source/core/blend.h

   1 #ifndef MSP_GL_BLEND_H_
   2 #define MSP_GL_BLEND_H_
   3
   4 #include <msp/datafile/objectloader.h>
   5 #include <msp/strings/lexicalcast.h>
   6 #include "color.h"
   7
   8 namespace Msp {
   9 namespace GL {
  10
  11 enum BlendEquation: std::uint8_t
  12 {
  13         ADD,
  14         SUBTRACT,
  15         REVERSE_SUBTRACT,
  16         MIN,
  17         MAX
  18 };
  19
  20 enum BlendFactor: std::uint8_t
  21 {
  22         ZERO,
  23         ONE,
  24         SRC_COLOR,
  25         ONE_MINUS_SRC_COLOR,
  26         SRC_ALPHA,
  27         ONE_MINUS_SRC_ALPHA,
  28         DST_COLOR,
  29         ONE_MINUS_DST_COLOR,
  30         DST_ALPHA,
  31         ONE_MINUS_DST_ALPHA,
  32         CONSTANT_COLOR,
  33         ONE_MINUS_CONSTANT_COLOR,
  34         CONSTANT_ALPHA,
  35         ONE_MINUS_CONSTANT_ALPHA
  36 };
  37
  38 enum ColorWriteMask: std::uint8_t
  39 {
  40         WRITE_NONE = 0,
  41         WRITE_RED = 1,
  42         WRITE_GREEN = 2,
  43         WRITE_BLUE = 4,
  44         WRITE_ALPHA = 8,
  45         WRITE_ALL = 15
  46 };
  47
  48 /**
  49 Blends incoming fragment color values with those already in the framebuffer.
  50 */
  51 struct Blend
  52 {
  53         class Loader: public DataFile::ObjectLoader<Blend>
  54         {
  55         public:
  56                 Loader(Blend &);
  57
  58         private:
  59                 void constant(float, float, float, float);
  60                 void equation(BlendEquation);
  61                 void factors(BlendFactor, BlendFactor);
  62         };
  63
  64         bool enabled = false;
  65         BlendEquation equation = ADD;
  66         BlendFactor src_factor = ONE;
  67         BlendFactor dst_factor = ZERO;
  68         Color constant = { 0.0f, 0.0f, 0.0f, 0.0f };
  69         ColorWriteMask write_mask = WRITE_ALL;
  70         bool alpha_to_coverage = false;
  71
  72         Blend() = default;
  73         Blend(BlendFactor, BlendFactor);
  74         Blend(BlendEquation, BlendFactor, BlendFactor);
  75
  76         bool operator==(const Blend &) const;
  77         bool operator!=(const Blend &b) const { return !operator==(b); }
  78 };
  79
  80 inline bool Blend::operator==(const Blend &other) const
  81 {
  82         return enabled==other.enabled && equation==other.equation && src_factor==other.src_factor &&
  83                 dst_factor==other.dst_factor && constant==other.constant && write_mask==other.write_mask &&
  84                 alpha_to_coverage==other.alpha_to_coverage;
  85 }
  86
  87
  88 inline ColorWriteMask operator|(ColorWriteMask m1, ColorWriteMask m2)
  89 { return static_cast<ColorWriteMask>(static_cast<int>(m1)|static_cast<int>(m2)); }
  90
  91 void operator>>(const LexicalConverter &, BlendEquation &);
  92 void operator<<(LexicalConverter &, BlendEquation);
  93
  94 void operator>>(const LexicalConverter &, BlendFactor &);
  95 void operator<<(LexicalConverter &, BlendFactor);
  96
  97 void operator>>(const LexicalConverter &, ColorWriteMask &);
  98 void operator<<(LexicalConverter &, ColorWriteMask);
  99
 100 } // namespace GL
 101 } // namespace Msp
 102
 103 #include "blend_backend.h"
 104
 105 #endif