source/bloom.cpp

   1 /* $Id$
   2
   3 This file is part of libmspgl
   4 Copyright © 2009  Mikko Rasa, Mikkosoft Productions
   5 Distributed under the LGPL
   6 */
   7
   8 #include <cmath>
   9 #include <msp/strings/formatter.h>
  10 #include "bloom.h"
  11 #include "meshbuilder.h"
  12 #include "texunit.h"
  13
  14 using namespace std;
  15
  16 namespace {
  17
  18 static const char blur_vs[]=
  19         "varying vec2 texcoord;\n"
  20         "void main()\n"
  21         "{\n"
  22         "       gl_Position=vec4(gl_Vertex.xy*2.0-1.0, 0.0, 1.0);\n"
  23         "       texcoord=gl_Vertex.xy;\n"
  24         "}";
  25
  26 static const char blur_fs[]=
  27         "uniform sampler2D source;\n"
  28         "uniform vec2 delta;\n"
  29         "uniform float factors[19];\n"
  30         "uniform int size;\n"
  31         "varying vec2 texcoord;\n"
  32         "void main()\n"
  33         "{\n"
  34         "       gl_FragColor=vec4(0.0, 0.0, 0.0, 0.0);\n"
  35         "       for(int i=-size; i<=size; ++i)\n"
  36         "               gl_FragColor+=texture2D(source, texcoord+delta*i)*factors[i+size];\n"
  37         "}";
  38
  39 static const char combine_vs[]=
  40         "varying vec2 texcoord;\n"
  41         "void main()\n"
  42         "{\n"
  43         "       gl_Position=vec4(gl_Vertex.xy*2.0-1.0, 0.0, 1.0);\n"
  44         "       texcoord=gl_Vertex.xy;\n"
  45         "}";
  46
  47 static const char combine_fs[]=
  48         "uniform sampler2D source;\n"
  49         "uniform sampler2D blurred;\n"
  50         "uniform float strength;\n"
  51         "varying vec2 texcoord;\n"
  52         "void main()\n"
  53         "{\n"
  54         "       gl_FragColor=mix(texture2D(source, texcoord), texture2D(blurred, texcoord), strength);\n"
  55         "}";
  56
  57 }
  58
  59 namespace Msp {
  60 namespace GL {
  61
  62 Bloom::Bloom(unsigned w, unsigned h):
  63         blur_shader(blur_vs, blur_fs),
  64         combine_shader(combine_vs, combine_fs),
  65         quad(VERTEX2)
  66 {
  67         int loc=blur_shader.get_uniform_location("delta");
  68         blur_shdata[0].uniform(loc, 1.0f/w, 0.0f);
  69         blur_shdata[1].uniform(loc, 0.0f, 1.0f/h);
  70
  71         loc=blur_shader.get_uniform_location("source");
  72         for(unsigned i=0; i<2; ++i)
  73         {
  74                 blur_shdata[i].uniform(loc, 0);
  75                 tex[i].storage(RGB16F, w, h, 0);
  76                 tex[i].image(0, RGB, UNSIGNED_BYTE, 0);
  77                 tex[i].set_min_filter(NEAREST);
  78         }
  79
  80         combine_shdata.uniform(combine_shader.get_uniform_location("source"), 1);
  81         combine_shdata.uniform(combine_shader.get_uniform_location("blurred"), 0);
  82
  83         set_radius(2.0f);
  84         set_strength(0.2f);
  85
  86         MeshBuilder mbld(quad);
  87         mbld.begin(QUADS);
  88         mbld.vertex(0, 0);
  89         mbld.vertex(1, 0);
  90         mbld.vertex(1, 1);
  91         mbld.vertex(0, 1);
  92         mbld.end();
  93 }
  94
  95 void Bloom::set_radius(float r)
  96 {
  97         if(r<=0.0f)
  98                 throw InvalidParameterValue("Radius must be positive");
  99
 100         int size=min(static_cast<int>(r*3.0f), 9);
 101         int loc=blur_shader.get_uniform_location("size");
 102         blur_shdata[0].uniform(loc, size);
 103         blur_shdata[1].uniform(loc, size);
 104
 105         vector<float> factors(size*2+1);
 106         float sum=0.0f;
 107         r=2*r*r;
 108         for(int i=-size; i<=size; ++i)
 109                 sum+=(factors[size+i]=exp(-i*i/r));
 110
 111         for(int i=0; i<=size*2; ++i)
 112         {
 113                 loc=blur_shader.get_uniform_location(format("factors[%d]", i));
 114                 float f=factors[i]/sum;
 115                 blur_shdata[0].uniform(loc, f);
 116                 blur_shdata[1].uniform(loc, f);
 117         }
 118 }
 119
 120 void Bloom::set_strength(float s)
 121 {
 122         if(s<0.0f || s>1.0f)
 123                 throw InvalidParameterValue("Strength must be in the range [0.0, 1.0]");
 124         combine_shdata.uniform(combine_shader.get_uniform_location("strength"), s);
 125 }
 126
 127 void Bloom::render(const Texture2D &src)
 128 {
 129         const Framebuffer *dest=Framebuffer::current();
 130         blur_shader.bind();
 131         fbo.bind();
 132         src.bind_to(0);
 133         for(unsigned i=0; i<2; ++i)
 134         {
 135                 fbo.attach(COLOR_ATTACHMENT0, tex[i], 0);
 136                 blur_shdata[i].apply();
 137                 quad.draw();
 138                 tex[i].bind_to(0);
 139         }
 140
 141         if(dest)
 142                 dest->bind();
 143         else
 144                 Framebuffer::unbind();
 145
 146         combine_shader.bind();
 147         combine_shdata.apply();
 148         src.bind_to(1);
 149         quad.draw();
 150         Program::unbind();
 151         Texture::unbind();
 152         TexUnit::activate(0);
 153         Texture::unbind();
 154 }
 155
 156 } // namespace GL
 157 } // namespace Msp