source/ambientocclusion.cpp

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