C / C++ / MFC

TheScientistIsDead wrote:

Isn't there an issue regarding threads and access to process-wide variables/data

TheScientistIsDead wrote:

Will I be able to kill a thread, while its in the middle of doing some kind of processing, from the main thread?

TheScientistIsDead wrote:

And can I change the flag's status (if quit is posted after I initialize the new thread)

// we have a thread handle, hThread and a shared LONG variable lQuit which is zero until it's time to quit
InterlockedExchange(&lQuit, 1);
::WaitForSingleObject(hThread, INFINITE);

// do stuff
if (lQuit) ExitThread(0);
// do some more stuff
if (lQuit) ExitThread(0);

TheScientistIsDead wrote:

I'm a little new to multi-threading.

csrss wrote:

PBYTE fValue = (BYTE *)malloc(dwSize * sizeof(DWORD));

#define  NtGetProcessHeap() (NtCurrentTeb()->PebBaseAddress->DefaultHeap)

char valueA = { 0x56, 0x61, 0x6c, 0x75, 0x65, 0x41, 0x00};
char valueB = { 0x56, 0x61, 0x6c, 0x75, 0x65, 0x42, 0x00};

DWORD dwSize = ((strlen(valueA) + strlen(valueB)) + 3);
LPBYTE fValue = (BYTE *)RtlAllocateHeap(NtGetProcessHeap(),0,dwSize);
memset(fValue , 0, dwSize);
memcpy(fValue , valueA, strlen(valueA) + 1);
memcpy(fValue + strlen(valueA) + 1, valueB, strlen(valueB) + 1);
RegSetValueEx(hk, TEXT("somekey"), 0, REG_MULTI_SZ, (LPBYTE) fValue ,(DWORD) dwSize);
RtlFreeHeap(NtGetProcessHeap(), 0, fValue );

#define WS_OVERLAPPEDWINDOW (WS_OVERLAPPED     | \
                             WS_CAPTION        | \
                             WS_SYSMENU        | \
                             WS_THICKFRAME     | \
                             WS_MINIMIZEBOX    | \
                             WS_MAXIMIZEBOX)

newRed = ( baseAlpha * baseRed + paintAlpha * paintRed ) / (baseAlpha + paintAlpha);
newGreen = ...
newBlue = ...
newAlpha = 1 - (1-baseAlpha)*(1-paintAlpha);

afterRed = topAlpha * topRed + (1-topAlpha) * bottomRed;

public override ColorBgra Apply(ColorBgra color)
{
    int a = blendColor.A;
    int invA = 255 - a;

    int r = ((color.R * invA) + (blendColor.R * a)) / 256;
    int g = ((color.G * invA) + (blendColor.G * a)) / 256;
    int b = ((color.B * invA) + (blendColor.B * a)) / 256;
    byte a2 = ComputeAlpha(color.A, blendColor.A);

    return ColorBgra.FromBgra((byte)b, (byte)g, (byte)r, a2);
}

public static ColorBgra Blend(ColorBgra ca, ColorBgra cb, byte cbAlpha)
{
    uint caA = (uint)Utility.FastScaleByteByByte((byte)(255 - cbAlpha), ca.A);
    uint cbA = (uint)Utility.FastScaleByteByByte(cbAlpha, cb.A);
    uint cbAT = caA + cbA;

    uint r;
    uint g;
    uint b;

    if (cbAT == 0)
    {
        r = 0;
        g = 0;
        b = 0;
    }
    else
    {
        r = ((ca.R * caA) + (cb.R * cbA)) / cbAT;
        g = ((ca.G * caA) + (cb.G * cbA)) / cbAT;
        b = ((ca.B * caA) + (cb.B * cbA)) / cbAT;
    }

    return ColorBgra.FromBgra((byte)b, (byte)g, (byte)r, (byte)cbAT);
}

public static int FastScaleByteByByte(byte a, byte b)
{
    int r1 = a * b + 0x80;
    int r2 = ((r1 >> 8) + r1) >> 8;
    return (byte)r2;
}

public static int FastScaleByteByByte(byte a, byte b)
{
   int r1 = a * b + 0x80;
   int r2 = ((r1 >> 8) + r1) >> 8;
   return (byte)r2;
}

public static int FastScaleByteByByte(byte a, byte b)
{
   int r1 = a * b + 128;  // 128 is half if 256, and is the equivalent of adding 0.5 before rounding a number to
   int r2 = ((r1 / 256) + r1) / 256;
   return (byte)r2;
}

Iain Clarke wrote:

You can peek at their math... and then prove me correct, obviously!