Initial code structure

25 files changed, 647 insertions, 13 deletions

diff --git a/.gitignore b/.gitignore
index 95ff04c..223be0c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -78,4 +78,6 @@ CMakeLists.txt.user*
 *.exe
 
 .vscode/c_cpp_properties.json
+.vscode/settings.json
 build*/
+imgui.ini
diff --git a/3rdparty/imgui/CMakeLists.txt b/3rdparty/imgui/CMakeLists.txt
index 191f1ea..3382d72 100644
--- a/3rdparty/imgui/CMakeLists.txt
+++ b/3rdparty/imgui/CMakeLists.txt
@@ -1,2 +1,83 @@
-file(GLOB_RECURSE IMGUI_SOURCES ${CMAKE_CURRENT_LIST_DIR}/*.cpp)
-add_library(imgui IMGUI_SOURCES)
+set(IMGUI_SOURCES
+	imgui.h
+	imgui.cpp
+	imconfig.h
+	imgui_internal.h
+	imgui_demo.cpp
+	imgui_draw.cpp
+	imgui_tables.cpp
+	imgui_widgets.cpp
+	imstb_rectpack.h
+	imstb_textedit.h
+	imstb_truetype.h
+
+	# Since we only use GLFW to manage windows, application can't be built without GLFW
+	backend/imgui_impl_glfw.h
+	backend/imgui_impl_glfw.cpp
+)
+
+option(IMGUI_INCLUDE_OPENGL2_BACKEND ON)
+if(IMGUI_INCLUDE_OPENGL2_BACKEND)
+	message("ImGui: - building with OpenGL2 backend")
+	list(APPEND IMGUI_SOURCES
+		backend/imgui_impl_opengl2.h
+		backend/imgui_impl_opengl2.cpp
+	)
+endif()
+
+option(IMGUI_INCLUDE_OPENGL3_BACKEND ON)
+if(IMGUI_INCLUDE_OPENGL3_BACKEND)
+	message("ImGui: - building with OpenGL3 backend")
+	list(APPEND IMGUI_SOURCES
+		backend/imgui_impl_opengl3.h
+		backend/imgui_impl_opengl3.cpp
+	)
+endif()
+
+option(IMGUI_INCLUDE_VULKAN_BACKEND ON)
+if(IMGUI_INCLUDE_VULKAN_BACKEND)
+	message("ImGui: - building with Vulkan backend")
+	list(APPEND IMGUI_SOURCES
+		backend/imgui_impl_vulkan.h
+		backend/imgui_impl_vulkan.cpp
+	)
+endif()
+
+if(WIN32)
+	option(IMGUI_INCLUDE_DX11_BACKEND ON)
+	if(IMGUI_INCLUDE_DX11_BACKEND)
+		message("ImGui: - building with DirectX11 backend")
+		list(APPEND IMGUI_SOURCES
+		backend/imgui_impl_dx11.h
+		backend/imgui_impl_dx11.cpp
+		)
+	endif()
+
+	option(IMGUI_INCLUDE_DX12_BACKEND ON)
+	if(IMGUI_INCLUDE_DX12_BACKEND)
+		message("ImGui: - building with DirectX12 backend")
+		list(APPEND IMGUI_SOURCES
+		backend/imgui_impl_dx12.h
+		backend/imgui_impl_dx12.cpp
+		)
+	endif()
+elseif(APPLE)
+	option(IMGUI_INCLUDE_METAL_BACKEND ON)
+	if(IMGUI_INCLUDE_METAL_BACKEND)
+		message("ImGui: - building with Metal backend")
+		list(APPEND IMGUI_SOURCES
+			backend/imgui_impl_metal.h
+			backend/imgui_impl_metal.mm
+		)
+	endif()
+endif()
+
+add_library(imgui ${IMGUI_SOURCES})
+target_compile_definitions(imgui
+PRIVATE
+	IMGUI_IMPL_OPENGL_LOADER_GLAD=1
+)
+target_include_directories(imgui
+PRIVATE
+	${CMAKE_SOURCE_DIR}/3rdparty/imgui
+)
diff --git a/3rdparty/imnodes/CMakeLists.txt b/3rdparty/imnodes/CMakeLists.txt
index 16b007a..bb1290c 100644
--- a/3rdparty/imnodes/CMakeLists.txt
+++ b/3rdparty/imnodes/CMakeLists.txt
@@ -1,2 +1,10 @@
-file(GLOB_RECURSE IMNODES_SOURCES ${CMAKE_CURRENT_LIST_DIR}/*.cpp)
-add_library(imnodes IMNODES_SOURCES)
+set(IMNODES_SOURCES
+	imnodes.h
+	imnodes.cpp
+)
+
+add_library(imnodes ${IMNODES_SOURCES})
+target_include_directories(imnodes PRIVATE
+	${CMAKE_SOURCE_DIR}/3rdparty/imnodes
+	${CMAKE_SOURCE_DIR}/3rdparty/imgui
+)
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4b6f7ba..aeb7b0e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,7 @@
 cmake_minimum_required(VERSION 3.5)
 project(Cplt LANGUAGES CXX)
+set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 option(FORCE_COLORED_OUTPUT "Always produce ANSI-colored output (GNU/Clang only)." ON)
 if(FORCE_COLORED_OUTPUT)
@@ -10,6 +12,8 @@ if(FORCE_COLORED_OUTPUT)
 	endif()
 endif()
 
+set(LINUX ${CMAKE_SYSTEM_NAME} MATCHES "Linux")
+
 include(${CMAKE_BINARY_DIR}/conanbuildinfo.cmake)
 conan_basic_setup()
 
diff --git a/conanfile.txt b/conanfile.txt
index 2bf6348..4ddf420 100644
--- a/conanfile.txt
+++ b/conanfile.txt
@@ -1,5 +1,6 @@
 [requires]
 argparse/2.1
+sqlite3/3.35.2
 glfw/3.3.2
 glad/0.1.34
 doctest/2.4.4
diff --git a/core/CMakeLists.txt b/core/CMakeLists.txt
index f2077a3..0eb4900 100644
--- a/core/CMakeLists.txt
+++ b/core/CMakeLists.txt
@@ -1,6 +1,6 @@
-project(CpltCore LANGUAGES CXX)
-set(CMAKE_CXX_STANDARD 20)
-set(CMAKE_CXX_STANDARD_REQUIRED ON)
+option(BUILD_CORE_WITH_UNITY_BUILD OFF)
+option(BUILD_CORE_MAIN "Whether to compile the main executable or not." ON)
+option(BUILD_CORE_TESTS "Whether to compile the tests executable or not." OFF)
 
 function(add_source_group GROUP_NAME GROUP_SOURCES)
 	set(${GROUP_NAME} ${GROUP_SOURCES})
@@ -11,9 +11,26 @@ function(add_source_group GROUP_NAME GROUP_SOURCES)
 endfunction()
 
 set(ENTRYPOINT_MODULE_SOURCES
+	src/Entrypoint/main.cpp
+	src/Entrypoint/Common.hpp
+	src/Entrypoint/Common.cpp
+	src/Entrypoint/OpenGL2.hpp
+	src/Entrypoint/OpenGL2.cpp
+	src/Entrypoint/OpenGL3.hpp
+	src/Entrypoint/OpenGL3.cpp
+	src/Entrypoint/Vulkan.hpp
+	src/Entrypoint/Vulkan.cpp
+	src/Entrypoint/DirectX11.hpp
+	src/Entrypoint/DirectX11.cpp
+	src/Entrypoint/DirectX12.hpp
+	src/Entrypoint/DirectX12.cpp
+	src/Entrypoint/Metal.hpp
+	src/Entrypoint/Metal.mm
 )
 
 add_source_group(UI_MODULE_SOURCES
+	src/UI/Export.hpp
+	src/UI/Export.cpp
 )
 
 add_source_group(UTILS_MODULE_SOURCES
@@ -33,6 +50,7 @@ set(UTILS_DIALOG_MODULE_SOURCES
 	src/Utils/Dialog/Dialog.cpp
 )
 if(APPLE)
+	find_library(COCOA_LIBRARY Cocoa)
     list(APPEND UTILS_DIALOG_MODULE_SOURCES
         src/Utils/Dialog/Dialog_macos.mm
     )
@@ -41,6 +59,8 @@ elseif(WIN32)
         src/Utils/Dialog/Dialog_win32.cpp
     )
 elseif(LINUX)
+	find_package(PkgConfig REQUIRED)
+	pkg_check_modules(GTK3 REQUIRED gtk+-3.0)
     list(APPEND UTILS_DIALOG_MODULE_SOURCES
         src/Utils/Dialog/Dialog_linux.cpp
     )
@@ -60,14 +80,32 @@ function(add_executable_variant TARGET_NAME)
 		${CMAKE_SOURCE_DIR}/3rdparty/imgui
 		${CMAKE_SOURCE_DIR}/3rdparty/imnodes
 	)
-	target_link_libraries(${TARGET_NAME} PRIVATE ${CONAN_LIBS})
+	target_link_libraries(${TARGET_NAME}
+	PRIVATE
+		${CONAN_LIBS}
+		imgui
+		imnodes
+	)
 	target_compile_definitions(${TARGET_NAME}
 	PRIVATE
 		PLATFORM_WIN32=$<BOOL:${WIN32}>
 		PLATFORM_MACOS=$<BOOL:${APPLE}>
 		PLATFORM_LINUX=$<BOOL:${LINUX}>
+		IMGUI_INCLUDE_OPENGL2_BACKEND=$<BOOL:${IMGUI_INCLUDE_OPENGL2_BACKEND}>
+		IMGUI_INCLUDE_OPENGL3_BACKEND=$<BOOL:${IMGUI_INCLUDE_OPENGL3_BACKEND}>
+		IMGUI_INCLUDE_VULKAN_BACKEND=$<BOOL:${IMGUI_INCLUDE_VULKAN_BACKEND}>
+		IMGUI_INCLUDE_DX11_BACKEND=$<BOOL:${IMGUI_INCLUDE_DX11_BACKEND}>
+		IMGUI_INCLUDE_DX12_BACKEND=$<BOOL:${IMGUI_INCLUDE_DX12_BACKEND}>
+		IMGUI_INCLUDE_METAL_BACKEND=$<BOOL:${IMGUI_INCLUDE_METAL_BACKEND}>
 	)
 
+	if(APPLE)
+		target_link_libraries(${TARGET_NAME} PUBLIC ${COCOA_LIBRARY})
+	elseif(LINUX)
+		target_link_libraries(${TARGET_NAME} PUBLIC ${GTK3_LIBRARIES})
+		target_include_directories(${TARGET_NAME} PRIVATE ${GTK3_INCLUDE_DIRS})
+	endif()
+
 	# No console window when targetting windows
 	if(WIN32)
 		if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU" OR CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
@@ -81,11 +119,11 @@ function(add_executable_variant TARGET_NAME)
 		endif()
 	endif()
 
-	if(${CMAKE_UNITY_BUILD})
+	if(BUILD_CORE_WITH_UNITY_BUILD)
 		message("CpltCore: - using unity build")
 		set_target_properties(${TARGET_NAME}
 		PROPERTIES
-			# UNITY_BUILD property is automatically set when CMAKE_UNITY_BUILD is set
+			UNITY_BUILD ON
 			UNITY_BUILD_MODE GROUP
 		)
 	else()
@@ -93,7 +131,11 @@ function(add_executable_variant TARGET_NAME)
 	endif()
 endfunction()
 
-add_executable_variant(CpltCore_main)
-target_compile_definitions(CpltCore_main PRIVATE DOCTEST_CONFIG_DISABLE=1)
+if(BUILD_CORE_MAIN)
+	add_executable_variant(CpltCore_main)
+	target_compile_definitions(CpltCore_main PRIVATE DOCTEST_CONFIG_DISABLE=1)
+endif()
 
-add_executable_variant(CpltCore_test)
+if(BUILD_CORE_TESTS)
+	add_executable_variant(CpltCore_test)
+endif()
diff --git a/core/fonts/NotoSansSC-LICENSE.txt b/core/fonts/NotoSansSC-LICENSE.txt
new file mode 100644
index 0000000..075d1ae
--- /dev/null
+++ b/core/fonts/NotoSansSC-LICENSE.txt
@@ -0,0 +1,91 @@
+This Font Software is licensed under the SIL Open Font License, Version 1.1.

+This license is copied below, and is also available with a FAQ at:

+http://scripts.sil.org/OFL

+

+

+-----------------------------------------------------------

+SIL OPEN FONT LICENSE Version 1.1 - 26 February 2007

+-----------------------------------------------------------

+

+PREAMBLE

+The goals of the Open Font License (OFL) are to stimulate worldwide

+development of collaborative font projects, to support the font creation

+efforts of academic and linguistic communities, and to provide a free and

+open framework in which fonts may be shared and improved in partnership

+with others.

+

+The OFL allows the licensed fonts to be used, studied, modified and

+redistributed freely as long as they are not sold by themselves. The

+fonts, including any derivative works, can be bundled, embedded, 

+redistributed and/or sold with any software provided that any reserved

+names are not used by derivative works. The fonts and derivatives,

+however, cannot be released under any other type of license. The

+requirement for fonts to remain under this license does not apply

+to any document created using the fonts or their derivatives.

+

+DEFINITIONS

+"Font Software" refers to the set of files released by the Copyright

+Holder(s) under this license and clearly marked as such. This may

+include source files, build scripts and documentation.

+

+"Reserved Font Name" refers to any names specified as such after the

+copyright statement(s).

+

+"Original Version" refers to the collection of Font Software components as

+distributed by the Copyright Holder(s).

+

+"Modified Version" refers to any derivative made by adding to, deleting,

+or substituting -- in part or in whole -- any of the components of the

+Original Version, by changing formats or by porting the Font Software to a

+new environment.

+

+"Author" refers to any designer, engineer, programmer, technical

+writer or other person who contributed to the Font Software.

+

+PERMISSION & CONDITIONS

+Permission is hereby granted, free of charge, to any person obtaining

+a copy of the Font Software, to use, study, copy, merge, embed, modify,

+redistribute, and sell modified and unmodified copies of the Font

+Software, subject to the following conditions:

+

+1) Neither the Font Software nor any of its individual components,

+in Original or Modified Versions, may be sold by itself.

+

+2) Original or Modified Versions of the Font Software may be bundled,

+redistributed and/or sold with any software, provided that each copy

+contains the above copyright notice and this license. These can be

+included either as stand-alone text files, human-readable headers or

+in the appropriate machine-readable metadata fields within text or

+binary files as long as those fields can be easily viewed by the user.

+

+3) No Modified Version of the Font Software may use the Reserved Font

+Name(s) unless explicit written permission is granted by the corresponding

+Copyright Holder. This restriction only applies to the primary font name as

+presented to the users.

+

+4) The name(s) of the Copyright Holder(s) or the Author(s) of the Font

+Software shall not be used to promote, endorse or advertise any

+Modified Version, except to acknowledge the contribution(s) of the

+Copyright Holder(s) and the Author(s) or with their explicit written

+permission.

+

+5) The Font Software, modified or unmodified, in part or in whole,

+must be distributed entirely under this license, and must not be

+distributed under any other license. The requirement for fonts to

+remain under this license does not apply to any document created

+using the Font Software.

+

+TERMINATION

+This license becomes null and void if any of the above conditions are

+not met.

+

+DISCLAIMER

+THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF

+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT

+OF COPYRIGHT, PATENT, TRADEMARK, OR OTHER RIGHT. IN NO EVENT SHALL THE

+COPYRIGHT HOLDER BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,

+INCLUDING ANY GENERAL, SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL

+DAMAGES, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

+FROM, OUT OF THE USE OR INABILITY TO USE THE FONT SOFTWARE OR FROM

+OTHER DEALINGS IN THE FONT SOFTWARE.

diff --git a/core/fonts/NotoSansSC-Regular.otf b/core/fonts/NotoSansSC-Regular.otf
new file mode 100644
index 0000000..fdb0506
--- /dev/null
+++ b/core/fonts/NotoSansSC-Regular.otf
diff --git a/core/src/Entrypoint/Common.cpp b/core/src/Entrypoint/Common.cpp
new file mode 100644
index 0000000..62baf9d
--- /dev/null
+++ b/core/src/Entrypoint/Common.cpp
@@ -0,0 +1,11 @@
+#include "Common.hpp"
+
+#include <iostream>
+
+GLFWwindow* RenderingBackend::GetWindow() const {
+    return mWindow;
+}
+
+void RenderingBackend::GlfwErrorCallback(int error, const char* message) {
+    std::cerr << "GLFW Error " << error << ": " << message << "\n";
+}
diff --git a/core/src/Entrypoint/Common.hpp b/core/src/Entrypoint/Common.hpp
new file mode 100644
index 0000000..2a4dcbf
--- /dev/null
+++ b/core/src/Entrypoint/Common.hpp
@@ -0,0 +1,20 @@
+#pragma once
+
+#include <glad/glad.h>
+ 
+#include <GLFW/glfw3.h>
+
+class RenderingBackend {
+protected:
+	GLFWwindow* mWindow;
+
+public:
+	virtual ~RenderingBackend() = default;
+	virtual void BeginFrame() = 0;
+	virtual void EndFrame() = 0;
+
+    GLFWwindow* GetWindow() const;
+
+    /// Common GLFW error handle callback for each rendering backend to use.
+	static void GlfwErrorCallback(int error, const char* message);
+};
diff --git a/core/src/Entrypoint/DirectX11.cpp b/core/src/Entrypoint/DirectX11.cpp
new file mode 100644
index 0000000..617447c
--- /dev/null
+++ b/core/src/Entrypoint/DirectX11.cpp
@@ -0,0 +1,13 @@
+#include "DirectX11.hpp"
+
+DirectX11Backend::DirectX11Backend() {
+	// TODO
+}
+
+void DirectX11Backend::BeginFrame() {
+	// TODO
+}
+
+void DirectX11Backend::EndFrame() {
+	// TODO
+}
diff --git a/core/src/Entrypoint/DirectX11.hpp b/core/src/Entrypoint/DirectX11.hpp
new file mode 100644
index 0000000..134a20f
--- /dev/null
+++ b/core/src/Entrypoint/DirectX11.hpp
@@ -0,0 +1,11 @@
+#pragma once
+
+#include "Entrypoint/Common.hpp"
+
+class DirectX11Backend : public RenderingBackend {
+public:
+	DirectX11Backend();
+	virtual ~DirectX11Backend() = default;
+	virtual void BeginFrame() override;
+	virtual void EndFrame() override;
+};
diff --git a/core/src/Entrypoint/DirectX12.cpp b/core/src/Entrypoint/DirectX12.cpp
new file mode 100644
index 0000000..1769d24
--- /dev/null
+++ b/core/src/Entrypoint/DirectX12.cpp
@@ -0,0 +1,13 @@
+#include "DirectX12.hpp"
+
+DirectX12Backend::DirectX12Backend() {
+	// TODO
+}
+
+void DirectX12Backend::BeginFrame() {
+	// TODO
+}
+
+void DirectX12Backend::EndFrame() {
+	// TODO
+}
diff --git a/core/src/Entrypoint/DirectX12.hpp b/core/src/Entrypoint/DirectX12.hpp
new file mode 100644
index 0000000..8b9a4f0
--- /dev/null
+++ b/core/src/Entrypoint/DirectX12.hpp
@@ -0,0 +1,11 @@
+#pragma once
+
+#include "Entrypoint/Common.hpp"
+
+class DirectX12Backend : public RenderingBackend {
+public:
+	DirectX12Backend();
+	virtual ~DirectX12Backend() = default;
+	virtual void BeginFrame() override;
+	virtual void EndFrame() override;
+};
diff --git a/core/src/Entrypoint/Metal.hpp b/core/src/Entrypoint/Metal.hpp
new file mode 100644
index 0000000..cd96d0f
--- /dev/null
+++ b/core/src/Entrypoint/Metal.hpp
@@ -0,0 +1,11 @@
+#pragma once
+
+#include "Entrypoint/Common.hpp"
+
+class MetalBackend : public RenderingBackend {
+public:
+	MetalBackend();
+	virtual ~MetalBackend() = default;
+	virtual void BeginFrame() override;
+	virtual void EndFrame() override;
+};
diff --git a/core/src/Entrypoint/Metal.mm b/core/src/Entrypoint/Metal.mm
new file mode 100644
index 0000000..3f69634
--- /dev/null
+++ b/core/src/Entrypoint/Metal.mm
@@ -0,0 +1,13 @@
+#include "Metal.hpp"
+
+MetalBackend::MetalBackend() {
+	// TODO
+}
+
+void MetalBackend::BeginFrame() {
+	// TODO
+}
+
+void MetalBackend::EndFrame() {
+	// TODO
+}
diff --git a/core/src/Entrypoint/OpenGL2.cpp b/core/src/Entrypoint/OpenGL2.cpp
new file mode 100644
index 0000000..de13a02
--- /dev/null
+++ b/core/src/Entrypoint/OpenGL2.cpp
@@ -0,0 +1,70 @@
+#include "OpenGL2.hpp"
+
+#include <glad/glad.h>
+
+#include <GLFW/glfw3.h>
+#include <backend/imgui_impl_glfw.h>
+#include <backend/imgui_impl_opengl2.h>
+#include <imgui.h>
+#include <stdexcept>
+
+OpenGL2Backend::OpenGL2Backend() {
+#if IMGUI_INCLUDE_OPENGL2_BACKEND
+	glfwSetErrorCallback(GlfwErrorCallback);
+	if (!glfwInit()) {
+		throw std::runtime_error("Failed to initialize GLFW.");
+	}
+
+	mWindow = glfwCreateWindow(1280, 720, "Cplt", nullptr, nullptr);
+	if (mWindow == nullptr) {
+		throw std::runtime_error("Failed to create GLFW window.");
+	}
+	glfwMakeContextCurrent(mWindow);
+	glfwSwapInterval(1); // Enable vsync
+
+	if (gladLoadGLLoader((GLADloadproc)glfwGetProcAddress) == 0) {
+		throw std::runtime_error("Failed to initialize OpenGL.");
+	}
+
+	IMGUI_CHECKVERSION();
+	ImGui::CreateContext();
+
+	ImGui_ImplGlfw_InitForOpenGL(mWindow, true);
+	ImGui_ImplOpenGL2_Init();
+#else
+	throw std::runtime_error("Backend opengl2 is not available in this build.\n");
+#endif
+}
+
+OpenGL2Backend::~OpenGL2Backend() {
+	ImGui_ImplOpenGL2_Shutdown();
+	ImGui_ImplGlfw_Shutdown();
+	ImGui::DestroyContext();
+
+	glfwDestroyWindow(mWindow);
+	glfwTerminate();
+}
+
+void OpenGL2Backend::BeginFrame() {
+	glfwPollEvents();
+
+	ImGui_ImplOpenGL2_NewFrame();
+	ImGui_ImplGlfw_NewFrame();
+	ImGui::NewFrame();
+}
+
+void OpenGL2Backend::EndFrame() {
+	int displayWidth, displayHeight;
+	glfwGetFramebufferSize(mWindow, &displayWidth, &displayHeight);
+	glViewport(0, 0, displayWidth, displayHeight);
+
+	const ImVec4 kClearColor = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
+	glClearColor(kClearColor.x * kClearColor.w, kClearColor.y * kClearColor.w, kClearColor.z * kClearColor.w, kClearColor.w);
+	glClear(GL_COLOR_BUFFER_BIT);
+
+	ImGui::Render();
+	ImGui_ImplOpenGL2_RenderDrawData(ImGui::GetDrawData());
+
+	glfwMakeContextCurrent(mWindow);
+	glfwSwapBuffers(mWindow);
+}
diff --git a/core/src/Entrypoint/OpenGL2.hpp b/core/src/Entrypoint/OpenGL2.hpp
new file mode 100644
index 0000000..86fbad7
--- /dev/null
+++ b/core/src/Entrypoint/OpenGL2.hpp
@@ -0,0 +1,15 @@
+#pragma once
+
+#include "Entrypoint/Common.hpp"
+
+#include <glad/glad.h>
+
+#include <GLFW/glfw3.h>
+
+class OpenGL2Backend : public RenderingBackend {
+public:
+	OpenGL2Backend();
+	virtual ~OpenGL2Backend();
+	virtual void BeginFrame() override;
+	virtual void EndFrame() override;
+};
diff --git a/core/src/Entrypoint/OpenGL3.cpp b/core/src/Entrypoint/OpenGL3.cpp
new file mode 100644
index 0000000..c1f66d5
--- /dev/null
+++ b/core/src/Entrypoint/OpenGL3.cpp
@@ -0,0 +1,85 @@
+#include "OpenGL3.hpp"
+
+#include <glad/glad.h>
+
+#include <GLFW/glfw3.h>
+#include <backend/imgui_impl_glfw.h>
+#include <backend/imgui_impl_opengl3.h>
+#include <imgui.h>
+#include <stdexcept>
+
+OpenGL3Backend::OpenGL3Backend() {
+#if IMGUI_INCLUDE_OPENGL3_BACKEND
+	glfwSetErrorCallback(GlfwErrorCallback);
+	if (!glfwInit()) {
+		throw std::runtime_error("Failed to initialize GLFW.");
+	}
+
+#	if PLATFORM_APPLE
+	// GL 3.2 + GLSL 150
+	const char* glslVersion = "#version 150";
+	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
+	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
+	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); // 3.2+ only
+	glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // Required on Mac
+#	else
+	// GL 3.0 + GLSL 130
+	const char* glslVersion = "#version 130";
+	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
+	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
+	//glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);  // 3.2+ only
+	//glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);            // 3.0+ only
+#	endif
+
+	mWindow = glfwCreateWindow(1280, 720, "Cplt", nullptr, nullptr);
+	if (mWindow == nullptr) {
+		throw std::runtime_error("Failed to create GLFW window.");
+	}
+	glfwMakeContextCurrent(mWindow);
+	glfwSwapInterval(1); // Enable vsync
+
+	if (gladLoadGLLoader((GLADloadproc)glfwGetProcAddress) == 0) {
+		throw std::runtime_error("Failed to initialize OpenGL.");
+	}
+
+	IMGUI_CHECKVERSION();
+	ImGui::CreateContext();
+
+	ImGui_ImplGlfw_InitForOpenGL(mWindow, true);
+	ImGui_ImplOpenGL3_Init(glslVersion);
+#else
+	throw std::runtime_error("Backend opengl3 is not available in this build.\n");
+#endif
+}
+
+OpenGL3Backend::~OpenGL3Backend() {
+	ImGui_ImplOpenGL3_Shutdown();
+	ImGui_ImplGlfw_Shutdown();
+	ImGui::DestroyContext();
+
+	glfwDestroyWindow(mWindow);
+	glfwTerminate();
+}
+
+void OpenGL3Backend::BeginFrame() {
+	glfwPollEvents();
+
+	ImGui_ImplOpenGL3_NewFrame();
+	ImGui_ImplGlfw_NewFrame();
+	ImGui::NewFrame();
+}
+
+void OpenGL3Backend::EndFrame() {
+	int displayWidth, displayHeight;
+	glfwGetFramebufferSize(mWindow, &displayWidth, &displayHeight);
+	glViewport(0, 0, displayWidth, displayHeight);
+
+	const ImVec4 kClearColor = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
+	glClearColor(kClearColor.x * kClearColor.w, kClearColor.y * kClearColor.w, kClearColor.z * kClearColor.w, kClearColor.w);
+	glClear(GL_COLOR_BUFFER_BIT);
+
+	ImGui::Render();
+	ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
+
+	glfwSwapBuffers(mWindow);
+}
diff --git a/core/src/Entrypoint/OpenGL3.hpp b/core/src/Entrypoint/OpenGL3.hpp
new file mode 100644
index 0000000..29086a2
--- /dev/null
+++ b/core/src/Entrypoint/OpenGL3.hpp
@@ -0,0 +1,15 @@
+#pragma once
+
+#include "Entrypoint/Common.hpp"
+
+#include <glad/glad.h>
+
+#include <GLFW/glfw3.h>
+
+class OpenGL3Backend : public RenderingBackend {
+public:
+	OpenGL3Backend();
+	virtual ~OpenGL3Backend() ;
+	virtual void BeginFrame() override;
+	virtual void EndFrame() override;
+};
diff --git a/core/src/Entrypoint/Vulkan.cpp b/core/src/Entrypoint/Vulkan.cpp
new file mode 100644
index 0000000..5af1772
--- /dev/null
+++ b/core/src/Entrypoint/Vulkan.cpp
@@ -0,0 +1,13 @@
+#include "Vulkan.hpp"
+
+VulkanBackend::VulkanBackend() {
+	// TODO
+}
+
+void VulkanBackend::BeginFrame() {
+	// TODO
+}
+
+void VulkanBackend::EndFrame() {
+	// TODO
+}
diff --git a/core/src/Entrypoint/Vulkan.hpp b/core/src/Entrypoint/Vulkan.hpp
new file mode 100644
index 0000000..6404806
--- /dev/null
+++ b/core/src/Entrypoint/Vulkan.hpp
@@ -0,0 +1,11 @@
+#pragma once
+
+#include "Entrypoint/Common.hpp"
+
+class VulkanBackend : public RenderingBackend {
+public:
+	VulkanBackend();
+	virtual ~VulkanBackend() = default;
+	virtual void BeginFrame() override;
+	virtual void EndFrame() override;
+};
diff --git a/core/src/Entrypoint/main.cpp b/core/src/Entrypoint/main.cpp
new file mode 100644
index 0000000..3adf757
--- /dev/null
+++ b/core/src/Entrypoint/main.cpp
@@ -0,0 +1,91 @@
+#include "Entrypoint/Common.hpp"
+#include "Entrypoint/DirectX11.hpp"
+#include "Entrypoint/DirectX12.hpp"
+#include "Entrypoint/Metal.hpp"
+#include "Entrypoint/OpenGL2.hpp"
+#include "Entrypoint/OpenGL3.hpp"
+#include "Entrypoint/Vulkan.hpp"
+
+#include <glad/glad.h>
+
+#include <GLFW/glfw3.h>
+#include <imgui.h>
+#include <argparse/argparse.hpp>
+#include <iostream>
+#include <memory>
+#include <string>
+
+using namespace std::literals::string_literals;
+
+int main(int argc, char* argv[]) {
+	argparse::ArgumentParser parser;
+	parser.add_argument("--rendering-backend")
+		.help("Which rendering backend to use. If equals 'default', the preferred API for each platform will be used")
+		.default_value("default"s);
+
+	try {
+		parser.parse_args(argc, argv);
+	} catch (const std::runtime_error& error) {
+		std::cout << error.what() << '\n';
+		std::cout << parser;
+		return -1;
+	}
+
+	std::unique_ptr<RenderingBackend> backend;
+	auto backendOption = parser.get<std::string>("--rendering-backend");
+	if (backendOption == "default") {
+		// TODO better api selection mechanism, use lower tier if higher tier is unavilable instead of bailing
+#if PLATFORM_WIN32
+#	if IMGUI_INCLUDE_DX12_BACKEND
+		backend = std::make_unique<DirectX12Backend>();
+#	elif IMGUI_INCLUDE_DX11_BACKEND
+		backend = std::make_unique<DirectX11Backend>();
+#	elif IMGUI_INCLUDE_VULKAN_BACKEND
+		backend = std::make_unique<VulkanBackend>();
+#	elif IMGUI_INCLUDE_OPENGL3_BACKEND
+		backend = std::make_unique<OpenGL3Backend>();
+#	elif IMGUI_INCLUDE_OPENGL2_BACKEND
+		backend = std::make_unique<OpenGL2Backend>();
+#	endif
+#elif PLATFORM_MACOS
+		backend = std::make_unique<MetalBackend>();
+#elif PLATFORM_LINUX
+#	if IMGUI_INCLUDE_VULKAN_BACKEND
+		backend = std::make_unique<VulkanBackend>();
+// #	elif IMGUI_INCLUDE_OPENGL3_BACKEND
+// 		backend = std::make_unique<OpenGL3Backend>();
+#	elif IMGUI_INCLUDE_OPENGL2_BACKEND
+		backend = std::make_unique<OpenGL2Backend>();
+#	endif
+#endif
+	} else if (backendOption == "opengl2") {
+		backend = std::make_unique<OpenGL2Backend>();
+	} else if (backendOption == "opengl3") {
+		backend = std::make_unique<OpenGL3Backend>();
+	} else if (backendOption == "vulkan") {
+		backend = std::make_unique<VulkanBackend>();
+	} else if (backendOption == "dx11") {
+		backend = std::make_unique<DirectX11Backend>();
+	} else if (backendOption == "dx12") {
+		backend = std::make_unique<DirectX12Backend>();
+	} else if (backendOption == "metal") {
+		backend = std::make_unique<MetalBackend>();
+	} else {
+		std::cout << "Unknown backend '" << backendOption << "'.\n";
+		return -1;
+	}
+
+	auto& io = ImGui::GetIO();
+	io.Fonts->AddFontFromFileTTF("fonts/NotoSansSC-Regular.otf", 18, nullptr, io.Fonts->GetGlyphRangesChineseSimplifiedCommon());
+
+	auto window = backend->GetWindow();
+	bool showDemo = true;
+	while (!glfwWindowShouldClose(window)) {
+		backend->BeginFrame();
+		if (showDemo)
+			ImGui::ShowDemoWindow(&showDemo);
+		backend->EndFrame();
+	}
+
+	return 0;
+}
diff --git a/core/src/UI/Export.cpp b/core/src/UI/Export.cpp
new file mode 100644
index 0000000..d6b26dc
--- /dev/null
+++ b/core/src/UI/Export.cpp
@@ -0,0 +1 @@
+#include "Export.hpp"
diff --git a/core/src/UI/Export.hpp b/core/src/UI/Export.hpp
new file mode 100644
index 0000000..6f70f09
--- /dev/null
+++ b/core/src/UI/Export.hpp
@@ -0,0 +1 @@
+#pragma once