source/colorcurve.cpp

   1 #include <cmath>
   2 #include "colorcurve.h"
   3 #include "mesh.h"
   4 #include "shader.h"
   5 #include "texture2d.h"
   6
   7 using namespace std;
   8
   9 namespace {
  10
  11 static const char fragment_src[] =
  12         "uniform sampler2D texture;\n"
  13         "uniform sampler1D curve;\n"
  14         "uniform float peak;\n"
  15         "uniform float brightness;\n"
  16         "varying vec2 texcoord;\n"
  17         "void main()\n"
  18         "{\n"
  19         "       vec4 sample = texture2D(texture, texcoord);\n"
  20         "       float maxc = max(sample.r, max(sample.g, sample.b));\n"
  21         "       if(maxc>1.0-peak)\n"
  22         "       {\n"
  23         "               vec3 saturated = sample.rgb/maxc;\n"
  24         "               if(maxc>1.0+peak)\n"
  25         "               {\n"
  26         "                       sample.rgb = mix(vec3(1.0), saturated, 1.0/pow(brightness, maxc-1.0-peak));\n"
  27         "               }\n"
  28         "               else\n"
  29         "               {\n"
  30         "                       float x = (1.0+peak-maxc)/(2.0*peak);\n"
  31         "                       sample.rgb = saturated.rgb*(1.0-peak+(1.0-x*x)*peak);\n"
  32         "               }\n"
  33         "       }\n"
  34         "       gl_FragColor = vec4(texture1D(curve, sample.r).r, texture1D(curve, sample.g).r, texture1D(curve, sample.b).r, sample.a);\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         shdata.uniform("texture", 0);
  50         shdata.uniform("curve", 1);
  51
  52         curve.storage(LUMINANCE, 256);
  53         curve.set_min_filter(LINEAR);
  54         curve.set_wrap(CLAMP_TO_EDGE);
  55
  56         set_peak(0.2);
  57         set_brightness(1.5);
  58         set_linear();
  59 }
  60
  61 void ColorCurve::set_peak(float p)
  62 {
  63         if(p<0 || p>1)
  64                 throw invalid_argument("ColorCurve::set_peak");
  65         shdata.uniform("peak", p);
  66 }
  67
  68 void ColorCurve::set_brightness(float b)
  69 {
  70         if(b<1)
  71                 throw invalid_argument("ColorCurve::set_brightness");
  72         shdata.uniform("brightness", b);
  73 }
  74
  75 void ColorCurve::set_gamma(float g)
  76 {
  77         if(g<0.1 || g>10)
  78                 throw invalid_argument("ColorCurve::set_gamma");
  79
  80         unsigned char curve_data[256];
  81         for(unsigned i=0; i<256; ++i)
  82                 curve_data[i] = pow(i/255.0f, 1/g)*255+0.5f;
  83         curve.image(0, LUMINANCE, UNSIGNED_BYTE, curve_data);
  84 }
  85
  86 void ColorCurve::set_srgb()
  87 {
  88         unsigned char curve_data[256];
  89         curve_data[0] = 0;
  90         for(unsigned i=1; i<256; ++i)
  91                 curve_data[i] = (1.055*pow(i/255.0f, 1/2.4f)-0.055)*255+0.5;
  92         curve.image(0, LUMINANCE, UNSIGNED_BYTE, curve_data);
  93 }
  94
  95 void ColorCurve::set_linear()
  96 {
  97         unsigned char curve_data[256];
  98         for(unsigned i=0; i<256; ++i)
  99                 curve_data[i] = i;
 100         curve.image(0, LUMINANCE, UNSIGNED_BYTE, curve_data);
 101 }
 102
 103 void ColorCurve::render(const Texture2D &color_buf, const Texture2D &)
 104 {
 105         Bind _bind_shader(shprog);
 106         shdata.apply();
 107         Bind _bind_tex(color_buf);
 108         Bind _bind_curve(curve, 1);
 109         quad.draw();
 110 }
 111
 112 } // namespace GL
 113 } // namespace Msp