/// <summary>
/// Called by the automation form to change the lobe type
/// </summary>
/// <param name="_type"></param>
public void SetLobeType( LobeModel.LOBE_TYPE _type )
{
switch ( _type ) {
case LobeModel.LOBE_TYPE.MODIFIED_PHONG: radioButtonAnalyticalPhong.Checked = true; break;
case LobeModel.LOBE_TYPE.MODIFIED_PHONG_ANISOTROPIC: radioButtonAnalyticalPhongAnisotropic.Checked = true; break;
case LobeModel.LOBE_TYPE.BECKMANN: radioButtonAnalyticalBeckmann.Checked = true; break;
case LobeModel.LOBE_TYPE.GGX: radioButtonAnalyticalGGX.Checked = true; break;
}
}
void PerformLobeFitting( float3 _incomingDirection, float _theta, bool _computeInitialThetaUsingCenterOfMass, float _roughness, float _IOR, float _scale, float _flatteningFactor, float _MaskingImportance, float _OversizeFactor, int _scatteringOrder, bool _reflected )
{
checkBoxShowAnalyticalLobe.Checked = true;
// Read back histogram to CPU for fitting
m_Tex_LobeHistogram_CPU.CopyFrom( _reflected ? m_Tex_LobeHistogram_Reflected : m_Tex_LobeHistogram_Transmitted );
// Initialize lobe model
m_lobeModel = new LobeModel();
m_lobeModel.ParametersChanged += ( double[] _parameters ) => {
UpdateLobeParameters( _parameters, _reflected );
};
double[,] histogramData = LobeModel.HistogramTexture2Array( m_Tex_LobeHistogram_CPU, _scatteringOrder );
m_lobeModel.InitTargetData( histogramData );
LobeModel.LOBE_TYPE lobeType = radioButtonAnalyticalPhong.Checked ? LobeModel.LOBE_TYPE.MODIFIED_PHONG :
(radioButtonAnalyticalPhongAnisotropic.Checked ? LobeModel.LOBE_TYPE.MODIFIED_PHONG_ANISOTROPIC :
(radioButtonAnalyticalBeckmann.Checked ? LobeModel.LOBE_TYPE.BECKMANN : LobeModel.LOBE_TYPE.GGX));
if ( _computeInitialThetaUsingCenterOfMass ) {
// Optionally override theta to use the direction of the center of mass
// (quite intuitive to start by aligning our lobe along the main simulated lobe direction!)
float3 towardCenterOfMass = m_lobeModel.CenterOfMass.Normalized;
_theta = (float) Math.Acos( towardCenterOfMass.z );
// _scale = 2.0 * m_centerOfMass.Length; // Also assume we should match the simulated lobe's length
_flatteningFactor = lobeType == LobeModel.LOBE_TYPE.MODIFIED_PHONG ? 0.5f : 1.0f; // Start from a semi-flattened shape so it can choose either direction...
_scale = 0.01f * m_lobeModel.CenterOfMass.Length; // In fact, I realized the algorithm converged much faster starting from a very small lobe!! (~20 iterations compared to 200 otherwise, because the gradient leads the algorithm in the wrong direction too fast and it takes hell of a time to get back on tracks afterwards if we start from too large a lobe!)
}
m_lobeModel.InitLobeData( lobeType, _incomingDirection, _theta, _roughness, _scale, _flatteningFactor, _MaskingImportance, _OversizeFactor, checkBoxUseCenterOfMassForBetterFitting.Checked );
// if ( !checkBoxUseCenterOfMassForBetterFitting.Checked ) {
// m_Fitter.SuccessTolerance = 1e-4;
// m_Fitter.GradientSuccessTolerance = 1e-4;
// }
// Peform fitting
m_Fitter.Minimize( m_lobeModel );
panelOutput.Invalidate();
}