source/ambientocclusion.cpp

   1 /* $Id$
   2
   3 This file is part of libmspgl
   4 Copyright © 2010-2011  Mikko Rasa, Mikkosoft Productions
   5 Distributed under the LGPL
   6 */
   7
   8 #include <cmath>
   9 #include "ambientocclusion.h"
  10 #include "blend.h"
  11 #include "meshbuilder.h"
  12 #include "tests.h"
  13
  14 namespace {
  15
  16 const char vertex_shader[] =
  17         "varying vec2 texcoord;\n"
  18         "void main()\n"
  19         "{\n"
  20         "       gl_Position = gl_Vertex;\n"
  21         "       texcoord = gl_Vertex.xy*0.5+0.5;\n"
  22         "}\n";
  23
  24 const char occlude_fs[] =
  25         "uniform sampler2D depth;\n"
  26         "uniform sampler2D rotate;\n"
  27         "uniform vec2 screen_size;\n"
  28         "uniform vec2 depth_ratio;\n"
  29         "uniform float darkness;\n"
  30         "varying vec2 texcoord;\n"
  31         "void main()\n"
  32         "{\n"
  33         "       mat2 transform = mat2(texture2D(rotate, texcoord*screen_size/4.0)*2.0-1.0)\n"
  34         "               *mat2(screen_size.y/screen_size.x, 0.0, 0.0, 1.0)*3.0/screen_size.y;\n"
  35         "       float sample = depth_ratio.x/(texture2D(depth, texcoord).r-depth_ratio.y);\n"
  36         "       float sum = 0.0;\n"
  37         "       for(int i=0; i<=3; ++i)\n"
  38         "               for(int j=0; j<=3; ++j)\n"
  39         "               {\n"
  40         "                       vec2 offs = transform*vec2(float(i)-1.5, float(j)-1.5);\n"
  41         "                       float dxy = length(offs)*-sample;\n"
  42         "                       float dz = depth_ratio.x/(texture2D(depth, texcoord+offs).r-depth_ratio.y)-sample;\n"
  43         "                       if(abs(dz)<3*dxy)\n"
  44         "                               sum += atan(dz/dxy)/1.570796;\n"
  45         "                       else if(dz<0)\n"
  46         "                               sum -= 0.8;\n"
  47         "               }\n"
  48         "       gl_FragColor = vec4(min(1.0-sum*darkness/16.0, 1.0), 0.0, 0.0, 1.0);\n"
  49         "}\n";
  50
  51 const char combine_fs[] =
  52         "uniform sampler2D color;\n"
  53         "uniform sampler2D depth;\n"
  54         "uniform sampler2D occlusion;\n"
  55         "uniform vec2 screen_size;\n"
  56         "uniform vec2 depth_ratio;\n"
  57         "varying vec2 texcoord;\n"
  58         "void main()\n"
  59         "{\n"
  60         "       float sample = depth_ratio.x/(texture2D(depth, texcoord).r-depth_ratio.y);\n"
  61         "       float sum = 1.0;\n"
  62         "       float count = 1.0;\n"
  63         "       for(int i=0; i<=3; ++i)\n"
  64         "               for(int j=0; j<=3; ++j)\n"
  65         "               {\n"
  66         "                       vec2 offs = vec2(float(i)-1.5, float(j)-1.5)/screen_size;\n"
  67         "                       float dxy = length(offs)*-sample;\n"
  68         "                       float dz = depth_ratio.x/(texture2D(depth, texcoord+offs).r-depth_ratio.y)-sample;\n"
  69         "                       if(abs(dz)<3*dxy)\n"
  70         "                       {\n"
  71         "                               sum += texture2D(occlusion, texcoord+offs).r;\n"
  72         "                               count += 1.0;\n"
  73         "                       }\n"
  74         "               }\n"
  75         "       gl_FragColor = texture2D(color, texcoord)*sum/count;\n"
  76         "}\n";
  77
  78 }
  79
  80 namespace Msp {
  81 namespace GL {
  82
  83 AmbientOcclusion::AmbientOcclusion(unsigned w, unsigned h, float depth_ratio):
  84         occlude_shader(vertex_shader, occlude_fs),
  85         occlude_shdata(occlude_shader),
  86         combine_shader(vertex_shader, combine_fs),
  87         combine_shdata(combine_shader),
  88         quad(VERTEX2)
  89 {
  90         occlusion.storage(GL::RGB, w, h);
  91         occlusion.set_min_filter(GL::NEAREST);
  92         occlusion.set_mag_filter(GL::NEAREST);
  93         fbo.attach(COLOR_ATTACHMENT0, occlusion, 0);
  94
  95         combine_texturing.attach(2, occlusion);
  96
  97         rotate_lookup.storage(GL::RGBA, 4, 4);
  98         rotate_lookup.set_min_filter(GL::NEAREST);
  99         rotate_lookup.set_mag_filter(GL::NEAREST);
 100         unsigned char data[64];
 101         for(unsigned i=0; i<16; ++i)
 102         {
 103                 float a = ((i*541)%16)*M_PI/32;
 104                 float c = cos(a);
 105                 float s = sin(a);
 106                 data[i*3  ] = static_cast<unsigned char>(127+c*127);
 107                 data[i*3+1] = static_cast<unsigned char>(127+s*127);
 108                 data[i*3+2] = static_cast<unsigned char>(127-s*127);
 109                 data[i*3+4] = static_cast<unsigned char>(127+c*127);
 110         }
 111         rotate_lookup.image(0, GL::RGBA, GL::UNSIGNED_BYTE, data);
 112
 113         occlude_texturing.attach(1, rotate_lookup);
 114
 115         occlude_shdata.uniform("depth", 0);
 116         occlude_shdata.uniform("rotate", 1);
 117         occlude_shdata.uniform("screen_size", w, h);
 118
 119         combine_shdata.uniform("color", 1);
 120         combine_shdata.uniform("depth", 0);
 121         combine_shdata.uniform("occlusion", 2);
 122         combine_shdata.uniform("screen_size", w, h);
 123
 124         set_depth_ratio(depth_ratio);
 125         set_darkness(1.5);
 126
 127         MeshBuilder bld(quad);
 128         bld.begin(TRIANGLE_STRIP);
 129         bld.vertex(-1, 1);
 130         bld.vertex(-1, -1);
 131         bld.vertex(1, 1);
 132         bld.vertex(1, -1);
 133         bld.end();
 134 }
 135
 136 void AmbientOcclusion::set_depth_ratio(float depth_ratio)
 137 {
 138         depth_ratio = 1/depth_ratio;
 139
 140         occlude_shdata.uniform("depth_ratio", depth_ratio, 1+depth_ratio);
 141         combine_shdata.uniform("depth_ratio", depth_ratio, 1+depth_ratio);
 142 }
 143
 144 void AmbientOcclusion::set_darkness(float darkness)
 145 {
 146         occlude_shdata.uniform("darkness", darkness);
 147 }
 148
 149 void AmbientOcclusion::render(const Texture2D &color, const Texture2D &depth)
 150 {
 151         occlude_texturing.attach(0, depth);
 152         combine_texturing.attach(0, depth);
 153         combine_texturing.attach(1, color);
 154
 155         Bind unbind_dtest(static_cast<DepthTest *>(0), true);
 156         Bind unbind_blend(static_cast<Blend *>(0), true);
 157
 158         {
 159                 GL::Bind bind_fbo(fbo, true);
 160                 GL::Bind bind_tex(occlude_texturing);
 161                 GL::Bind bind_shader(occlude_shader);
 162                 occlude_shdata.apply();
 163                 quad.draw();
 164         }
 165
 166         GL::Bind bind_tex(combine_texturing);
 167         GL::Bind bind_shader(combine_shader);
 168         combine_shdata.apply();
 169         quad.draw();
 170 }
 171
 172 } // namespace GL
 173 } // namespace Msp