fake_vsync

#include "stdafx.h"

//make vertical white bar(s) across an 80x50 console
void vbar(CHAR_INFO buff[4000], int pos){
    if (pos < 0 || pos > 79) {return;}
    const CHAR_INFO white = { ' ', BACKGROUND_RED | BACKGROUND_GREEN | BACKGROUND_BLUE | BACKGROUND_INTENSITY };
    const CHAR_INFO black = { ' ', 0 };

    for (int i = 0; i < 80; i++)    {   buff[i] = black;}
    buff[pos] = white;
    buff[(pos + 1) % 80] = white;
    buff[(pos + 3) % 80] = white;
    buff[(pos + 5) % 80] = white;

    CHAR_INFO* firstLine = buff;
    for (CHAR_INFO* curLine = &buff[80]; curLine < &buff[80 * 49 + 1]; curLine += 80)
    {   memcpy_s((void*)curLine, sizeof(CHAR_INFO) * 80, (void*)firstLine, sizeof(CHAR_INFO)*80);}
}

int _tmain(int argc, _TCHAR* argv[]){
    HANDLE hdl = GetStdHandle(STD_OUTPUT_HANDLE);
    CHAR_INFO buff[80 * 50];

    SetConsoleScreenBufferSize(hdl, { 80, 50 });
    SMALL_RECT recv = { 0, 0, 80, 50 };

    DWORD oldTime = GetTickCount();
    int pos = 0;
    SHORT yPos = 0;
    bool done = false;

    while (!done){
        CONST DWORD newTime = GetTickCount();

        if (newTime != oldTime)
        {   vbar(buff, pos);
            DWORD diffTime = newTime - oldTime;
            oldTime = newTime;
            pos = (pos + 1) % 80;
            WriteConsoleOutput(hdl, buff, { 80, 50 }, { 5, 0 }, &recv);

            yPos = (yPos + 1) % 50;
            printf_s("%04d", diffTime);
            SetConsoleCursorPosition(hdl, { 75, yPos });
        }

        if (_kbhit())
            {done = (_getch() == 27);}
    }

    return 0;
}