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;
}