvent:event]; }

	#endif

	@end

	//-----------------------------------------------------------------------------------
	// AppDelegate
	//-----------------------------------------------------------------------------------

	#if TARGET_OS_OSX

	@interface AppDelegate : NSObject <NSApplicationDelegate>
	@property (nonatomic, strong) NSWindow *window;
	@end

	@implementation AppDelegate

	-(BOOL)applicationShouldTerminateAfterLastWindowClosed:(NSApplication *)sender
	{
	return YES;
	}

	-(instancetype)init
	{
	if (self = [super init])
	{
	NSViewController *rootViewController = [[AppViewController alloc] initWithNibName:nil bundle:nil];
	self.window = [[NSWindow alloc] initWithContentRect:NSZeroRect
	styleMask:NSWindowStyleMaskTitled \| NSWindowStyleMaskClosable \| NSWindowStyleMaskResizable \| NSWindowStyleMaskMiniaturizable
	backing:NSBackingStoreBuffered
	defer:NO];
	self.window.contentViewController = rootViewController;
	[self.window orderFront:self];
	[self.window center];
	[self.window becomeKeyWindow];
	}
	return self;
	}

	@end

	#else

	@interface AppDelegate : UIResponder <UIApplicationDelegate>
	@property (strong, nonatomic) UIWindow *window;
	@end

	@implementation AppDelegate

	-(BOOL)application:(UIApplication *)application
	didFinishLaunchingWithOptions:(NSDictionary<UIApplicationLaunchOptionsKey,id> *)launchOptions
	{
	UIViewController *rootViewController = [[AppViewController alloc] init];
	self.window = [[UIWindow alloc] initWithFrame:UIScreen.mainScreen.bounds];
	self.window.rootViewController = rootViewController;
	[self.window makeKeyAndVisible];
	return YES;
	}

	@end

	#endif

	//-----------------------------------------------------------------------------------
	// Application main() function
	//-----------------------------------------------------------------------------------

	#if TARGET_OS_OSX

	int main(int argc, const char * argv[])
	{
	return NSApplicationMain(argc, argv);
	}

	#else

	int main(int argc, char * argv[])
	{
	@autoreleasepool
	{
	return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
	}
	}

	#endif