void CHLSLTessellator::TriHLSLProcessTessFactors()

in d3d/archive/images/d3d11/tessellator.cpp [2429:2534]
91 lines of code
19 McCabe index (conditional complexity)

void CHLSLTessellator::TriHLSLProcessTessFactors( float tessFactor_Ueq0, float tessFactor_Veq0, float tessFactor_Weq0, 
                                  float insideTessFactorScale )
{
    if( !(tessFactor_Ueq0 > 0) || // NaN will pass
        !(tessFactor_Veq0 > 0) ||
        !(tessFactor_Weq0 > 0) )
    {
        m_LastUnRoundedComputedTessFactors[0] = tessFactor_Ueq0;
        m_LastUnRoundedComputedTessFactors[1] = tessFactor_Veq0;
        m_LastUnRoundedComputedTessFactors[2] = tessFactor_Weq0;
        m_LastUnRoundedComputedTessFactors[3] = 
        m_LastComputedTessFactors[0] = 
        m_LastComputedTessFactors[1] = 
        m_LastComputedTessFactors[2] = 
        m_LastComputedTessFactors[3] = 0;
        return;
    }

    CleanupFloatTessFactor(tessFactor_Ueq0); // clamp to [1.0f..INF], NaN->1.0f
    CleanupFloatTessFactor(tessFactor_Veq0);
    CleanupFloatTessFactor(tessFactor_Weq0);

    // Save off TessFactors so they can be returned to app
    m_LastUnRoundedComputedTessFactors[0] = tessFactor_Ueq0;
    m_LastUnRoundedComputedTessFactors[1] = tessFactor_Veq0;
    m_LastUnRoundedComputedTessFactors[2] = tessFactor_Weq0;

    // Process outside TessFactors
    float outsideTessFactor[TRI_EDGES] = {tessFactor_Ueq0, tessFactor_Veq0, tessFactor_Weq0};
    int edge;
    if( Pow2Partitioning() || IntegerPartitioning() )
    {
        for( edge = 0; edge < TRI_EDGES; edge++ )
        {
            RoundUpTessFactor(outsideTessFactor[edge]); // for pow2 this rounds to pow2
            ClampTessFactor(outsideTessFactor[edge]); // clamp unbounded user input based on tessellation mode
        }
    }
    else
    {
        for( edge = 0; edge < TRI_EDGES; edge++ )
        {
            ClampTessFactor(outsideTessFactor[edge]); // clamp unbounded user input based on tessellation mode
        }
    }
    
    // Compute inside TessFactor
    float insideTessFactor;
    switch( m_insideTessFactorReduction )
    {
    case D3D11_TESSELLATOR_REDUCTION_MIN:
        insideTessFactor = fmin(fmin(tessFactor_Ueq0,tessFactor_Veq0),tessFactor_Weq0);
        break;
    case D3D11_TESSELLATOR_REDUCTION_MAX:
        insideTessFactor = fmax(fmax(tessFactor_Ueq0,tessFactor_Veq0),tessFactor_Weq0);
        break;
    case D3D11_TESSELLATOR_REDUCTION_AVERAGE:
        insideTessFactor = (tessFactor_Ueq0 + tessFactor_Veq0 + tessFactor_Weq0) / 3;
        break;
    }

    // Scale inside TessFactor based on user scale factor.
    ClampFloatTessFactorScale(insideTessFactorScale); // clamp scale value to [0..1], NaN->0
    insideTessFactor = insideTessFactor*fmin(FLOAT_ONE,insideTessFactorScale);

    ClampTessFactor(insideTessFactor); // clamp reduction + scale result that is based on unbounded user input
    m_LastUnRoundedComputedTessFactors[3] = insideTessFactor;// Save off TessFactors so they can be returned to app
    TESSELLATOR_PARITY parity;
    if( Pow2Partitioning() || IntegerPartitioning() )
    {
        RoundUpTessFactor(insideTessFactor);
        parity = (isEven(insideTessFactor) || (FLOAT_ONE == insideTessFactor))
                                        ? TESSELLATOR_PARITY_EVEN : TESSELLATOR_PARITY_ODD;
    }
    else
    {
        parity = m_originalParity;
    }

    if( (TESSELLATOR_PARITY_ODD == parity) &&
        (insideTessFactor < FLOAT_THREE))
    {
        // To prevent snapping on edges, the "picture frame" comes
        // in using avg or max (and ignore inside TessFactor scaling) until it is at least 3.
        if(D3D11_TESSELLATOR_REDUCTION_MAX == m_insideTessFactorReduction)
        {
            insideTessFactor = fmin(FLOAT_THREE,fmax(tessFactor_Ueq0,fmax(tessFactor_Veq0,tessFactor_Weq0)));
        }
        else
        {
            insideTessFactor = fmin(FLOAT_THREE,(tessFactor_Ueq0 + tessFactor_Veq0 + tessFactor_Weq0) / 3);
        }
        ClampTessFactor(insideTessFactor); // clamp reduction result that is based on unbounded user input
        m_LastUnRoundedComputedTessFactors[3] = insideTessFactor;// Save off TessFactors so they can be returned to app
        if( IntegerPartitioning())
        {
            RoundUpTessFactor(insideTessFactor);
        }
    }

    // Save off TessFactors so they can be returned to app
    m_LastComputedTessFactors[0] = outsideTessFactor[Ueq0];
    m_LastComputedTessFactors[1] = outsideTessFactor[Veq0];
    m_LastComputedTessFactors[2] = outsideTessFactor[Weq0];
    m_LastComputedTessFactors[3] = insideTessFactor;
}