source/bloom.cpp

   1 /* $Id$
   2
   3 This file is part of libmspgl
   4 Copyright © 2009-2011  Mikko Rasa, Mikkosoft Productions
   5 Distributed under the LGPL
   6 */
   7
   8 #include <cmath>
   9 #include <msp/strings/formatter.h>
  10 #include "blend.h"
  11 #include "bloom.h"
  12 #include "meshbuilder.h"
  13 #include "misc.h"
  14 #include "tests.h"
  15 #include "texunit.h"
  16
  17 using namespace std;
  18
  19 namespace {
  20
  21 static const char blur_vs[]=
  22         "varying vec2 texcoord;\n"
  23         "void main()\n"
  24         "{\n"
  25         "       gl_Position = vec4(gl_Vertex.xy*2.0-1.0, 0.0, 1.0);\n"
  26         "       texcoord = gl_Vertex.xy;\n"
  27         "}";
  28
  29 static const char blur_fs[]=
  30         "uniform sampler2D source;\n"
  31         "uniform vec2 delta;\n"
  32         "uniform float factors[19];\n"
  33         "uniform int size;\n"
  34         "varying vec2 texcoord;\n"
  35         "void main()\n"
  36         "{\n"
  37         "       gl_FragColor = vec4(0.0, 0.0, 0.0, 0.0);\n"
  38         "       for(int i=0; i<=size*2; ++i)\n"
  39         "               gl_FragColor += texture2D(source, texcoord+delta*float(i-size))*factors[i];\n"
  40         "}";
  41
  42 static const char combine_vs[]=
  43         "varying vec2 texcoord;\n"
  44         "void main()\n"
  45         "{\n"
  46         "       gl_Position = vec4(gl_Vertex.xy*2.0-1.0, 0.0, 1.0);\n"
  47         "       texcoord = gl_Vertex.xy;\n"
  48         "}";
  49
  50 static const char combine_fs[]=
  51         "uniform sampler2D source;\n"
  52         "uniform sampler2D blurred;\n"
  53         "uniform float strength;\n"
  54         "varying vec2 texcoord;\n"
  55         "void main()\n"
  56         "{\n"
  57         "       gl_FragColor = mix(texture2D(source, texcoord), texture2D(blurred, texcoord), strength);\n"
  58         "}";
  59
  60 }
  61
  62 namespace Msp {
  63 namespace GL {
  64
  65 Bloom::Bloom(unsigned w, unsigned h):
  66         blur_shader(blur_vs, blur_fs),
  67         blur_shdata_common(blur_shader),
  68         blur_shdata_x(blur_shader),
  69         blur_shdata_y(blur_shader),
  70         combine_shader(combine_vs, combine_fs),
  71         combine_shdata(combine_shader),
  72         quad(VERTEX2)
  73 {
  74         int loc = blur_shader.get_uniform_location("delta");
  75         blur_shdata_x.uniform(loc, 1.0f/w, 0.0f);
  76         blur_shdata_y.uniform(loc, 0.0f, 1.0f/h);
  77
  78         blur_shdata_common.uniform("source", 0);
  79         for(unsigned i=0; i<2; ++i)
  80         {
  81                 tex[i].set_min_filter(NEAREST);
  82                 tex[i].storage(RGB16F, w, h);
  83         }
  84
  85         combine_shdata.uniform("source", 1);
  86         combine_shdata.uniform("blurred", 0);
  87
  88         combine_texturing.attach(0, tex[1]);
  89
  90         set_radius(2.0f);
  91         set_strength(0.2f);
  92
  93         MeshBuilder mbld(quad);
  94         mbld.begin(TRIANGLE_STRIP);
  95         mbld.vertex(0, 1);
  96         mbld.vertex(0, 0);
  97         mbld.vertex(1, 1);
  98         mbld.vertex(1, 0);
  99         mbld.end();
 100 }
 101
 102 void Bloom::set_radius(float r)
 103 {
 104         if(r<=0.0f)
 105                 throw InvalidParameterValue("Radius must be positive");
 106
 107         int size = min(static_cast<int>(r*3.0f), 9);
 108         blur_shdata_common.uniform("size", size);
 109
 110         vector<float> factors(size*2+1);
 111         float sum = 0.0f;
 112         r = 2*r*r;
 113         for(int i=-size; i<=size; ++i)
 114                 sum += (factors[size+i] = exp(-i*i/r));
 115
 116         for(int i=0; i<=size*2; ++i)
 117                 blur_shdata_common.uniform(format("factors[%d]", i), factors[i]/sum);
 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("strength", s);
 125 }
 126
 127 void Bloom::render(const Texture2D &src, const Texture2D &)
 128 {
 129         Bind unbind_dtest(static_cast<DepthTest *>(0), true);
 130         Bind unbind_blend(static_cast<Blend *>(0), true);
 131
 132         {
 133                 Bind bind_shader(blur_shader);
 134                 blur_shdata_common.apply();
 135                 Bind bind_fbo(fbo, true);
 136                 for(unsigned i=0; i<2; ++i)
 137                 {
 138                         Bind bind_tex(i ? tex[0] : src);
 139                         fbo.attach(COLOR_ATTACHMENT0, tex[i], 0);
 140                         (i ? blur_shdata_y : blur_shdata_x).apply();
 141                         quad.draw();
 142                 }
 143         }
 144
 145         combine_texturing.attach(1, src);
 146         Bind bind_texturing(combine_texturing);
 147         Bind bind_shader(combine_shader);
 148         combine_shdata.apply();
 149         quad.draw();
 150 }
 151
 152 } // namespace GL
 153 } // namespace Msp