void CHWTessellator::ComputeTessFactorContext()

in d3d/archive/images/d3d11/tessellator.cpp [1700:1750]
50 lines of code
9 McCabe index (conditional complexity)

void CHWTessellator::ComputeTessFactorContext( FXP fxpTessFactor, TESS_FACTOR_CONTEXT& TessFactorCtx )
{
    FXP fxpHalfTessFactor = (fxpTessFactor+1/*round*/)/2;
    if( Odd() || (fxpHalfTessFactor == FXP_ONE_HALF)) // fxpHalfTessFactor == 1/2 if TessFactor is 1, but we're pretending we are even.
    {
        fxpHalfTessFactor += FXP_ONE_HALF;
    }
    FXP fxpFloorHalfTessFactor = fxpFloor(fxpHalfTessFactor);
    FXP fxpCeilHalfTessFactor = fxpCeil(fxpHalfTessFactor);
    TessFactorCtx.fxpHalfTessFactorFraction = fxpHalfTessFactor - fxpFloorHalfTessFactor;
    //CleanseParameter(TessFactorCtx.fxpHalfTessFactorFraction);
    TessFactorCtx.numHalfTessFactorPoints = (fxpCeilHalfTessFactor>>FXP_FRACTION_BITS); // for EVEN, we don't include the point always fixed at the midpoint of the TessFactor
    if( fxpCeilHalfTessFactor == fxpFloorHalfTessFactor )
    {
        TessFactorCtx.splitPointOnFloorHalfTessFactor =  /*pick value to cause this to be ignored*/ TessFactorCtx.numHalfTessFactorPoints+1;
    }
    else if( Odd() )
    {
        if( fxpFloorHalfTessFactor == FXP_ONE )
        {
            TessFactorCtx.splitPointOnFloorHalfTessFactor = 0;
        }
        else
        {
#ifdef ALLOW_XBOX_360_COMPARISON
            if( m_bXBox360Mode )
                TessFactorCtx.splitPointOnFloorHalfTessFactor = TessFactorCtx.numHalfTessFactorPoints-2;
            else
#endif
				TessFactorCtx.splitPointOnFloorHalfTessFactor = (RemoveMSB((fxpFloorHalfTessFactor>>FXP_FRACTION_BITS)-1)<<1) + 1;
        }
    }
    else
    {
#ifdef ALLOW_XBOX_360_COMPARISON
        if( m_bXBox360Mode )
            TessFactorCtx.splitPointOnFloorHalfTessFactor = TessFactorCtx.numHalfTessFactorPoints-1;
        else
#endif
			TessFactorCtx.splitPointOnFloorHalfTessFactor = (RemoveMSB(fxpFloorHalfTessFactor>>FXP_FRACTION_BITS)<<1) + 1;
    }
    int numFloorSegments = (fxpFloorHalfTessFactor * 2)>>FXP_FRACTION_BITS;
    int numCeilSegments = (fxpCeilHalfTessFactor * 2)>>FXP_FRACTION_BITS;
    if( Odd() )
    {
        numFloorSegments -= 1;
        numCeilSegments -= 1;
    }
    TessFactorCtx.fxpInvNumSegmentsOnFloorTessFactor = s_fixedReciprocal[numFloorSegments];
    TessFactorCtx.fxpInvNumSegmentsOnCeilTessFactor = s_fixedReciprocal[numCeilSegments];
}