private void UpdateLightChart(LightSource light)
{
SpectralData data = light.SpectralPowerDistribution;
Series series = LightSourceChart.Series[0];
series.Points.Clear();
for (int wavelength = data.LowestWavelength, i = 0; wavelength <= data.HighestWavelength; wavelength += data.StepSize, i++)
{
series.Points.Add(new DataPoint((float)wavelength, data.WaveData[i]));
}
}
public void RecalculateColors(LightSource lightSource, Observer observer, bool clipInvisible)
{
foreach (ModelNode modelNode in this.ModelGraph)
{
modelNode.RecalculateColors(lightSource, observer, clipInvisible);
}
}
public void RecalculateColors(LightSource lightSource, Observer observer, bool clipInvisible)
{
try
{
// Calculate RGB values
this.MaterialRGB = Utilities.GetEquivalentRGB(this.Material);
// Calculate the tristimulus values.
this.FinalTristimulus = Utilities.CalculateTristimulusValues(lightSource, this.Material, observer, clipInvisible);
this.FinalRGB = Utilities.CalculateRGBfromXYZ(FinalTristimulus);
// Not sure why I'm having to do this, but for now sometimes the scene renders like a ghost, so make alpha 1.
this.FinalRGB = new Vector4(FinalRGB.X, FinalRGB.Y, FinalRGB.Z, 1f);
this.MaterialRGB = new Vector4(MaterialRGB.X, MaterialRGB.Y, MaterialRGB.Z, 1f);
}
catch (Exception e)
{
MessageBox.Show("Color calculations because " + e.Message);
throw;
}
}
/// <summary>
/// Read in all the light sources from the given file.
/// </summary>
/// <param name="fileName">Path to the data file.</param>
protected void ReadInLights(string fileName)
{
XmlDocument lightSourcesXml = new XmlDocument();
lightSourcesXml.Load(fileName);
foreach (XmlElement lightSourceXML in lightSourcesXml.GetElementsByTagName(XMLDataConstants.LightSource))
{
LightSource lightSource = new LightSource();
lightSource.Initialize(lightSourceXML);
this.LightSources.Add(lightSource);
}
}
/// <summary>
/// Calculate the tristimulus values for the given combination of light source, material and observer.
/// </summary>
/// <returns>A float array of size 3 containing X, Y and Z in each cell respectively.</returns>
public static Vector3 CalculateTristimulusValues(LightSource lightSource, Material material, Observer observer, bool clipInvisible = false)
{
// TODO: This may not be the most efficient of all approaches, make sure you change this to be more streamlined.
// Normalize spectra.
//
List<SpectralData> spectraBank = new List<SpectralData>();
spectraBank.Add(lightSource.SpectralPowerDistribution);
spectraBank.Add(material.ReflectanceDistribution);
spectraBank.Add(observer.ResponseSpectra[0]);
spectraBank.Add(observer.ResponseSpectra[1]);
spectraBank.Add(observer.ResponseSpectra[2]);
Utilities.NormalizeSpectra(spectraBank);
// Calculate the normalizing constant for tristimulus integration
//
float K = Utilities.TristimulusNormalizingConstant(lightSource, observer);
float summation;
int stepSize = lightSource.SpectralPowerDistribution.StepSize;
// The wave data we need is nested deep inside objects. So grab it into local arrays
// for convenience of coding.
//
float[] lightSourceData, materialData, observerXData, observerYData, observerZData;
if (clipInvisible)
{
// Find out what indexes correspond to wavelengths between 380 and 780 nm.
// Since the data is normalized, calculating based on 1 source should be enough.
int startIndex = (380 - lightSource.SpectralPowerDistribution.LowestWavelength) / lightSource.SpectralPowerDistribution.StepSize;
int count = (780 - 380) / lightSource.SpectralPowerDistribution.StepSize + 1;
// Sanity check
if (startIndex < 0)
{
throw new ArgumentException("wavelength data provided started after 380 nm");
}
lightSourceData = lightSource.SpectralPowerDistribution.WaveData.GetRange(startIndex, count).ToArray();
materialData = material.ReflectanceDistribution.WaveData.GetRange(startIndex, count).ToArray();
observerXData = observer.ResponseSpectra[0].WaveData.GetRange(startIndex, count).ToArray();
observerYData = observer.ResponseSpectra[1].WaveData.GetRange(startIndex, count).ToArray();
observerZData = observer.ResponseSpectra[2].WaveData.GetRange(startIndex, count).ToArray();
}
else
{
lightSourceData = lightSource.SpectralPowerDistribution.WaveData.ToArray();
materialData = material.ReflectanceDistribution.WaveData.ToArray();
observerXData = observer.ResponseSpectra[0].WaveData.ToArray();
observerYData = observer.ResponseSpectra[1].WaveData.ToArray();
observerZData = observer.ResponseSpectra[2].WaveData.ToArray();
}
// Calculate the L*M product array. This reduces the repeated multiplication operations that would otherwise be
// required.
//
float[] lmProductArray = Utilities.ComputeLMProductArray(lightSourceData, materialData);
Vector3 tristimulusValues = new Vector3();
// Calculate X
//
summation = Utilities.ComputeSummationTerm(lmProductArray, observerXData);
tristimulusValues.X = K * summation * (float)stepSize;
// Calculate Y
//
summation = Utilities.ComputeSummationTerm(lmProductArray, observerYData);
tristimulusValues.Y = K * summation * (float)stepSize;
// Calculate Z
//
summation = Utilities.ComputeSummationTerm(lmProductArray, observerZData);
tristimulusValues.Z = K * summation * (float)stepSize;
return tristimulusValues;
}
/// <summary>
/// Calculates the Tristimulus normalizing constant using the formula
/// K = 100.0 / (total * stepSize)
/// Where total is the sum of products of lightsource power and observers Y channel response
/// </summary>
/// <param name="lightSource">Light source</param>
/// <param name="observer">The observer</param>
/// <returns>The calculated tristimulus constant</returns>
public static float TristimulusNormalizingConstant(LightSource lightSource, Observer observer)
{
int stepSize = lightSource.SpectralPowerDistribution.StepSize;
int start = lightSource.SpectralPowerDistribution.LowestWavelength;
int end = lightSource.SpectralPowerDistribution.HighestWavelength;
int i, index;
float[] observerYData = observer.ResponseSpectra[1].WaveData.ToArray();
float[] lightSourceData = lightSource.SpectralPowerDistribution.WaveData.ToArray();
float total = (float)0.0;
for (i=start, index=0; i <= end; i += stepSize, index++)
{
total += lightSourceData[index] * observerYData[index];
}
return (float)100.0 / (total * (float)stepSize);
}
public static Vector4 GetEquivalentRGB(LightSource lightSource)
{
Vector3 lightXYZ = Utilities.CalculateTristimulusValues(
lightSource,
TheDataManager.GetMaterialByPartialName("White"),
TheDataManager.GetObserverByPartialName("1964"),
true);
return Utilities.CalculateRGBfromXYZ(lightXYZ);
}
