c++ - 构建和运行应用程序时出现奇怪的噪音

Question

我正在学习 SDL 2.0 教程，因为自从我学习 1.2 后情况发生了很大变化。我现在有一个非常简单的程序，只有一个窗口类、一个应用程序类和一个纹理类。当我调试和编译我的程序时，我从我的扬声器中听到类似高音调的嗡嗡声。如果我从调试文件夹运行已编译的 .exe 文件，也会发生这种情况。

我不知道如何解决这个问题。因为它似乎只是我的程序，并且发生在 .exe 文件上，所以我怀疑这是 visual studio 的错。虽然我不是真正的大程序员，但这只是一种爱好，所以也许是。这对我的程序来说是良性的(到目前为止，因为它很小)，但它很烦人。有人知道为什么我的扬声器开始发出噪音吗？

提前谢谢你。

我将在下面发布我的代码，但我没有对 SDL Audio API 做任何事情。

源文件

#include <Windows.h>
#include "KApp.h"


const int winW = 800;
const int winH = 600;


int main(int argc, char** argv ) {

    KApp ThisApp;

    ThisApp.Run( winW, winH);

    return 0;
}

KApp.h

#ifndef __KAPP_H__
#define __KAPP_H__

#include <SDL.h>
#include <vector>

#include "Window.h"
#include "KTexture.h"


class KApp {

private:

    enum States {
        INIT = 0,
        RUNNING,
        PAUSED,
        HALTED,

    };

    States GameState;
    Window* MainWindow;
    std::vector<KTexture*> Textures;

public:

    KApp();
    ~KApp();

    void Run(const int &,const int &);
    void Handle(SDL_Event* Event);
    void Update();
    void Render();

    void CleanUp();

};



#endif 

KApp.cpp

#include "KApp.h"


KApp::KApp() {

    GameState = INIT;
    MainWindow = NULL;

    if(SDL_Init(SDL_INIT_EVERYTHING) < 0 ) { 
        exit(0x1);
    }

    //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_DEPTH_SIZE,        16);
    //SDL_GL_SetAttribute(SDL_GL_BUFFER_SIZE,       32);

    //SDL_GL_SetAttribute(SDL_GL_ACCUM_RED_SIZE,     8);
    //SDL_GL_SetAttribute(SDL_GL_ACCUM_GREEN_SIZE,   8);
    //SDL_GL_SetAttribute(SDL_GL_ACCUM_BLUE_SIZE,    8);
    //SDL_GL_SetAttribute(SDL_GL_ACCUM_ALPHA_SIZE,   8);

    //SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, 1);
    //SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, 2);

    return;

}

KApp::~KApp() {

    if( MainWindow != NULL ) {
        delete MainWindow;
        MainWindow = NULL;
    }

    for( std::vector<KTexture*>::iterator it = Textures.begin(); it != Textures.end(); it++ ) {
        delete *it;
    }
    Textures.clear();

    SDL_Quit();

    return;
}

void KApp::Handle(SDL_Event* Event) {
    if(Event->type == SDL_QUIT) {
        GameState = HALTED;
    }
}

void KApp::CleanUp() {

}

void KApp::Render() {
    MainWindow->Render();
}


void KApp::Run(const int& w,const int& h) {

    MainWindow = new Window(w,h,"KApp Main Window");
    if(!MainWindow->Create()) {
        exit(1);
    }

    Textures.push_back(new KTexture("E:/Pictures/BKG.bmp"));
    Textures[0]->Optimize(MainWindow->Surface());

    MainWindow->Blit(Textures[0]->Surface());

    GameState = RUNNING;
    SDL_Event Event;

    while(GameState == RUNNING) {
        while(SDL_PollEvent(&Event)) {
            Handle(&Event);
        }

        Update();
        Render();
    }   

    CleanUp();

}

void KApp::Update() {}

KWindow.h

#ifndef __WINDOW_H__
#define __WINDOW_H__

#include <SDL.h>
#include <gl/gl.h>
#include <gl/glu.h>
#include <string>


class Window {

private:
    int Width;
    int Height;
    std::string Title;

    SDL_Window* WNDW;
    SDL_Surface* SFC;


public:
    Window() : Width(800),Height(600),Title("Window"),WNDW(NULL),SFC(NULL) {}
    Window(int w, int h, std::string title) : Width(w),Height(h),Title(title),WNDW(NULL),SFC(NULL) {}
    ~Window() { 
        if(WNDW != NULL) {
            SDL_DestroyWindow(WNDW);
            WNDW = NULL;
        }

    }

    bool Create() {

        if( WNDW != NULL ) {
            return true;
        }

        WNDW = SDL_CreateWindow( Title.c_str(), SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, Width, Height, SDL_WINDOW_SHOWN );
        if( WNDW == NULL ) {
            return false;
        }

        SFC = SDL_GetWindowSurface( WNDW );
        SDL_FillRect ( SFC , NULL, SDL_MapRGB( SFC->format, 0x00, 0x00, 0x00 ) );
        SDL_UpdateWindowSurface( WNDW );


        //if((Surface = SDL_SetVideoMode(Width,Height,32, SDL_HWSURFACE | SDL_GL_DOUBLEBUFFER | SDL_OPENGL | SDL_RESIZABLE )) == NULL) {
        //  return false;
        //}
        /*
        glClearColor(0, 0, 0, 0);
        glClearDepth(1.0f);
        glViewport(0, 0, Width, Height);
        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        glOrtho(0, Width, Height, 0, 1, -1);
        glMatrixMode(GL_MODELVIEW);
        glEnable (GL_BLEND); 
        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
        glLoadIdentity();
        */

        return true;
    }

    void Clear() {
        SDL_FillRect ( SFC , NULL, SDL_MapRGB( SFC->format, 0x00, 0x00, 0x00 ) );
        SDL_UpdateWindowSurface( WNDW );
    }

    void Blit(SDL_Surface* Surf) {
        SDL_BlitSurface(Surf, NULL, SFC, NULL);
    }

    void BlitScaled(SDL_Surface* Surf, int x, int y, int w, int h) {
        SDL_Rect MyRectum;
        MyRectum.x = x;
        MyRectum.y = y;
        MyRectum.w = w;
        MyRectum.h = h;
        SDL_BlitScaled(Surf, NULL, SFC, &MyRectum);
    }

    void Render() {
        SDL_UpdateWindowSurface( WNDW );
    }

    SDL_Surface* Surface() {
        return SFC;
    }

};

#endif

KTexture.h

#ifndef __KTEXTURE_H__
#define __KTEXTURE_H__

#include <SDL.h>
#include <string>

class KTexture {

private:
    SDL_Surface* Texture;

public:

    KTexture() : Texture(NULL) {}
    KTexture( std::string path ) : Texture(NULL) {
        Load(path);
    }

    ~KTexture() {
        if( Texture != NULL ) {
            SDL_FreeSurface(Texture);
            Texture = NULL;
        }
    }

    bool Load( std::string path ) {

        Texture = SDL_LoadBMP( path.c_str() );
        if(Texture == NULL) {
            return false;
        }

        return true;
    }

    void Render() {
        Render(0,0);
    }

    void Render(int x, int y) {


    }

    SDL_Surface* Surface() {
        return Texture;
    }

    bool Optimize(SDL_Surface* For) {
        SDL_Surface* nsurf = SDL_ConvertSurface( Texture, For->format, NULL);
        if( nsurf == NULL) {
            return false;
        }

        SDL_FreeSurface(Texture);
        Texture = nsurf;

        return true;

    }

};


#endif 

编辑 修复。将此添加到 KApp::Run() 函数

Uint32 Time = SDL_GetTicks();

GameState = RUNNING;
SDL_Event Event;

while(GameState == RUNNING) {
    while(SDL_PollEvent(&Event)) {
        Handle(&Event);
    }

    Update();
    if( SDL_GetTicks() > Time + 300) {
        Render();
        Time = SDL_GetTicks();
    }
    else
    {
        SDL_Delay(1);
    }
}   

Answer 1

当您的应用程序以非常高的帧速率运行时，我已经看到了这种情况。尖锐的声音通常来自显卡。

尝试在代码中启用垂直同步或限制应用程序的帧率。