imgui/examples/example_apple_opengl2/main.mm

// ImGui - standalone example application for OSX + OpenGL2, using legacy fixed pipeline
// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.

#include "imgui.h"
#include "../imgui_impl_osx.h"
#include "../imgui_impl_opengl2.h"
#include <stdio.h>
#import <Cocoa/Cocoa.h>
#import <OpenGL/gl.h>
#import <OpenGL/glu.h>

//-----------------------------------------------------------------------------------	
// ImGuiExampleView
//-----------------------------------------------------------------------------------

@interface ImGuiExampleView : NSOpenGLView
{
    NSTimer*    animationTimer;
}
@end

@implementation ImGuiExampleView

-(void)animationTimerFired:(NSTimer*)timer
{
    [self setNeedsDisplay:YES];
}

-(void)prepareOpenGL
{
    [super prepareOpenGL];
	
#ifndef DEBUG
    GLint swapInterval = 1;
    [[self openGLContext] setValues:&swapInterval forParameter:NSOpenGLCPSwapInterval];
    if (swapInterval == 0)
        NSLog(@"Error: Cannot set swap interval.");
#endif
}

-(void)updateAndDrawDemoView
{
	ImGui_ImplOpenGL2_NewFrame();
	ImGui_ImplOSX_NewFrame(self);
    ImGui::NewFrame();

    // Global data for the demo
    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 a simple window.
	// Tip: if we don't call ImGui::Begin()/ImGui::End() the widgets automatically appears in a window called "Debug".
	{
		static float f = 0.0f;
		static int counter = 0;
		ImGui::Text("Hello, world!");                           // Display some text (you can use a format string too)
		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

		ImGui::Checkbox("Demo Window", &show_demo_window);      // Edit bools storing our windows open/close state
		ImGui::Checkbox("Another Window", &show_another_window);

		if (ImGui::Button("Button"))                            // Buttons return true when clicked (NB: 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);
	}

	// 2. Show another simple window. In most cases you will use an explicit Begin/End pair to name your windows.
	if (show_another_window)
	{
		ImGui::Begin("Another Window", &show_another_window);
		ImGui::Text("Hello from another window!");
		if (ImGui::Button("Close Me"))
			show_another_window = false;
		ImGui::End();
	}

	// 3. Show the ImGui demo window. Most of the sample code is in ImGui::ShowDemoWindow(). Read its code to learn more about Dear ImGui!
	if (show_demo_window)
	{
		ImGui::SetNextWindowPos(ImVec2(650, 20), ImGuiCond_FirstUseEver); // Normally user code doesn't need/want to call this because positions are saved in .ini file anyway. Here we just want to make the demo initial state a bit more friendly!
		ImGui::ShowDemoWindow(&show_demo_window);
	}

	// Rendering
	ImGui::Render();
	[[self openGLContext] makeCurrentContext];

    ImGuiIO& io = ImGui::GetIO();
    GLsizei width  = (GLsizei)(io.DisplaySize.x * io.DisplayFramebufferScale.x);
    GLsizei height = (GLsizei)(io.DisplaySize.y * io.DisplayFramebufferScale.y);
    glViewport(0, 0, width, height);

	glClearColor(clear_color.x, clear_color.y, clear_color.z, clear_color.w);
	glClear(GL_COLOR_BUFFER_BIT);
	ImGui_ImplOpenGL2_RenderDrawData(ImGui::GetDrawData());

    // Present
    [[self openGLContext] flushBuffer];
	
    if (!animationTimer)
        animationTimer = [NSTimer scheduledTimerWithTimeInterval:0.017 target:self selector:@selector(animationTimerFired:) userInfo:nil repeats:YES];
}

-(void)reshape
{
    [[self openGLContext] update];
    [self updateAndDrawDemoView];
}

-(void)drawRect:(NSRect)bounds
{
    [self updateAndDrawDemoView];
}

-(BOOL)acceptsFirstResponder
{
    return (YES);
}

-(BOOL)becomeFirstResponder
{
    return (YES);
}

-(BOOL)resignFirstResponder
{
    return (YES);
}

// Flip coordinate system upside down on Y
-(BOOL)isFlipped
{
    return (YES);
}

-(void)dealloc
{
    animationTimer = nil;
}

// Forward Mouse/Keyboard events to dear imgui OSX back-end. It returns true when imgui is expecting to use the event.
-(void)keyUp:(NSEvent *)event           { ImGui_ImplOSX_HandleEvent(event, self); }
-(void)keyDown:(NSEvent *)event         { ImGui_ImplOSX_HandleEvent(event, self); }
-(void)flagsChanged:(NSEvent *)event    { ImGui_ImplOSX_HandleEvent(event, self); }
-(void)mouseDown:(NSEvent *)event       { ImGui_ImplOSX_HandleEvent(event, self); }
-(void)mouseUp:(NSEvent *)event         { ImGui_ImplOSX_HandleEvent(event, self); }
-(void)scrollWheel:(NSEvent *)event     { ImGui_ImplOSX_HandleEvent(event, self); }

@end

//-----------------------------------------------------------------------------------
// ImGuiExampleAppDelegate
//-----------------------------------------------------------------------------------

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

@implementation ImGuiExampleAppDelegate
@synthesize window = _window;

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

-(NSWindow*)window
{
    if (_window != nil)
        return (_window);
	
    NSRect viewRect = NSMakeRect(100.0, 100.0, 100.0 + 1280.0, 100 + 720.0);
	
    _window = [[NSWindow alloc] initWithContentRect:viewRect styleMask:NSWindowStyleMaskTitled|NSWindowStyleMaskMiniaturizable|NSWindowStyleMaskResizable|NSWindowStyleMaskClosable backing:NSBackingStoreBuffered defer:YES];
    [_window setTitle:@"ImGui OSX+OpenGL2 Example"];
    [_window setOpaque:YES];
    [_window makeKeyAndOrderFront:NSApp];
	
    return (_window);
}

-(void)setupMenu
{
	NSMenu* mainMenuBar = [[NSMenu alloc] init];
    NSMenu* appMenu;
    NSMenuItem* menuItem;

    appMenu = [[NSMenu alloc] initWithTitle:@"ImGui OSX+OpenGL2 Example"];
    menuItem = [appMenu addItemWithTitle:@"Quit ImGui OSX+OpenGL2 Example" action:@selector(terminate:) keyEquivalent:@"q"];
    [menuItem setKeyEquivalentModifierMask:NSEventModifierFlagCommand];
	
    menuItem = [[NSMenuItem alloc] init];
    [menuItem setSubmenu:appMenu];
	
    [mainMenuBar addItem:menuItem];
	
    appMenu = nil;
    [NSApp setMainMenu:mainMenuBar];
}

-(void)dealloc
{
    _window = nil;
}

-(void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
	// Make the application a foreground application (else it won't receive keyboard events)
	ProcessSerialNumber psn = {0, kCurrentProcess};
	TransformProcessType(&psn, kProcessTransformToForegroundApplication);

	// Menu
    [self setupMenu];
	
    NSOpenGLPixelFormatAttribute attrs[] =
    {
        NSOpenGLPFADoubleBuffer,
        NSOpenGLPFADepthSize, 32,
        0
    };
	
    NSOpenGLPixelFormat* format = [[NSOpenGLPixelFormat alloc] initWithAttributes:attrs];
    ImGuiExampleView* view = [[ImGuiExampleView alloc] initWithFrame:self.window.frame pixelFormat:format];
    format = nil;
#if MAC_OS_X_VERSION_MAX_ALLOWED >= 1070
    if (floor(NSAppKitVersionNumber) > NSAppKitVersionNumber10_6)
        [view setWantsBestResolutionOpenGLSurface:YES];
#endif // MAC_OS_X_VERSION_MAX_ALLOWED >= 1070
    [self.window setContentView:view];
	
    if ([view openGLContext] == nil)
        NSLog(@"No OpenGL Context!");

    // Setup Dear ImGui binding
    IMGUI_CHECKVERSION();
    ImGui::CreateContext();
    ImGuiIO& io = ImGui::GetIO(); (void)io;
    //io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;  // Enable Keyboard Controls

    ImGui_ImplOSX_Init();
    ImGui_ImplOpenGL2_Init();

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

    // 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 'misc/fonts/README.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);
}

@end

int main(int argc, const char* argv[])
{
	@autoreleasepool
	{
		NSApp = [NSApplication sharedApplication];
		ImGuiExampleAppDelegate* delegate = [[ImGuiExampleAppDelegate alloc] init];
		[[NSApplication sharedApplication] setDelegate:delegate];
		[NSApp run];
	}
	return NSApplicationMain(argc, argv);
}