init dump

Sources/JolkEngine/Colour.swift

@@ -0,0 +1,95 @@
+import SDL2
+import HSLuv
+
+
+public struct Colour: Equatable { let r, g, b, a: Float }
+
+public extension Colour
+{
+	static var zero: Self  { .init(r: 0, g: 0, b: 0, a: 0) }
+	static var black: Self { .init(r: 0, g: 0, b: 0, a: 1) }
+	static var white: Self { .init(r: 1, g: 1, b: 1, a: 1) }
+
+	init(r: Float, g: Float, b: Float)
+	{
+		self.init(r: r, g: g, b: b, a: 1.0)
+	}
+
+	init(fromSdl: SDL_Color)
+	{
+		self.init(
+			r: Float(fromSdl.r) / 0xFF,
+			g: Float(fromSdl.g) / 0xFF,
+			b: Float(fromSdl.b) / 0xFF,
+			a: Float(fromSdl.a) / 0xFF)
+	}
+
+	init(fromRgb24: UInt32)
+	{
+		self.init(
+			r: Float((fromRgb24 >> 16) & 0xFF) / 0xFF,
+			g: Float((fromRgb24 >>  8) & 0xFF) / 0xFF,
+			b: Float((fromRgb24 >>  0) & 0xFF) / 0xFF,
+			a: 1)
+	}
+
+	init(fromRgba32: UInt32)
+	{
+		self.init(
+			r: Float((fromRgba32 >> 24) & 0xFF) / 0xFF,
+			g: Float((fromRgba32 >> 16) & 0xFF) / 0xFF,
+			b: Float((fromRgba32 >>  8) & 0xFF) / 0xFF,
+			a: Float((fromRgba32 >>  0) & 0xFF) / 0xFF)
+	}
+
+	func mix(with rhs: Colour, _ amount: Float) -> Colour
+	{
+		let x = amount.saturate
+		return Colour(
+			r: Float.lerp(r, rhs.r, x),
+			g: Float.lerp(g, rhs.g, x),
+			b: Float.lerp(b, rhs.b, x),
+			a: Float.lerp(a, rhs.a, x))
+	}
+
+	func lighten(by: Double) -> Colour
+	{
+		var hue = CGFloat(), sat = CGFloat(), light = CGFloat()
+		rgbToHsluv(CGFloat(r), CGFloat(g), CGFloat(b), &hue, &sat, &light)
+		let gamma: CGFloat = 3.0
+		light = pow((pow(light / 100, 1 / gamma) + CGFloat(by) * 0.8).saturate, gamma) * 100
+		var newR = CGFloat(), newG = CGFloat(), newB = CGFloat()
+		hsluvToRgb(hue, sat, light, &newR, &newG, &newB)
+		return Colour(r: Float(newR), g: Float(newG), b: Float(newB), a: a)
+	}
+
+	var linear: Colour { get
+	{
+		Colour(
+			r: linearFromSrgb(r),
+			g: linearFromSrgb(g),
+			b: linearFromSrgb(b),
+			a: a)
+	} }
+
+	func setAlpha(_ newAlpha: Float) -> Colour
+	{
+		return Colour(r: r, g: g, b: b, a: newAlpha)
+	}
+}
+
+
+@inline(__always) fileprivate func srgbFromLinear(_ x: Float) -> Float
+{
+	return (x < 0.0031308)
+		? x * 12.92
+		: 1.055 * pow(x, 1.0 / 2.4) - 0.055
+}
+
+@inline(__always) fileprivate func linearFromSrgb(_ x: Float) -> Float
+{
+	return (x < 0.04045)
+		? x / 12.92
+		: pow((x + 0.055) / 1.055, 2.4)
+}
+