From e0003dded5a676a2f1d3f80c9df6dbb044176aec Mon Sep 17 00:00:00 2001
From: Christopher Arndt <chris@chrisarndt.de>
Date: Tue, 9 Apr 2024 22:12:53 +0200
Subject: [PATCH] Add C++ helloworld example

Signed-off-by: Christopher Arndt <chris@chrisarndt.de>
---
 .gitignore             |  5 +--
 CMakeLists.txt         | 19 ++++++++++
 lib/nanogui            |  1 +
 nanogui_helloworld.cpp | 86 ++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 108 insertions(+), 3 deletions(-)
 create mode 100644 CMakeLists.txt
 create mode 120000 lib/nanogui
 create mode 100644 nanogui_helloworld.cpp

diff --git a/.gitignore b/.gitignore
index 68751ca..705b9f0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,11 +15,8 @@ dist/
 downloads/
 eggs/
 .eggs/
-lib/
-lib64/
 parts/
 sdist/
-var/
 wheels/
 share/python-wheels/
 *.egg-info/
@@ -194,3 +191,5 @@ cython_debug/
 *.out
 *.app
 
+# nanogui lib
+lib/nanogui/
diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 0000000..6898337
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,19 @@
+cmake_minimum_required(VERSION 3.13)
+project(nanogui_helloworld)
+
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED YES)
+set(NANOGUI_BUILD_EXAMPLES OFF)
+set(NANOGUI_BUILD_PYTHON OFF)
+set(NANOGUI_BUILD_SHARED OFF)
+
+add_subdirectory(lib/nanogui)
+include_directories(lib/nanogui/include)
+include_directories(${NANOGUI_EXTRA_INCS})
+add_definitions(${NANOGUI_EXTRA_DEFS})
+
+set_property(TARGET glfw glfw_objects nanogui PROPERTY FOLDER "dependencies")
+
+add_executable(nanogui_helloworld nanogui_helloworld.cpp)
+target_link_libraries(nanogui_helloworld nanogui ${NANOGUI_EXTRA_LIBS})
+
diff --git a/lib/nanogui b/lib/nanogui
new file mode 120000
index 0000000..4183cf3
--- /dev/null
+++ b/lib/nanogui
@@ -0,0 +1 @@
+../../nanogui
\ No newline at end of file
diff --git a/nanogui_helloworld.cpp b/nanogui_helloworld.cpp
new file mode 100644
index 0000000..1b5083f
--- /dev/null
+++ b/nanogui_helloworld.cpp
@@ -0,0 +1,86 @@
+/*
+    src/nanogui_helloworld.cpp -- C++ version of an helloworld example application
+*/
+
+#include <nanogui/opengl.h>
+#include <nanogui/screen.h>
+#include <nanogui/window.h>
+#include <nanogui/layout.h>
+#include <nanogui/label.h>
+#include <nanogui/button.h>
+
+#include <iostream>
+
+using namespace nanogui;
+
+class HelloWorldApplication : public Screen {
+public:
+    HelloWorldApplication() : Screen(Vector2i(400, 300), "NanoGUI Hello World") {
+        inc_ref();
+        window = new Window(this, "Demo Window");
+        window->set_layout(new BoxLayout(Orientation::Vertical, Alignment::Middle, 20, 20));
+        resize_event(size());
+
+        new Label(window, "NanoGUI Demo", "sans-bold");
+
+        Button *b = new Button(window, "Say hello!");
+        b->set_callback([] { std::cout << "Well, 'ello there!" << std::endl; });
+        b->set_tooltip("Push me!");
+
+        perform_layout();
+    }
+
+    virtual bool resize_event(const Vector2i &size) {
+        window->set_fixed_size(size);
+        window->set_size(size);
+        window->center();
+        window->perform_layout(nvg_context());
+        return true;
+    }
+
+    virtual bool keyboard_event(int key, int scancode, int action, int modifiers) {
+        if (Screen::keyboard_event(key, scancode, action, modifiers))
+            return true;
+        if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS) {
+            set_visible(false);
+            return true;
+        }
+        return false;
+    }
+
+    virtual void draw(NVGcontext *ctx) {
+        /* Draw the user interface */
+        Screen::draw(ctx);
+    }
+
+private:
+    Window *window;
+};
+
+int main(int /* argc */, char ** /* argv */) {
+    try {
+        nanogui::init();
+
+        /* scoped variables */ {
+            ref<HelloWorldApplication> app = new HelloWorldApplication();
+            app->dec_ref();
+            app->draw_all();
+            app->set_visible(true);
+            nanogui::mainloop(1 / 60.f * 1000);
+        }
+
+        nanogui::shutdown();
+    } catch (const std::exception &e) {
+        std::string error_msg = std::string("Caught a fatal error: ") + std::string(e.what());
+        #if defined(_WIN32)
+            MessageBoxA(nullptr, error_msg.c_str(), NULL, MB_ICONERROR | MB_OK);
+        #else
+            std::cerr << error_msg << std::endl;
+        #endif
+        return -1;
+    } catch (...) {
+        std::cerr << "Caught an unknown error!" << std::endl;
+    }
+
+    return 0;
+}