standalone_sdl2.cpp

// dear imgui: standalone example application for SDL2 + OpenGL
// If you are new to dear imgui, see examples/README.txt and documentation at the top of imgui.cpp.
// (SDL is a cross-platform general purpose library for handling windows, inputs, OpenGL/Vulkan graphics context creation, etc.)

// **DO NOT USE THIS CODE IF YOUR CODE/ENGINE IS USING MODERN OPENGL (SHADERS, VBO, VAO, etc.)**
// **Prefer using the code in the example_sdl_opengl3/ folder**
// See imgui_impl_sdl.cpp for details.

#include "imgui.h"
#include "imgui/examples/imgui_impl_sdl.h"
#include "imgui/examples/imgui_impl_opengl2.h"
#include "menu.h"
#include "sdlmenu.h"
#include "menuimpl.h"
#include <stdio.h>
#include <SDL.h>
#include <SDL_opengl.h>

int main(int argc, char** args)
{
	float scaleFactor = 1;
	//Get the scaling factor
	for (int i = 0; i < argc; i++)
		if (strstr(args[i], "-scale="))
			sscanf(args[i], "-scale=%f", &scaleFactor);

	printf("ImGui scale: %f\n", scaleFactor);

	// Setup SDL
	if (SDL_Init(SDL_INIT_VIDEO|SDL_INIT_TIMER) != 0)
	{
		printf("Error: %s\n", SDL_GetError());
		return -1;
	}

	// Setup window
	SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
	SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
	SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 8);
	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2);
	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
	SDL_DisplayMode current;
	SDL_GetCurrentDisplayMode(0, &current);
	SDL_WindowFlags window_flags = (SDL_WindowFlags)(SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
	SDL_Window* window = SDL_CreateWindow("m0dular.cc standalone menu", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280 * scaleFactor, 720 * scaleFactor, window_flags);
	SDL_GLContext gl_context = SDL_GL_CreateContext(window);
	//SDL_GL_SetSwapInterval(1); // Enable vsync

	// Setup Dear ImGui context
	IMGUI_CHECKVERSION();

	SDLMenu::InitializeContext(gl_context, window);

	ImGuiIO& io = ImGui::GetIO(); (void)io;
	//io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard; // Enable Keyboard Controls

	Menu::InitializeStyle();
	Menu::InitializeFonts();

	io.FontGlobalScale = scaleFactor;
	// 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 \\ !

	ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);

	// Main loop
	bool done = false;
	while (!done)
	{
		// Poll and handle events (inputs, window resize, etc.)
		// You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your inputs.
		// - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application.
		// - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application.
		// Generally you may always pass all inputs to dear imgui, and hide them from your application based on those two flags.
		SDL_Event event;
		while (SDL_PollEvent(&event))
		{
			SDLMenu::PollEvent(&event);
			if (event.type == SDL_QUIT)
				done = true;
		}

		SDLMenu::NewFrame(window);

		MenuImpl::Render();

		// Rendering
		ImGui::Render();
		glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y);
		glClearColor(clear_color.x, clear_color.y, clear_color.z, clear_color.w);
		glClear(GL_COLOR_BUFFER_BIT);
		//glUseProgram(0); // You may want this if using this code in an OpenGL 3+ context where shaders may be bound
		ImGui_ImplOpenGL2_RenderDrawData(ImGui::GetDrawData());
		SDL_GL_SwapWindow(window);
	}

	// Cleanup
	ImGui_ImplOpenGL2_Shutdown();
	ImGui_ImplSDL2_Shutdown();
	ImGui::DestroyContext();

	SDL_GL_DeleteContext(gl_context);
	SDL_DestroyWindow(window);
	SDL_Quit();

	return 0;
}