Namespace ActiveBasic
Namespace OpenGL

	'色情報を扱うためのインターフェース
	Class GLColor
	Public /* property */
		Abstract Function A() As Single
		Abstract Function B() As Single
		Abstract Function G() As Single
		Abstract Function R() As Single
		Abstract Function GetPtr() As *Single

	Public /* method */
		Function Equals(c As GLColor) As Boolean
			If (This.R = c.R) and (This.G = c.G) and (This.B = c.B) and (This.A = c.A) Then
				Return True
			Else
				Return False
			End If
		End Function
	Function GetBrightness() As Single
		Return Detail.RGBToBrightness(This.R,This.G,This.B)
	End Function
	Function GetHue() As Single
		Return Detail.RGBToHue(This.R,This.G,This.B)
	End Function
	Function GetSaturation() As Single
		Return Detail.RGBToSaturation(This.R,This.G,This.B)
	End Function

	Public /* operator */
		Function Operator == (c As GLColor) As Boolean
			Return Equals(c)
		End Function
		Function Operator <> (c As GLColor) As Boolean
			Return Not Equals(c)
		End Function
	End Class

	Class Color3
		Inherits GLColor
	Public /* constractor */
		Sub Color3()
			color[0]=0.0
			color[1]=0.0
			color[2]=0.0
			color[3]=1.0
		End Sub
		Sub Color3(red As Single, green As Single, blue As Single)
			color[0]=red
			color[1]=green
			color[2]=blue
			color[3]=1.0
		End Sub
		Sub Color3(c As System.Drawing.Color)
			color[0]=c.R
			color[1]=c.G
			color[2]=c.B
			color[3]=1.0
		End Sub
		Sub Color3(c As Color4)
			color[0]=c.R
			color[1]=c.G
			color[2]=c.B
			color[3]=1.0
		End Sub

	Public /* property */
		Override Function A() As Single
			Return color[3]
		End Function
		Sub B(blue As Single)
			color[2]=blue
		End Sub
		Override Function B() As Single
			Return color[2]
		End Function
		Sub G(green As Single)
			color[1]=green
		End Sub
		Function G() As Single
			Return color[1]
		End Function
		Sub R(red As Single)
			color[0]=red
		End Sub
		Override Function R() As Single
			Return color[0]
		End Function

	Public /* operator */
		Function Operator () As Color4
			Return New Color4(This,1.0)
		End Function

	Public /* method */
		Override Function GetPtr() As *Single
			Return color
		End Function

	Public /* static method */
		Static Function FromCOLORREF(c As COLORREF) As GLColor
			Dim r As Byte, g As Byte, b As Byte
			r = c As Byte
			g = (c>>8) As Byte
			b = (c>>16) As Byte
			Return New Color3(r/255.0,g/255.0,b/255.0)
		End Function
		Static Function FromHSB(hue As Single, saturation As Single, brightness As Single) As Color3
			Return Detail.HSBToColor3(hue,saturation,brightness)
		End Function
		Static Function FromHLS(hue As Single, lightness As Single, saturation As Single) As Color3
			Return Detail.HLSToColor3(hue, lightness, saturation)
		End Function

	Protected
		color[3] As Single
	End Class

	Class Color4
		Inherits GLColor

	Public /* constractor */
		Sub Color4()
			color[0]=0.0
			color[1]=0.0
			color[2]=0.0
			color[3]=1.0
		End Sub
		Sub Color4(red As Single, green As Single, blue As Single, alpha As Single)
			color[0]=red
			color[1]=green
			color[2]=blue
			color[3]=alpha
		End Sub
		Sub Color4(c As System.Drawing.Color)
			color[0]=c.R
			color[1]=c.G
			color[2]=c.B
			color[3]=c.A
		End Sub
		Sub Color4(c As Color3, alpha As Single)
			color[0]=c.R
			color[1]=c.G
			color[2]=c.B
			color[3]=alpha
		End Sub

	Public /* property */
		Sub A(alpha As Single)
			color[3]=alpha
		End Sub
		Override Function A() As Single
			Return color[3]
		End Function
		Sub B(blue As Single)
			color[2]=blue
		End Sub
		Override Function B() As Single
			Return color[2]
		End Function
		Sub G(green As Single)
			color[1]=green
		End Sub
		Function G() As Single
			Return color[1]
		End Function
		Sub R(red As Single)
			color[0]=red
		End Sub
		Override Function R() As Single
			Return color[0]
		End Function

		Function Operator () As Color3
			Return New Color3(This)
		End Function

	Public /* method */
		Override Function GetPtr() As *Single
			Return color
		End Function

	Public /* static method */
		Static Function FromCOLORREF(c As COLORREF) As Color4
			Dim r As Byte, g As Byte, b As Byte
			r = c As Byte
			g = (c>>8) As Byte
			b = (c>>16) As Byte
			Return New Color4(r/255.0,g/255.0,b/255.0,1.0)
		End Function
		Static Function FromHSB(hue As Single, saturation As Single, brightness As Single) As Color4
			Return Detail.HSBToColor3(hue,saturation,brightness)
		End Function
		Static Function FromHLS(hue As Single, lightness As Single, saturation As Single) As Color4
			Return Detail.HLSToColor3(hue, lightness, saturation)
		End Function

	Protected
		color[3] As Single
	End Class

	Namespace Detail
		Function HSBToColor3(hue As Single, saturation As Single, brightness As Single) As Color3
			'cramping
			If hue >= 360.0 Then hue = 0.0
			If hue < 0.0 Then hue = 0.0
			If saturation > 1.0 Then saturation = 1.0
			If saturation < 0.0 Then saturation = 0.0
			If brightness > 1.0 Then brightness = 1.0
			If brightness < 0.0 Then brightness = 0.0

			'grayscale
			If saturation = 0.0 Then
				Return New Color3(brightness,brightness,brightness)
			End If

			Dim i = Int(hue/60.0) As Long
			Dim f = hue/60.0 - i As Single
			Dim v = brightness As Single
			Dim m = brightness * (1.0 - saturation) As Single
			Dim n = brightness * (1.0 - saturation*f) As Single
			Dim k = brightness * (1.0 - saturation*(1.0 - f)) As Single

			Dim r As Single, g As Single, b As Single

			Select Case i
				Case 0
					r = v
					g = k
					b = m
				Case 1
					r = n
					g = v
					b = m
				Case 2
					r = m
					g = v
					b = k
				Case 3
					r = m
					g = n
					b = v
				Case 4
					r = k
					g = m
					b = v
				Case 5
					r = v
					g = m
					b = n
			End Select
			Return New Color3(r,g,b)
		End Function

		Function HLSToColor3(hue As Single, lightness As Single, saturation As Single) As Color3
			'cramping
			If hue >= 360.0 Then hue = 0.0
			If hue < 0.0 Then hue = 0.0
			If lightness > 1.0 Then lightness = 1.0
			If lightness < 0.0 Then lightness = 0.0
			If saturation > 1.0 Then saturation = 1.0
			If saturation < 0.0 Then saturation = 0.0

			'max - min
			Dim max As Single
			Dim min As Single
			If lightness =< 0.5 Then
				min = lightness * (1.0 - saturation)
				max = 2*lightness - min
			Else
				max = lightness * (1.0 - saturation) + saturation
				min = 2*lightness - max
			End If

			'grayscale
			If saturation = 0.0 Then
				Return New Color3(lightness,lightness,lightness)
			End If

			Dim r As Single, g As Single, b As Single

			'red
			Dim h = hue + 120.0 As Single
			If h > 360.0 Then h -= 360.0
			If h < 60.0 Then
				r = min + (max - min)*h/60.0
			ElseIf (h => 60.0) and (h < 180.0) Then
				r = max
			ElseIf (h => 180.0) and (h < 240.0) Then
				r = min + (max - min)*(240.0-h)/60.0
			ElseIf h => 240.0 Then
				r = min
			End If

			'green
			h = hue
			If h < 60.0 Then
				g = min + (max - min)*h/60.0
			ElseIf (h => 60.0) and (h < 180.0) Then
				g = max
			ElseIf (h => 180.0) and (h < 240.0) Then
				g = min + (max - min)*(240.0-h)/60.0
			ElseIf h => 240.0 Then
				g = min
			End If


			'blue
			h = hue - 120.0 As Single
			If h < 0.0 Then h += 360.0

			If h < 60.0 Then
				b = min + (max - min)*h/60.0
			ElseIf (h => 60.0) and (h < 180.0) Then
				b = max
			ElseIf (h => 180.0) and (h < 240.0) Then
				b = min + (max - min)*(240.0-h)/60.0
			ElseIf h => 240.0 Then
				b = min
			End If

			Return New Color3(r,g,b)
		End Function

		Function RGBToHue(red As Single, green As Single, blue As Single) As Single
			Dim max As Single, min As Single, d As Single
			max = System.Math.Max(System.Math.Max(red, green), blue)
			min = System.Math.Min(System.Math.Min(red, green), blue)
			d = max - min
			If green = max Then
				Return ((blue - red) / d * 60.0 + 120.0) As Single
			ElseIf blue = max Then
				Return ((red - green) / d * 60 + 240) As Single
			ElseIf green < blue Then
				Return ((green - blue) / d * 60 + 360) As Single
			Else
				Return ((green - blue) / d * 60) As Single
			EndIf
		End Function

		Function RGBToSaturation(red As Single, green As Single, blue As Single) As Single
			Dim max = System.Math.Max(System.Math.Max(red, green), blue) As Single
			Dim min = System.Math.Min(System.Math.Min(red, green), blue) As Single
			Return (max - min) / max
		End Function

		Function RGBToBrightness(red As Single, green As Single, blue As Single) As Single
			Dim max = System.Math.Max(System.Math.Max(red, green), blue)
			Return max
		End Function
	End Namespace
End Namespace
End Namespace