source/colorcurve.cpp

   1 #include "colorcurve.h"
   2 #include "mesh.h"
   3 #include "shader.h"
   4 #include "texture2d.h"
   5
   6 using namespace std;
   7
   8 namespace {
   9
  10 static const char fragment_src[] =
  11         "uniform sampler2D texture;\n"
  12         "uniform float peak;\n"
  13         "uniform float brightness;\n"
  14         "varying vec2 texcoord;\n"
  15         "void main()\n"
  16         "{\n"
  17         "       vec4 sample = texture2D(texture, texcoord);\n"
  18         "       float maxc = max(sample.r, max(sample.g, sample.b));\n"
  19         "       if(maxc>1.0-peak)\n"
  20         "       {\n"
  21         "               vec3 saturated = sample.rgb/maxc;\n"
  22         "               if(maxc>1.0+peak)\n"
  23         "               {\n"
  24         "                       gl_FragColor.rgb = mix(vec3(1.0), saturated, 1.0/pow(brightness, maxc-1.0-peak));\n"
  25         "               }\n"
  26         "               else\n"
  27         "               {\n"
  28         "                       float x = (1.0+peak-maxc)/(2.0*peak);\n"
  29         "                       gl_FragColor.rgb = saturated.rgb*(1.0-peak+(1.0-x*x)*peak);\n"
  30         "               }\n"
  31         "               gl_FragColor.a = sample.a;\n"
  32         "       }\n"
  33         "       else\n"
  34         "               gl_FragColor = sample;\n"
  35         "}";
  36
  37 }
  38
  39 namespace Msp {
  40 namespace GL {
  41
  42 ColorCurve::ColorCurve():
  43         quad(get_fullscreen_quad())
  44 {
  45         shprog.attach_shader(get_fullscreen_vertex_shader());
  46         shprog.attach_shader_owned(new FragmentShader(fragment_src));
  47         shprog.link();
  48
  49         set_peak(0.2);
  50         set_brightness(1.5);
  51 }
  52
  53 void ColorCurve::set_peak(float p)
  54 {
  55         if(p<0 || p>1)
  56                 throw invalid_argument("ColorCurve::set_peak");
  57         shdata.uniform("peak", p);
  58 }
  59
  60 void ColorCurve::set_brightness(float b)
  61 {
  62         if(b<1)
  63                 throw invalid_argument("ColorCurve::set_brightness");
  64         shdata.uniform("brightness", b);
  65 }
  66
  67 void ColorCurve::render(const Texture2D &color_buf, const Texture2D &)
  68 {
  69         Bind _bind_shader(shprog);
  70         shdata.apply();
  71         Bind _bind_tex(color_buf);
  72         quad.draw();
  73 }
  74
  75 } // namespace GL
  76 } // namespace Msp