source/colorcurve.cpp

   1 #include <cmath>
   2 #include "color.h"
   3 #include "colorcurve.h"
   4 #include "mesh.h"
   5 #include "shader.h"
   6 #include "texture2d.h"
   7
   8 using namespace std;
   9
  10 namespace {
  11
  12 static const char fragment_src[] =
  13         "uniform sampler2D texture;\n"
  14         "uniform sampler1D curve;\n"
  15         "uniform float peak;\n"
  16         "uniform float brightness;\n"
  17         "varying vec2 texcoord;\n"
  18         "void main()\n"
  19         "{\n"
  20         "       vec4 sample = texture2D(texture, texcoord);\n"
  21         "       float maxc = max(sample.r, max(sample.g, sample.b));\n"
  22         "       if(maxc>1.0-peak)\n"
  23         "       {\n"
  24         "               vec3 saturated = sample.rgb/maxc;\n"
  25         "               if(maxc>1.0+peak)\n"
  26         "               {\n"
  27         "                       sample.rgb = mix(vec3(1.0), saturated, 1.0/pow(brightness, maxc-1.0-peak));\n"
  28         "               }\n"
  29         "               else\n"
  30         "               {\n"
  31         "                       float x = (1.0+peak-maxc)/(2.0*peak);\n"
  32         "                       sample.rgb = saturated.rgb*(1.0-peak+(1.0-x*x)*peak);\n"
  33         "               }\n"
  34         "       }\n"
  35         "       gl_FragColor = vec4(texture1D(curve, sample.r).r, texture1D(curve, sample.g).r, texture1D(curve, sample.b).r, sample.a);\n"
  36         "}";
  37
  38 }
  39
  40 namespace Msp {
  41 namespace GL {
  42
  43 ColorCurve::ColorCurve():
  44         quad(get_fullscreen_quad())
  45 {
  46         shprog.attach_shader(get_fullscreen_vertex_shader());
  47         shprog.attach_shader_owned(new FragmentShader(fragment_src));
  48         shprog.link();
  49
  50         shdata.uniform("texture", 0);
  51         shdata.uniform("curve", 1);
  52
  53         curve.storage(LUMINANCE, 256);
  54         curve.set_min_filter(LINEAR);
  55         curve.set_wrap(CLAMP_TO_EDGE);
  56
  57         set_peak(0.2);
  58         set_brightness(1.5);
  59         set_linear();
  60 }
  61
  62 void ColorCurve::set_peak(float p)
  63 {
  64         if(p<0 || p>1)
  65                 throw invalid_argument("ColorCurve::set_peak");
  66         shdata.uniform("peak", p);
  67 }
  68
  69 void ColorCurve::set_brightness(float b)
  70 {
  71         if(b<1)
  72                 throw invalid_argument("ColorCurve::set_brightness");
  73         shdata.uniform("brightness", b);
  74 }
  75
  76 void ColorCurve::set_gamma(float g)
  77 {
  78         if(g<0.1 || g>10)
  79                 throw invalid_argument("ColorCurve::set_gamma");
  80
  81         unsigned char curve_data[256];
  82         for(unsigned i=0; i<256; ++i)
  83                 curve_data[i] = pow(i/255.0f, 1/g)*255+0.5f;
  84         curve.image(0, LUMINANCE, UNSIGNED_BYTE, curve_data);
  85 }
  86
  87 void ColorCurve::set_srgb()
  88 {
  89         unsigned char curve_data[256];
  90         curve_data[0] = 0;
  91         for(unsigned i=1; i<256; ++i)
  92                 curve_data[i] = to_srgb(i/255.0f)*255+0.5f;
  93         curve.image(0, LUMINANCE, UNSIGNED_BYTE, curve_data);
  94 }
  95
  96 void ColorCurve::set_linear()
  97 {
  98         unsigned char curve_data[256];
  99         for(unsigned i=0; i<256; ++i)
 100                 curve_data[i] = i;
 101         curve.image(0, LUMINANCE, UNSIGNED_BYTE, curve_data);
 102 }
 103
 104 void ColorCurve::render(const Texture2D &color_buf, const Texture2D &)
 105 {
 106         Bind _bind_shader(shprog);
 107         shdata.apply();
 108         Bind _bind_tex(color_buf);
 109         Bind _bind_curve(curve, 1);
 110         quad.draw();
 111 }
 112
 113 } // namespace GL
 114 } // namespace Msp