nudsfml.graphics.blendmode source code

1 module nudsfml.graphics.blendmode;
2 
3 struct BlendMode {
4     /**
5      * Enumeration of the blending factors.
6      *
7      * The factors are mapped directly to their OpenGL equivalents,
8      * specified by `glBlendFunc()` or `glBlendFuncSeparate()`.
9      */
10     enum Factor {
11         /// (0, 0, 0, 0)
12         Zero,
13         /// (1, 1, 1, 1)
14         One,
15         /// (src.r, src.g, src.b, src.a)
16         SrcColor,
17         /// (1, 1, 1, 1) - (src.r, src.g, src.b, src.a)
18         OneMinunSrcColor,
19         /// (dst.r, dst.g, dst.b, dst.a)
20         DstColor,
21         /// (1, 1, 1, 1) - (dst.r, dst.g, dst.b, dst.a)
22         OneMinusDstColor,
23         /// (src.a, src.a, src.a, src.a)
24         SrcAlpha,
25         /// (1, 1, 1, 1) - (src.a, src.a, src.a, src.a)
26         OneMinusSrcAlpha,
27         /// (dst.a, dst.a, dst.a, dst.a)
28         DstAlpha,
29         /// (1, 1, 1, 1) - (dst.a, dst.a, dst.a, dst.a)
30         OneMinusDstAlpha
31     }
32 
33     /**
34      * Enumeration of the blending equations
35      *
36      * The equations are mapped directly to their OpenGL equivalents,
37      * specified by glBlendEquation() or glBlendEquationSeparate().
38      */
39     enum Equation {
40         /// Pixel = Src * SrcFactor + Dst * DstFactor
41         Add,
42         /// Pixel = Src * SrcFactor - Dst * DstFactor
43         Subtract,
44         /// Pixel = Dst * DstFactor - Src * SrcFactor
45         ReverseSubtract
46     }
47 
48     /// Blend source and dest according to dest alpha.
49     enum Alpha = BlendMode(Factor.SrcAlpha, Factor.OneMinusSrcAlpha, Equation.Add, Factor.One, Factor.OneMinusSrcAlpha, Equation.Add);
50     /// Add source to dest.
51     enum Add = BlendMode(Factor.SrcAlpha, Factor.One, Equation.Add, Factor.One, Factor.One, Equation.Add);
52     /// Multiply source and dest.
53     enum Multiply = BlendMode(Factor.DstColor, Factor.Zero, Equation.Add, Factor.DstColor, Factor.Zero, Equation.Add);
54     /// Overwrite dest with source.
55     enum None = BlendMode(Factor.One, Factor.Zero, Equation.Add, Factor.One, Factor.Zero, Equation.Add);
56 
57     /// Source blending factor for the color channels.
58     Factor colorSrcFactor = Factor.SrcAlpha;
59     /// Destination blending factor for the color channels.
60     Factor colorDstFactor = Factor.OneMinusSrcAlpha;
61     /// Blending equation for the color channels.
62     Equation colorEquation = Equation.Add;
63     /// Source blending factor for the alpha channel.
64     Factor alphaSrcFactor = Factor.One;
65     /// Destination blending factor for the alpha channel.
66     Factor alphaDstFactor = Factor.OneMinusSrcAlpha;
67     /// Blending equation for the alpha channel.
68     Equation alphaEquation = Equation.Add;
69 
70     /**
71      * Construct the blend mode given the factors and equation.
72      *
73      * This constructor uses the same factors and equation for both
74      * color and alpha components. It also defaults to the Add equation.
75      *
76      * Params:
77      * sourceFactor      = Specifies how to compute the source factor for the
78                            color and alpha channels
79      * destinationFactor = Specifies how to compute the destination factor for
80                            the color and alpha channels
81      * blendEquation     = Specifies how to combine the source and destination
82                            colors and alpha
83      */
84     this(Factor sourceFactor, Factor destinationFactor, Equation blendEquation = Equation.Add) {
85         colorSrcFactor = sourceFactor;
86         colorDstFactor = destinationFactor;
87         colorEquation = blendEquation;
88 
89         alphaSrcFactor = sourceFactor;
90         alphaDstFactor = destinationFactor;
91         alphaEquation = blendEquation;
92     }
93 
94     /**
95      * Construct the blend mode given the factors and equation.
96      *
97      * Params:
98      * colorSourceFactor      = Specifies how to compute the source factor for
99                                 the color channels
100      * colorDestinationFactor = Specifies how to compute the destination factor
101                                 for the color channels
102      * colorBlendEquation     = Specifies how to combine the source and
103                                 destination colors
104      * alphaSourceFactor      = Specifies how to compute the source factor
105      * alphaDestinationFactor = Specifies how to compute the destination factor
106      * alphaBlendEquation     = Specifies how to combine the source and
107                                 destination alphas
108      */
109     this(Factor colorSourceFactor, Factor colorDestinationFactor, Equation colorBlendEquation, Factor alphaSourceFactor, Factor alphaDestinationFactor, Equation alphaBlendEquation) {
110         colorSrcFactor = colorSourceFactor;
111         colorDstFactor = colorDestinationFactor;
112         colorEquation = colorBlendEquation;
113 
114         alphaSrcFactor = alphaSourceFactor;
115         alphaDstFactor = alphaDestinationFactor;
116         alphaEquation = alphaBlendEquation;
117     }
118 
119     bool opEquals(BlendMode rhs) const {
120 		return (colorSrcFactor == rhs.colorSrcFactor &&
121                 colorDstFactor == rhs.colorDstFactor &&
122                 colorEquation == rhs.colorEquation   &&
123                 alphaSrcFactor == rhs.alphaSrcFactor &&
124                 alphaDstFactor == rhs.alphaDstFactor &&
125                 alphaEquation == rhs.alphaEquation );
126 	}
127 }