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C++使用MIDI库实现演奏晴天

作者：TwilightLemon

这篇文章主要为大家详细介绍了C++如何使用MIDI库实现演奏晴天歌曲,文中的示例代码讲解详细,具有一定的借鉴价值,感兴趣的小伙伴可以了解下

前言

那些在MIDI库里徘徊的十六分音符

终究没能拼成告白的主歌

我把周杰伦的《晴天》写成C++的类

在每个midiEvent里埋藏故事的小黄花

调试器的断点比初恋更漫长

而青春不过是一串未导出的cmake工程文件

在堆栈溢出的夜晚

终将明白

有些旋律永远停在#pragma once的注释里

有些人永远停在未定义的引用里

或许你我的心跳终归运行在不同的时钟频率

却愿始终记得如何编译出一场永不落幕的晴天

--题记

就像在题记里说的一样，这是一个从未导出成功的工程文件。

所以如果你也想听听，可以在PowerShell里运行以下指令：

git clone https://github.com/TwilightLemon/SunnyDays
cd SunnyDays
mkdir build
cd build
cmake .. -G "MinGW Makefiles"
mingw32-make
./SunnyDays.exe

没环境？巧了，她也如是说。

幸运的话能得到以下效果：

下面来简单讲讲如何使用C++和MIDI库作曲吧。

开始工作

1. 引入MIDI库和相关控制类

在CMakeLists.txt中：

target_link_libraries(SunnyDays winmm)

在MIDIHelper.h中：

#include <windows.h>
#pragma comment(lib,"winmm.lib")

定义Scale(音阶), Instrument(乐器, 仅包括部分)等枚举。我把Drum单独提了出来。

enum Scale
{
    X1 = 36, X2 = 38, X3 = 40, X4 = 41, X5 = 43, X6 = 45, X7 = 47,
    L1 = 48, L2 = 50, L3 = 52, L4 = 53, L5 = 55, L6 = 57, L7 = 59,
    M1 = 60, M2 = 62, M3 = 64, M4 = 65, M5 = 67, M6 = 69, M7 = 71,
    H1 = 72, H2 = 74, H3 = 76, H4 = 77, H5 = 79, H6 = 81, H7 = 83,
    LOW_SPEED = 500, MIDDLE_SPEED = 400, HIGH_SPEED = 300,
    _ = 0XFF
};
enum Drum{
    BassDrum = 36, SnareDrum = 38, ClosedHiHat = 42, OpenHiHat = 46
};
enum Instrument{
    AcousticGrandPiano = 0, BrightAcousticPiano = 1,
    ElectricGrandPiano = 2, HonkyTonkPiano = 3,
    ElectricPiano1 = 4, ElectricPiano2 = 5
};

一些基础方法，包括初始化/关闭设备、设置参数、播放单个音符和播放和弦等。

void initDevice();
void closeDevice();
void setInstrument(int channel, int instrument);
void setVolume(int channel, int volume);

void PlayNote(HMIDIOUT handle, UINT channel, UINT note, UINT velocity);

void playChord(HMIDIOUT handle, UINT channel, UINT note1, UINT note2, UINT note3, UINT note4, UINT velocity);

void playChord(HMIDIOUT handle, UINT channel, UINT note1, UINT note2, UINT note3, UINT velocity);

在MIDIHelper.cpp中：

void initDevice(){
    midiOutOpen(&hMidiOut, 0, 0, 0, CALLBACK_NULL);
}

void closeDevice(){
    midiOutClose(hMidiOut);
}

void setInstrument(int channel,int instrument){
    if (channel > 15 || instrument > 127) return;
    DWORD message = 0xC0 | channel | (instrument << 8);
    midiOutShortMsg(hMidiOut, message);
}

void setVolume(int channel,int volume){
    if (channel > 15 || volume > 127) return;
    DWORD message = 0xB0 | channel | (7 << 8) | (volume << 16);
    midiOutShortMsg(hMidiOut, message);
}

//播放单个音符，note是音符，velocity是力度
void PlayNote(HMIDIOUT handle, UINT channel, UINT note, UINT velocity) {
    if (channel > 15 || note > 127 || velocity > 127) return;
    DWORD message = 0x90 | channel | (note << 8) | (velocity << 16);
    midiOutShortMsg(handle, message);
}

//四指和弦
void playChord(HMIDIOUT handle, UINT channel, UINT note1, UINT note2, UINT note3, UINT note4, UINT velocity){
    if (channel > 15 || note1 > 127 || note2 > 127 || note3 > 127 || note4 > 127 || velocity > 127) return;
    DWORD message1 = 0x90 | channel | (note1 << 8) | (velocity << 16);
    DWORD message2 = 0x90 | channel | (note2 << 8) | (velocity << 16);
    DWORD message3 = 0x90 | channel | (note3 << 8) | (velocity << 16);
    DWORD message4 = 0x90 | channel | (note4 << 8) | (velocity << 16);
    midiOutShortMsg(handle, message1);
    midiOutShortMsg(handle, message2);
    midiOutShortMsg(handle, message3);
    midiOutShortMsg(handle, message4);
}

//三指和弦
void playChord(HMIDIOUT handle, UINT channel, UINT note1, UINT note2, UINT note3, UINT velocity) {
    if (channel > 15 || note1 > 127 || note2 > 127 || note3 > 127 || velocity > 127) return;
    DWORD message1 = 0x90 | channel | (note1 << 8) | (velocity << 16);
    DWORD message2 = 0x90 | channel | (note2 << 8) | (velocity << 16);
    DWORD message3 = 0x90 | channel | (note3 << 8) | (velocity << 16);
    midiOutShortMsg(handle, message1);
    midiOutShortMsg(handle, message2);
    midiOutShortMsg(handle, message3);
}

2. 初始化和结束

先在头文件中定义一个全局MIDI句柄:

extern HMIDIOUT hMidiOut;

在入口处初始化MIDI设备并在结束时关闭：

HMIDIOUT hMidiOut;
int main() {
    initDevice();
    //...
    closeDevice();
    return 0;
}

初始化MIDI设备之后，为每一个乐器分配一个通道channel（0~15，通常9分配给打击类乐器,例如鼓组），控制音量volume，然后就可以开始演奏了。

自制简易乐谱

以Voice.cpp为例,定义一个数组为频谱，控制停顿和音符，遍历数组播放：

 namespace SunnyDays{
      int channelVoice=1;
      void playVoice(int note, int velocity){
          PlayNote(hMidiOut, channelVoice, note, velocity);
      }
      void voice(){
         Sleep(13100);//等待前奏
          int sleep = 390;
          int data[] =
                 {
                     //故事的小黄花
                     -90,
                     300,M5,M5,M1,M1,_,M2,M3,_,
                     //从出生那年就飘着
                     -90,
                     M5,M5,M1,M1,0,M2,M3,300,M2,M1,_,
                    //童年的荡秋千
                     -90,
                     300,M5,M5,M1,M1,_,M2,M3,_,
                     //随记忆一直晃到现在
                     -90,  
                     M3,_,500,M2,M3,M4,M3,M2,M4,M3,700,M2,700,_,
                     //...
                 }
         for (auto i : data) {
            if(i==-30){logTime("Enter chorus");continue;}//调试用
             if(i==-90){NextLyric(); continue;}
             if (i == 0) { sleep = 180; continue; }
             //...
             if (i == _) {
                 Sleep(390);
                 continue;
             }
 
             playVoice(i, 80);
             Sleep(sleep);
         }
     }
 }

打个鼓：

 namespace SunnyDays{
      int channelBassDrum=9;
  
      void playDrum(int note, int velocity, int duration){
          PlayNote(hMidiOut, channelBassDrum, note, velocity);
          if(duration>0) {
              Sleep(duration);
              PlayNote(hMidiOut, channelBassDrum, note, 0);
         }
     }
 
     void bassDrum(){
         Sleep(11260);
         cout<<"Drum Bass Start!"<<endl;
         playDrum(SnareDrum,100,180);
         playDrum(SnareDrum,100,210);
         playDrum(BassDrum, 100, 210);
         playDrum(SnareDrum,100,190);
         playDrum(BassDrum, 100, 210);
         playDrum(SnareDrum,100,200);
         playDrum(SnareDrum,100,200);
         playDrum(OpenHiHat,100,-1);
         Sleep(200);
         //...
     }
 }

简易副歌和弦，是从B站一位up主那里学的（已经忘记是哪位了qwq）：

 namespace SunnyDays {
      int channelChord=2;
      void chordLevel(int level,int sleep,int repeat=2,int vel=70){
          repeat--;
          int down=8;
        if(level==1){
            //一级和弦 加右指
              playChord(hMidiOut, channelChord, M1, M3, M5, L1, vel);
              while(repeat--) {
               Sleep(sleep);
                playChord(hMidiOut, channelChord, M1, M3, M5, vel - down);
            }
         }else if(level==3){
             //三级和弦 加右指
             playChord(hMidiOut, channelChord, M3, M5, M7, L3, vel);
            while(repeat--) {
                Sleep(sleep);
                playChord(hMidiOut, channelChord, M3, M5, M7, vel - down);
             }
         }
         //...
     }
     void chord(){
         Sleep(63724);
         int sleep=740;
        int data[]={
                //刮风这天 我试过握着你手
                 1,4,
                 6,4,
                //但偏偏 雨渐渐
                 4,2,
                5,2,
                 //大到我看你不见
                 1,4,
                 //还有多久 我才能
                 3,4,
                 //↑ 在你身边
                 6,4,
                 //↓ 等到放晴的那天
                 4,4,
                 //↑ 也许我会比较好一点
                 5,4,
                 //..
         }
         int count=sizeof(data)/sizeof(int);
        for(int i=0;i<count;i+=2){
             cout<<"chord "<<data[i]<<"  x"<<data[i+1]<<endl;
             chordLevel(data[i],sleep,data[i+1]);
             Sleep(sleep);
         }
         //...
     }
 }

合成演奏

我用了一个笨蛋方法，用多线程单独控制每一个通道，然后在主线程中调用：

int main(){
      //...
      initDevice();
     //设置音量
      setVolume(channelChord,80);
      setVolume(channelMainLine,80);
      setVolume(channelVoice,120);
      setVolume(channelBassDrum,80);
  
    //设置乐器（特定音色）
     setInstrument(channelChord,ElectricPiano1);
     setInstrument(channelMainLine,ElectricPiano1);
 
 
     system("pause");//按下回车，就开始啦
     beginLogger();
 
 
     thread t0(voice);
     thread t1(mainLine);
     thread t2(bassDrum);
     thread t3(chord);
     t0.join();
     t1.join();
     t2.join();
     t3.join();
 
     closeDevice();
     //...
 }

（最后叠个甲，俺不懂音乐制作，更不会什么C++）

到此这篇关于C++使用MIDI库实现演奏晴天的文章就介绍到这了,更多相关C++ MIDI演奏音乐内容请搜索脚本之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持脚本之家！

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