private float MinimizeError(
PaletteGenerator generator,
List <PaletteEntry> ramp,
Range <float> range,
Func <PaletteParameters, float, float> function)
{
const int count = 20;
const int iterations = 3;
List <Tuple <float, float> > errors = null;
int index = -1;
for (int i = 0; i < iterations; i++)
{
errors = Errors(generator, ramp, range, count, function);
float min = errors.Min(x => x.Item2);
index = errors.FindIndex(x => x.Item2 == min);
// Get the indices above and below the minimum value
int step = Math.Max(1, (int)(count * 0.3f) / 2);
int startIndex = Math.Max(0, index - step);
startIndex = Math.Min(count - step * 2, startIndex);
int endIndex = startIndex + step * 2;
range = new Range <float>(errors[startIndex].Item1, errors[endIndex].Item1);
}
return(errors[index].Item1);
}
public GeneratedColorPalette(
PaletteGenerator generator,
PaletteParameters parameters)
{
// Adjust base color up if black level is too close to it
XnaHSL baseColor = AdjustBaseColor(parameters.BaseColor, generator.BlackLevel);
// Tint just a little toward yellow based on yellow light
XnaHSL untintedBaseColor = baseColor;
if (baseColor.Saturation > 0)
{
baseColor = baseColor.LerpHue(60, parameters.YellowLight * 0.075f);
}
XnaHSL highlight, specular;
GetHighlight(baseColor, generator, parameters,
out highlight, out specular);
XnaHSL shadow, darkest;
GetShadow(untintedBaseColor, generator, parameters,
out shadow, out darkest);
// Set the calculated values
BaseColor = baseColor;
Darkest = darkest;
Shadow = shadow;
Highlight = highlight;
Specular = specular;
ReducedDepth = parameters.ReducedDepth;
}
private List <Tuple <float, float> > Errors(
PaletteParameters parameters,
List <PaletteEntry> ramp,
Range <float> range,
int count,
Func <PaletteGenerator, float, float> function)
{
PaletteGenerator copyGenerator = (PaletteGenerator)Clone();
PaletteParameters copyParameters = (PaletteParameters)parameters.Clone();
float interval = (range.Maximum - range.Minimum) / count;
var errors = new List <Tuple <float, float> >();
for (int i = 0; i <= count; i++)
{
float value = range.Minimum + interval * i;
function(copyGenerator, value);
// Kind of necessary for user facing values
// Minimize error on blue shadow
copyParameters.MinimizeBlueError(copyGenerator, ramp);
// Minimize error on yellow light
copyParameters.MinimizeYellowError(copyGenerator, ramp);
var palette = copyGenerator.GetPalette(copyParameters);
float error = palette.GetError(ramp);
errors.Add(Tuple.Create(value, error));
}
return(errors);
}
internal void MinimizeBlueError(PaletteGenerator generator, List <PaletteEntry> ramp)
{
var range = BlueRange();
Func <PaletteParameters, float, float> function =
(PaletteParameters parameters, float value) => parameters.BlueShadow = value;
float minimum = MinimizeError(generator, ramp, range, function);
BlueShadow = minimum;
}
internal void MinimizeYellowError(PaletteGenerator generator, List <PaletteEntry> ramp)
{
var range = YellowRange();
Func <PaletteParameters, float, float> function =
(PaletteParameters parameters, float value) => parameters.YellowLight = value;
float minimum = MinimizeError(generator, ramp, range, function);
YellowLight = minimum;
}
internal PaletteRamp(string name, Color darkestColor)
{
Name = name;
_BaseColorIndex = 0;
_Colors = new List <Color>();
_Adjustments = new List <ColorVector>();
Generator = new PaletteGenerator();
BlueYellowAdjustments = true;
SetBlackLevel(darkestColor);
}
public override void CopyFrom(TactileDataContent other)
{
CheckSameClass(other);
var source = (PaletteRamp)other;
Name = source.Name;
_BaseColorIndex = source._BaseColorIndex;
_Colors = new List <Color>(source._Colors);
_Adjustments = new List <ColorVector>(source._Adjustments);
Generator = (PaletteGenerator)source.Generator.Clone();
BlueYellowAdjustments = source.BlueYellowAdjustments;
}
private static void GetHighlight(
XnaHSL baseHSL,
PaletteGenerator generator,
PaletteParameters parameters,
out XnaHSL highlight,
out XnaHSL specular)
{
Color baseSpecular = PaletteGenerator.BaseSpecularColor(baseHSL.GetColor());
// Tint yellow
XnaHSL specularHSL = new XnaHSL(baseSpecular);
// If greyscale, simply treat the hue as yellow
if (float.IsNaN(specularHSL.Hue))
{
specularHSL = specularHSL.SetHue(60);
}
specularHSL = specularHSL.LerpHue(60, parameters.YellowLight);
specularHSL = specularHSL.SetSaturation(MathHelper.Lerp(
specularHSL.Saturation, 1f, parameters.YellowLight));
specularHSL = specularHSL.SetLightness(MathHelper.Lerp(
specularHSL.Lightness, Math.Max(0.5f, specularHSL.Lightness), parameters.YellowLight));
// Add specular
specularHSL = specularHSL.SetLightness(MathHelper.Lerp(
specularHSL.Lightness, 1f, generator.Specularity));
// Reduce the lightness if the base color is darker than the generator color
if (generator.BaseLightness > 0 && baseHSL.Lightness < generator.BaseLightness)
{
float lightnessDiff = generator.BaseLightness - baseHSL.Lightness;
specularHSL = specularHSL.SetLightness(specularHSL.Lightness - (lightnessDiff));
}
float highlightAmount = 0.5f;
// If the base color is sufficiently bright, lighten the specular
// to keep the contrast from getting too low
float lightnessRatio = (baseHSL.Lightness - 0.5f) * 2f;
if (lightnessRatio > 0)
{
specularHSL = specularHSL.SetLightness(
MathHelper.Lerp(specularHSL.Lightness, 1f, lightnessRatio));
highlightAmount = MathHelper.Lerp(0.5f, 1f, lightnessRatio);
}
// Get highlight
XnaHSL highlightHSL = XnaHSL.Lerp(baseHSL, specularHSL, highlightAmount);
highlight = highlightHSL;
specular = specularHSL;
}
private static void GetShadow(
XnaHSL baseHSL,
PaletteGenerator generator,
PaletteParameters parameters,
out XnaHSL shadow,
out XnaHSL darkest)
{
XnaHSL blackHSL = new XnaHSL(
baseHSL.Hue,
baseHSL.Saturation * generator.ShadowAmount,
generator.BlackLevel,
baseHSL.Alpha);
// If the base color is sufficiently bright, lighten the darker shades
float lightnessRatio = (baseHSL.Lightness - 0.5f) * 2f;
if (lightnessRatio > 0)
{
blackHSL = blackHSL.SetSaturation(blackHSL.Saturation * (1f - lightnessRatio * 0.95f));
float blackLuma = Color_Util.GetLuma(blackHSL.GetColor());
// Increase the lightness by more if it's a color with a low
// luma to lightness ratio
float lumaRatio = 1f;
if (blackLuma > 0)
{
lumaRatio = blackHSL.Lightness / blackLuma;
}
blackHSL = blackHSL.SetLightness(
MathHelper.Lerp(blackHSL.Lightness,
MathHelper.Lerp(blackHSL.Lightness, 1f, 0.25f),
lightnessRatio * lumaRatio));
}
// Tint black and shadow blue
blackHSL = blackHSL.LerpHue(240, parameters.BlueShadow);
blackHSL = blackHSL.SetSaturation(MathHelper.Lerp(blackHSL.Saturation, 1f, parameters.BlueShadow / 4f));
XnaHSL shadowHSL = XnaHSL.Lerp(blackHSL, baseHSL, generator.ShadowAmount);
shadowHSL = shadowHSL.SetSaturation(MathHelper.Lerp(blackHSL.Saturation, baseHSL.Saturation, 0.5f));
shadowHSL = shadowHSL.SetHue(blackHSL.Hue);
shadowHSL = shadowHSL.LerpHue(baseHSL.Hue, 0.25f);
shadow = shadowHSL;
darkest = blackHSL;
}
private List <Tuple <float, float> > Errors(
PaletteGenerator generator,
List <PaletteEntry> ramp,
Range <float> range,
int count,
Func <PaletteParameters, float, float> function)
{
PaletteParameters copyParameters = (PaletteParameters)Clone();
float interval = (range.Maximum - range.Minimum) / count;
var errors = new List <Tuple <float, float> >();
for (int i = 0; i <= count; i++)
{
float value = range.Minimum + interval * i;
function(copyParameters, value);
var palette = generator.GetPalette(copyParameters);
float error = palette.GetError(ramp);
errors.Add(Tuple.Create(value, error));
}
return(errors);
}
private PaletteGenerator(PaletteGenerator source)
{
CopyFrom(source);
}