SDL事件处理延迟

按键之间有一个主要(1-2秒)延迟

#include <iostream>
#include "src/Input/InputManager.h"
#include "src/Graphics/Display.h"
#define LOG(x) std::cout << x << std::endl;
using namespace Rambug;
int main(int arc, char** argv)
{
    Graphics::Display display(900, 600, "Rambug Engine Tester", true);
    display.createDisplay();
    SDL_Event event;
    Input::InputManager inputManager;
    // "Game" Loop
    while (!display.isClosed())
    {
        display.update();
        glClearColor(0.0f, 0.02f, 0.5f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
        while (SDL_PollEvent(&event))
        {
            if (event.type == SDL_KEYDOWN)
            {
                std::cout << "Keydowner" << std::endl;
            }
            if (event.type == SDL_KEYUP)
            {
                std::cout << "Keyupper" << std::endl;
            }
        }
    //  inputManager.update();
    }
    display.destroyDisplay();
    system("PAUSE");
    return 0;
}

这是Display.cpp，当我运行相同的代码(SDL_KEYDOWN, SDL_KEYUP)时，它运行完美，没有任何延迟，我只是在那里运行SDL_QUIT。

#include "Display.h"
namespace Rambug
{
    namespace Graphics
    {
        Display::Display(int width, int height, std::string title, bool log)
        {
            m_displayWidth = width;
            m_displayHeight = height;
            m_displayTitle = title;
            m_log = log;
            m_window = nullptr;
        }
        Display::Display()
        {
        }
        Display::~Display()
        {
        }
        void Display::createDisplay()
        {
            // Initialize SDL
            SDL_Init(SDL_INIT_EVERYTHING);
            // Setting attributes to our window
            SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 8);
            SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 8);
            SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 8);
            SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 8);
            SDL_GL_SetAttribute(SDL_GL_BUFFER_SIZE, 32);
            SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
            // Create window
            m_window = SDL_CreateWindow((m_displayTitle.c_str()), SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, m_displayWidth, m_displayHeight, SDL_WINDOW_OPENGL);
            // Error Check Window
            if (m_window == nullptr)
            {
                if (m_log)
                    std::cerr << "Window could not be created!" << std::endl;
            }
            else
            {
                if (m_log)
                    std::cout << "Window Created Successfully With SDL!" << std::endl;
            }
            // Create OpenGL Context
            m_glContext = SDL_GL_CreateContext(m_window);
            // Initialize GLEW
            glewExperimental = GL_TRUE;
            GLenum status = glewInit();
            if (glewExperimental)
            {
                if (m_log)
                    std::cout << "Glew Experimental: On" << std::endl;
            }
            // Error Check GLEW
            if (status != GLEW_OK)
            {
                if (m_log)
                {
                    std::cerr << "GLEW could not be initialized!" << std::endl;
                }
            }
            else
            {
                if (m_log)
                {
                    std::cout << "GLEW Was Initilized Successfully!" << std::endl;
                }
            }
            // Log OpenGL Version Number
            if (m_log)
            {
                std::cout << "Using OpenGL Version: " << glGetString(GL_VERSION) << std::endl;
            }
            m_closed = false;
        }
        void Display::destroyDisplay()
        {
            SDL_GL_DeleteContext(m_glContext);
            SDL_DestroyWindow(m_window);
            SDL_Quit();
        }
        void Display::update()
        {
            SDL_GL_SwapWindow(m_window);
            // Check for Input
            while (SDL_PollEvent(&m_sdlEvent))
            {
                if (m_sdlEvent.type == SDL_QUIT)
                {
                    m_closed = true;
                }
            }
        }
        bool Display::isClosed()
        {
            return m_closed;
        }
    }
}

我还尝试了一个Input管理器类，但这是同样的问题:延迟。更新方法就是我在main.cpp中调用的方法(我相信它被注释掉了)

#include "InputManager.h"
#include <iostream>
#define LOG(x) std::cout << x << std::endl;
namespace Rambug
{
    namespace Input
    {
        InputManager::InputManager()
        {
        }
        InputManager::~InputManager()
        {
        }
        void InputManager::keyPressed(unsigned int keyCode)
        {
            m_keyMap[keyCode] = true;
        }
        void InputManager::keyReleased(unsigned int keyCode)
        {
            m_keyMap[keyCode] = false;
        }
        bool InputManager::isKeyDown(unsigned int keyCode)
        {
            auto it = m_keyMap.find(keyCode);
            if (it != m_keyMap.end())
            {
                 return it->second;
            } 
            else
            {
                return false;
            } 
        }
        void InputManager::update()
        {
            while (SDL_PollEvent(&m_event))
            {
                switch (m_event.type)
                {
                case SDL_KEYDOWN:
                    LOG("SDL_KEYDOWN");
                    keyPressed(m_event.key.keysym.sym);
                    break;
                case SDL_KEYUP:
                    LOG("SDL_KEYUP");
                    keyReleased(m_event.key.keysym.sym);
                    break;
                }
            }
        }
    }
}

所以InputManager和main.cpp有很大的延迟，而Display.cpp运行得很好。是因为我不能运行SDL_PollEvents两次吗?