source/ambientocclusion.cpp

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