Magpie/Runtime/OverlayDrawer.cpp

#include "pch.h"
#include "OverlayDrawer.h"
#include "App.h"
#include "DeviceResources.h"
#include <imgui.h>
#include <imgui_internal.h>
#include "imgui_impl_magpie.h"
#include "imgui_impl_dx11.h"
#include "Renderer.h"
#include "GPUTimer.h"
#include "CursorManager.h"


OverlayDrawer::~OverlayDrawer() {
	if (_handlerID != 0) {
		App::Get().UnregisterWndProcHandler(_handlerID);
	}

	ImGui_ImplDX11_Shutdown();
	ImGui_ImplMagpie_Shutdown();
	ImGui::DestroyContext();
}

float GetDpiScale() {
	return GetDpiForWindow(App::Get().GetHwndHost()) / 96.0f;
}

static std::optional<LRESULT> WndProcHandler(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam) {
	ImGui_ImplMagpie_WndProcHandler(hWnd, msg, wParam, lParam);
	return std::nullopt;
}

bool OverlayDrawer::Initialize(ID3D11Texture2D* renderTarget) {
	auto& dr = App::Get().GetDeviceResources();

	IMGUI_CHECKVERSION();
	ImGui::CreateContext();

	ImGuiIO& io = ImGui::GetIO();
	io.ConfigFlags |= ImGuiConfigFlags_NavNoCaptureKeyboard | ImGuiConfigFlags_NoMouseCursorChange;
	
	float dpiScale = GetDpiScale();

	ImGui::StyleColorsDark();
	ImGui::GetStyle().WindowRounding = 6;
	ImGui::GetStyle().FrameBorderSize = 1;
	ImGui::GetStyle().ScaleAllSizes(dpiScale);

	io.Fonts->AddFontFromFileTTF(".\\assets\\NotoSansSC-Regular.otf", std::floor(20.0f * dpiScale), NULL);

	ImGui_ImplMagpie_Init();
	ImGui_ImplDX11_Init(dr.GetD3DDevice(), dr.GetD3DDC());

	dr.GetRenderTargetView(renderTarget, &_rtv);

	_handlerID = App::Get().RegisterWndProcHandler(WndProcHandler);

	return true;
}

void DrawUI() {
	const ImGuiViewport* main_viewport = ImGui::GetMainViewport();
	ImGui::SetNextWindowPos(ImVec2(20, 20), ImGuiCond_FirstUseEver);
	ImGui::SetNextWindowSize(ImVec2(200, 100), ImGuiCond_FirstUseEver);

	if (!ImGui::Begin("Debug", nullptr, ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoNav)) {
		// Early out if the window is collapsed, as an optimization.
		ImGui::End();
		return;
	}
	
	ImGui::Text(fmt::format("FPS: {}", App::Get().GetRenderer().GetGPUTimer().GetFramesPerSecond()).c_str());

	ImGui::End();
}

void OverlayDrawer::Draw() {
	if (!_isVisiable) {
		return;
	}

	ImGuiIO& io = ImGui::GetIO();
	CursorManager& cm = App::Get().GetCursorManager();

	bool originWantCaptureMouse = io.WantCaptureMouse;

	ImGui_ImplMagpie_NewFrame();
	ImGui_ImplDX11_NewFrame();
	ImGui::NewFrame();

	if (io.WantCaptureMouse) {
		if (!originWantCaptureMouse) {
			cm.OnCursorHoverOverlay();
		}
	} else {
		if (originWantCaptureMouse) {
			cm.OnCursorLeaveOverlay();
		}
	}

	if (ImGui::GetFrameCount() == 2) {
		// 防止从配置文件读入的窗口位置位于屏幕外
		// 选择第二帧的原因：
		// 1. 第一帧无法获取到窗口
		// 2. 因为第一帧 UI 不可见（ImGUI 的特性），所以用户不会看到窗口位置改变
		SIZE outputSize = Utils::GetSizeOfRect(App::Get().GetRenderer().GetOutputRect());
		for (ImGuiWindow* window : ImGui::GetCurrentContext()->Windows) {
			if (outputSize.cx > window->Size.x) {
				window->Pos.x = std::clamp(window->Pos.x, 0.0f, outputSize.cx - window->Size.x);
			} else {
				window->Pos.x = 0;
			}
			
			if (outputSize.cy > window->Size.y) {
				window->Pos.y = std::clamp(window->Pos.y, 0.0f, outputSize.cy - window->Size.y);
			} else {
				window->Pos.y = 0;
			}
		}
	} else if(cm.IsCursorCapturedOnOverlay()) {
		// 防止将 UI 窗口拖到屏幕外
		ImGuiWindow* window = ImGui::GetCurrentContext()->HoveredWindow;
		if (window) {
			SIZE outputSize = Utils::GetSizeOfRect(App::Get().GetRenderer().GetOutputRect());

			if (outputSize.cx > window->Size.x) {
				window->Pos.x = std::clamp(window->Pos.x, 0.0f, outputSize.cx - window->Size.x);
			} else {
				window->Pos.x = 0;
			}

			if (outputSize.cy > window->Size.y) {
				window->Pos.y = std::clamp(window->Pos.y, 0.0f, outputSize.cy - window->Size.y);
			} else {
				window->Pos.y = 0;
			}
		}
	}
	
	DrawUI();

	ImGui::Render();

	const RECT& outputRect = App::Get().GetRenderer().GetOutputRect();
	ImGui::GetDrawData()->DisplayPos = ImVec2(float(-outputRect.left), float(-outputRect.top));
	
	auto d3dDC = App::Get().GetDeviceResources().GetD3DDC();
	d3dDC->OMSetRenderTargets(1, &_rtv, NULL);
	
	ImGui_ImplDX11_RenderDrawData(ImGui::GetDrawData());
}

void OverlayDrawer::SetVisibility(bool value) {
	if (_isVisiable == value) {
		return;
	}
	_isVisiable = value;

	if (!value) {
		ImGui_ImplMagpie_ClearStates();
	}
}