source/blend.cpp

   1 #include <msp/gl/extensions/ext_blend_minmax.h>
   2 #include <msp/gl/extensions/ext_blend_subtract.h>
   3 #include "blend.h"
   4
   5 namespace Msp {
   6 namespace GL {
   7
   8 Blend::Blend():
   9         eq(ADD),
  10         src_factor(ONE),
  11         dst_factor(ZERO)
  12 { }
  13
  14 Blend::Blend(BlendFactor sf, BlendFactor df):
  15         eq(ADD),
  16         src_factor(sf),
  17         dst_factor(df)
  18 { }
  19
  20 Blend::Blend(BlendEquation e, BlendFactor sf, BlendFactor df):
  21         eq(e),
  22         src_factor(sf),
  23         dst_factor(df)
  24 {
  25         if(eq==MIN || eq==MAX)
  26                 static Require _req(EXT_blend_minmax);
  27         else if(eq==SUBTRACT || eq==REVERSE_SUBTRACT)
  28                 static Require _req(EXT_blend_subtract);
  29 }
  30
  31 void Blend::bind() const
  32 {
  33         if(set_current(this))
  34         {
  35                 glEnable(GL_BLEND);
  36                 if(EXT_blend_minmax)
  37                         glBlendEquation(eq);
  38                 glBlendFunc(src_factor, dst_factor);
  39         }
  40 }
  41
  42 void Blend::unbind()
  43 {
  44         if(set_current(0))
  45                 glDisable(GL_BLEND);
  46 }
  47
  48 const Blend &Blend::alpha()
  49 {
  50         static Blend blend(SRC_ALPHA, ONE_MINUS_SRC_ALPHA);
  51         return blend;
  52 }
  53
  54 } // namespace GL
  55 } // namespace Msp