source/bloom.cpp

   1 #include <cmath>
   2 #include <msp/strings/format.h>
   3 #include "blend.h"
   4 #include "bloom.h"
   5 #include "meshbuilder.h"
   6 #include "misc.h"
   7 #include "tests.h"
   8 #include "texunit.h"
   9
  10 using namespace std;
  11
  12 namespace {
  13
  14 static const char blur_vs[]=
  15         "varying vec2 texcoord;\n"
  16         "void main()\n"
  17         "{\n"
  18         "       gl_Position = vec4(gl_Vertex.xy*2.0-1.0, 0.0, 1.0);\n"
  19         "       texcoord = gl_Vertex.xy;\n"
  20         "}";
  21
  22 static const char blur_fs[]=
  23         "uniform sampler2D source;\n"
  24         "uniform vec2 delta;\n"
  25         "uniform float factors[19];\n"
  26         "uniform int size;\n"
  27         "varying vec2 texcoord;\n"
  28         "void main()\n"
  29         "{\n"
  30         "       gl_FragColor = vec4(0.0, 0.0, 0.0, 0.0);\n"
  31         "       for(int i=0; i<=size*2; ++i)\n"
  32         "               gl_FragColor += texture2D(source, texcoord+delta*float(i-size))*factors[i];\n"
  33         "}";
  34
  35 static const char combine_vs[]=
  36         "varying vec2 texcoord;\n"
  37         "void main()\n"
  38         "{\n"
  39         "       gl_Position = vec4(gl_Vertex.xy*2.0-1.0, 0.0, 1.0);\n"
  40         "       texcoord = gl_Vertex.xy;\n"
  41         "}";
  42
  43 static const char combine_fs[]=
  44         "uniform sampler2D source;\n"
  45         "uniform sampler2D blurred;\n"
  46         "uniform float strength;\n"
  47         "varying vec2 texcoord;\n"
  48         "void main()\n"
  49         "{\n"
  50         "       gl_FragColor = mix(texture2D(source, texcoord), texture2D(blurred, texcoord), strength);\n"
  51         "}";
  52
  53 }
  54
  55 namespace Msp {
  56 namespace GL {
  57
  58 Bloom::Bloom(unsigned w, unsigned h):
  59         blur_shader(blur_vs, blur_fs),
  60         combine_shader(combine_vs, combine_fs),
  61         quad(VERTEX2)
  62 {
  63         blur_shdata[0].uniform("delta", 1.0f/w, 0.0f);
  64         blur_shdata[1].uniform("delta", 0.0f, 1.0f/h);
  65
  66         blur_shdata_common.uniform("source", 0);
  67         for(unsigned i=0; i<2; ++i)
  68         {
  69                 tex[i].set_min_filter(NEAREST);
  70                 tex[i].storage(RGB16F, w, h);
  71         }
  72
  73         combine_shdata.uniform("source", 1);
  74         combine_shdata.uniform("blurred", 0);
  75
  76         combine_texturing.attach(0, tex[1]);
  77
  78         set_radius(2.0f);
  79         set_strength(0.2f);
  80
  81         MeshBuilder mbld(quad);
  82         mbld.begin(TRIANGLE_STRIP);
  83         mbld.vertex(0, 1);
  84         mbld.vertex(0, 0);
  85         mbld.vertex(1, 1);
  86         mbld.vertex(1, 0);
  87         mbld.end();
  88 }
  89
  90 void Bloom::set_radius(float r)
  91 {
  92         if(r<=0.0f)
  93                 throw out_of_range("Bloom::set_radius");
  94
  95         int size = min(static_cast<int>(r*3.0f), 9);
  96         blur_shdata_common.uniform("size", size);
  97
  98         vector<float> factors(size*2+1);
  99         float sum = 0.0f;
 100         r = 2*r*r;
 101         for(int i=-size; i<=size; ++i)
 102                 sum += (factors[size+i] = exp(-i*i/r));
 103
 104         for(int i=0; i<=size*2; ++i)
 105                 blur_shdata_common.uniform(format("factors[%d]", i), factors[i]/sum);
 106 }
 107
 108 void Bloom::set_strength(float s)
 109 {
 110         if(s<0.0f || s>1.0f)
 111                 throw out_of_range("Bloom::set_strength");
 112         combine_shdata.uniform("strength", s);
 113 }
 114
 115 void Bloom::render(const Texture2D &src, const Texture2D &)
 116 {
 117         Bind unbind_dtest(static_cast<DepthTest *>(0), true);
 118         Bind unbind_blend(static_cast<Blend *>(0), true);
 119
 120         {
 121                 Bind bind_shader(blur_shader);
 122                 blur_shdata_common.apply();
 123                 Bind bind_fbo(fbo, true);
 124                 for(unsigned i=0; i<2; ++i)
 125                 {
 126                         Bind bind_tex(i ? tex[0] : src);
 127                         fbo.attach(COLOR_ATTACHMENT0, tex[i], 0);
 128                         blur_shdata[i].apply();
 129                         quad.draw();
 130                 }
 131         }
 132
 133         combine_texturing.attach(1, src);
 134         Bind bind_texturing(combine_texturing);
 135         Bind bind_shader(combine_shader);
 136         combine_shdata.apply();
 137         quad.draw();
 138 }
 139
 140 } // namespace GL
 141 } // namespace Msp