跟着cherno手搓游戏引擎【7】Input轮询

在引擎程序中任何时间，任何位置都能知道按键是否按下、鼠标的位置等等信息。

与事件系统的区别：事件系统是在按下时调用并传递按键状态；轮询是每时每刻都能获取按键状态

创建基类：

YOTO/Input.h：名如其意

#pragma once
#include"YOTO/Core.h"
namespace YOTO {
	class YOTO_API Input {
	public:
		inline static bool IsKeyPressed(int keycode){
			return s_Instance->IsKeyPressedImpl(keycode);
		}
		inline static bool IsMouseButtonPressed(int button) {
			return s_Instance->IsMouseButtonPressedImpl(button);
		}
		inline static float GetMouseX() {
			return s_Instance->GetMouseXImpl();
		}
		inline static float GetMouseY() {
			return s_Instance->GetMouseYImpl();
		}
		inline static std::pair<float,float> GetMousePostion() {
			return s_Instance->GetMousePositionImpl();
		}
	protected:
		virtual bool IsKeyPressedImpl(int keycode )=0;
		virtual bool IsMouseButtonPressedImpl(int button) = 0;
		virtual float GetMouseXImpl() = 0;
		virtual float GetMouseYImpl() = 0;
		virtual  std::pair<float, float>  GetMousePositionImpl() = 0;

	private:
		static  Input* s_Instance;
	};
}

实现基类：

在Platform/Windows/下创建WindowsInput.h：

#pragma once
#include"YOTO/Input.h"
namespace YOTO {
	class WindowsInput :public Input {
	protected:
		virtual bool IsKeyPressedImpl(int keycode) override;
		virtual bool IsMouseButtonPressedImpl(int button)override;
		virtual  std::pair<float, float>  GetMousePositionImpl()override;
		virtual float GetMouseXImpl()override;
		virtual float GetMouseYImpl() override;
	};
}

WindowsInput.cpp：获取window然后用glfw自带的事件检测来

#include"ytpch.h"
#include"WindowsInput.h"
#include<GLFW/glfw3.h>
#include"YOTO/Application.h"
namespace YOTO {

	Input* Input::s_Instance = new WindowsInput();
	bool WindowsInput::IsKeyPressedImpl(int keycode)
	{// 获取GLFW原生窗口void*，转为GLFWwindow*
		auto window =static_cast<GLFWwindow*>( Application::Get().GetWindow().GetNativeWindow());
		// 用已有的GLFW函数来获取按键状态
		auto state=	glfwGetKey(window, keycode);
		return state==GLFW_PRESS|| state== GLFW_REPEAT;
	}
	bool WindowsInput::IsMouseButtonPressedImpl(int button)
	{
		auto window = static_cast<GLFWwindow*>(Application::Get().GetWindow().GetNativeWindow());
		auto state = glfwGetMouseButton(window, button);
		return state == GLFW_PRESS ;
	}
	std::pair<float, float> WindowsInput::GetMousePositionImpl()
	{
		auto window = static_cast<GLFWwindow*>(Application::Get().GetWindow().GetNativeWindow());
		double xpos, ypos;
		glfwGetCursorPos(window, &xpos, &ypos);
		return {(float)xpos,(float)ypos};
	}
	float WindowsInput::GetMouseXImpl()
	{
		auto [x, y] = GetMousePositionImpl();

		return x;
	}
	float WindowsInput::GetMouseYImpl()
	{
		auto [x, y] = GetMousePositionImpl();

		return y;
	}
}

为了能在任何时候获取到GLFWwindow，在Window.h中创建方法获取Window

#pragma once

#include"ytpch.h"
#include"YOTO/Core.h"
#include"YOTO/Event/Event.h"
namespace YOTO {
	struct WindowProps {
		std::string Title;
		unsigned int Width;
		unsigned int Height;
		WindowProps(const std::string &title="YOTO Engine",unsigned int width =1280, unsigned int height = 1280 )
			:Title(title),Width(width),Height(height){}
	};
	class YOTO_API Window {
	public:
		//用EventCallbackFn代替std::function<void(Event&)>：输入为Event&返回值为void 的函数
		using EventCallbackFn = std::function<void(Event&)>;
		virtual ~Window(){}
		//=0为纯虚函数
		virtual void OnUpdate() = 0;
		virtual unsigned int GetWidth() const = 0;
		virtual unsigned int GetHeight() const = 0;
		
		virtual void SetEventCallback(const EventCallbackFn& callback) = 0;
		virtual void SetVSync(bool enable)= 0;
		virtual bool IsVSync() const = 0;
		//返回当前窗口
		virtual void* GetNativeWindow() const=0;

		static Window* Creat(const WindowProps& props = WindowProps());

	};
}

WindowsWindow.h ：实现返回window的方法：

#pragma once
#include "YOTO/Window.h"
#include<GLFW/glfw3.h>
#include"YOTO/Log.h"
struct GLFWwindow;
namespace YOTO {
	class WindowsWindow :public Window
	{
	public :
		WindowsWindow(const WindowProps& props);
		virtual ~WindowsWindow();
		void OnUpdate() override;
		
		inline unsigned int GetWidth() const override { return m_Data.Width; };
		inline unsigned int GetHeight() const override { return m_Data.Height; };

		inline void SetEventCallback(const EventCallbackFn& callback)override
		{ m_Data.EventCallback = callback; };
		void SetVSync(bool enable) ;
		bool IsVSync()const;
		//返回window
		inline virtual void* GetNativeWindow() const { return m_Window; }
	private: 
		virtual void Init(const WindowProps& props);
		virtual void ShutDown();
	private:
		GLFWwindow* m_Window;
		struct WindowData {
			std::string Title;
			unsigned int Width, Height;
			bool VSync;
			EventCallbackFn EventCallback;
		};
		WindowData m_Data;
	};
}

Application.cpp：在Run中获取鼠标位置：

#include"ytpch.h"
#include "Application.h"

#include"Log.h"
#include<glad/glad.h>
#include"Input.h"
namespace YOTO {
#define BIND_EVENT_FN(x) std::bind(&x, this, std::placeholders::_1)

	 Application* Application::s_Instance = nullptr;

	Application::Application() {

		YT_CORE_ASSERT(!s_Instance, "Application需要为空！")
		s_Instance = this;
		//智能指针
		m_Window = std::unique_ptr<Window>(Window::Creat());
		//设置回调函数
		m_Window->SetEventCallback(BIND_EVENT_FN(Application::OnEvent));
		unsigned int id;
		glGenBuffers(1, &id);
	}
	Application::~Application() {

	}
	/// <summary>
	/// 所有的Window事件都会在这触发，作为参数e
	/// </summary>
	/// <param name="e"></param>
	void Application::OnEvent(Event& e) {
		//根据事件类型绑定对应事件
		EventDispatcher dispatcher(e);
		dispatcher.Dispatch<WindowCloseEvent>(BIND_EVENT_FN(Application::OnWindowClosed));
		//输出事件信息
		YT_CORE_INFO("{0}",e);
		for (auto it = m_LayerStack.end(); it != m_LayerStack.begin();) {
			(*--it)->OnEvent(e);
			if (e.m_Handled)
				break;
		}
	}

	bool Application::OnWindowClosed(WindowCloseEvent& e) {
		m_Running = false;
		return true;
	}
	void Application::Run() {
		WindowResizeEvent e(1280, 720);
		if (e.IsInCategory(EventCategoryApplication)) {
			YT_CORE_TRACE(e);
		}
		if (e.IsInCategory(EventCategoryInput)) {
			YT_CORE_ERROR(e);
		}

		while (m_Running)
		{
			glClearColor(1,0,1,1);
			glClear(GL_COLOR_BUFFER_BIT);

			for (Layer* layer : m_LayerStack) {
				layer->OnUpdate();
			}
			auto [x, y] = Input::GetMousePostion();
			YT_CORE_TRACE("{0},{1}",x, y);
			m_Window->OnUpdate();
		}
	}
	void Application::PushLayer(Layer* layer) {
		m_LayerStack.PushLayer(layer);
		layer->OnAttach();
	}
	void Application::PushOverlay(Layer* layer) {
		m_LayerStack.PushOverlay(layer);
		layer->OnDetach();
	}
}

测试：

小改动：

Core.h：

#pragma once
//用于dll的宏
#ifdef YT_PLATFORM_WINDOWS
#ifdef YT_BUILD_DLL
#define YOTO_API __declspec(dllexport) 
#else
#define YOTO_API __declspec(dllimport) 

#endif // DEBUG
#else
#error YOTO_ONLY_SUPPORT_WINDOWS
#endif // YOTO_PLATFORM_WINDOWS

#ifdef YT_DEBUG
#define YT_ENABLE_ASSERTS
#endif

#ifdef YT_ENABLE_ASSERTS
#define YT_CLIENT_ASSERT(x,...) {if(!(x)){YT_CLIENT_ERROR("断言错误：{0}",__VA_ARGS__);__debugbreak();}}
#define YT_CORE_ASSERT(x,...) {if(!(x)){YT_CORE_ERROR("断言错误：{0}",__VA_ARGS__);__debugbreak();}}
#else
#define YT_CLIENT_ASSERT(x,...)
#define YT_CORE_ASSERT(x,...)

#endif // YT_ENABLE_ASSERTS



#define BIT(x)(1<<x)
//绑定事件定义
#define YT_BIND_EVENT_FN(fn) std::bind(&fn, this, std::placeholders::_1)

SRC下的premake5.lua：

workspace "YOTOEngine"		-- sln文件名
	architecture "x64"	
	configurations{
		"Debug",
		"Release",
		"Dist"
	}
startproject "Sandbox"
-- https://github.com/premake/premake-core/wiki/Tokens#value-tokens
-- 组成输出目录:Debug-windows-x86_64
outputdir = "%{cfg.buildcfg}-%{cfg.system}-%{cfg.architecture}"
-- 包含相对解决方案的目录
IncludeDir={}
IncludeDir["GLFW"]="YOTOEngine/vendor/GLFW/include"
IncludeDir["Glad"]="YOTOEngine/vendor/Glad/include"
IncludeDir["ImGui"] ="YOTOEngine/vendor/imgui"
--项目中包含某包
include "YOTOEngine/vendor/GLFW"
include "YOTOEngine/vendor/Glad"
include "YOTOEngine/vendor/imgui"

project "YOTOEngine"		--YOTOEngine项目
	location "YOTOEngine"--在sln所属文件夹下的YOTOEngine文件夹
	kind "SharedLib"--dll动态库
	language "C++"
	targetdir ("bin/" .. outputdir .. "/%{prj.name}") -- 输出目录
	objdir ("bin-int/" .. outputdir .. "/%{prj.name}")-- 中间目录

	staticruntime "Off"

	pchheader "ytpch.h"
	pchsource "YOTOEngine/src/ytpch.cpp"
	-- 包含的所有h和cpp文件
	files{
		"%{prj.name}/src/**.h",
		"%{prj.name}/src/**.cpp"
	}
	-- 包含目录
	includedirs{
		"%{prj.name}/src",
		"%{prj.name}/vendor/spdlog-1.x/include",
		"%{IncludeDir.GLFW}",
		"%{IncludeDir.Glad}",
		"%{IncludeDir.ImGui}"
	}
	links{
		"GLFW",-- GLFW.lib库链接到YOTOEngine项目中
		"Glad",-- Glad.lib库链接到YOTOEngine项目中
		"ImGui",-- ImGui.lib库链接到YOTOEngine项目中
		"opengl32.lib"
	}
	-- 如果是window系统
	filter "system:windows"
		cppdialect "C++17"
		-- On:代码生成的运行库选项是MTD,静态链接MSVCRT.lib库;
		-- Off:代码生成的运行库选项是MDD,动态链接MSVCRT.dll库;打包后的exe放到另一台电脑上若无这个dll会报错
		systemversion "latest"	-- windowSDK版本
		-- 预处理器定义
		defines{
			"YT_PLATFORM_WINDOWS",
			"YT_BUILD_DLL",
			-- "YT_ENABLE_ASSERTS",
			"GLFW_INCLUDE_NONE"-- 让GLFW不包含OpenGL
		}
		-- 编译好后移动Hazel.dll文件到Sandbox文件夹下
		postbuildcommands{
			("{COPY} %{cfg.buildtarget.relpath} ../bin/" .. outputdir .. "/Sandbox")
		}
	-- 不同配置下的预定义不同
	filter "configurations:Debug"
		defines "YT_DEBUG"
		runtime "Debug"
		symbols "On"

	filter "configurations:Release"
		defines "YT_RELEASE"
		runtime "Release"
		optimize "On"

	filter "configurations:Dist"
		defines "YT_DIST"
		runtime "Release"
		optimize "On"

project "Sandbox"
	location "Sandbox"
	kind "ConsoleApp"
	language "C++"
	staticruntime "Off"
	targetdir ("bin/" .. outputdir .. "/%{prj.name}")
	objdir ("bin-int/" .. outputdir .. "/%{prj.name}")

	files{
		"%{prj.name}/src/**.h",
		"%{prj.name}/src/**.cpp"
	}
	-- 同样包含spdlog头文件
	includedirs{
		"YOTOEngine/vendor/spdlog-1.x/include",
		"YOTOEngine/src"
	}
	-- 引用YOTOEngine
	links{
		"YOTOEngine",
		"GLFW",
		"opengl32.lib"
	}

	filter "system:windows"
		cppdialect "C++17"
		systemversion "latest"

		defines{
			"YT_PLATFORM_WINDOWS"
		}

	filter "configurations:Debug"
		defines "YT_DEBUG"
		runtime "Debug"
		symbols "On"

	filter "configurations:Release"
		defines "YT_RELEASE"
		runtime "Release"
		optimize "On"

	filter "configurations:Dist"
		defines "YT_DIST"
		runtime "Release"
		optimize "On"