跟着cherno手搓游戏引擎【7】Input轮询-编程知识

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windowinline 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YOTOEnginelinks{"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"