source/ambientocclusion.cpp

   1 /* $Id$
   2
   3 This file is part of libmspgl
   4 Copyright © 2010  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)*0.02;\n"
  35         "       float depth_avg = 0.0;\n"
  36         "       for(int i=0; i<=3; ++i)\n"
  37         "               for(int j=0; j<=3; ++j)\n"
  38         "               {\n"
  39         "                       vec2 offs = transform*vec2(float(i)-1.5, float(j)-1.5);\n"
  40         "                       depth_avg += depth_ratio.x/(texture2D(depth, texcoord+offs).r-depth_ratio.y);\n"
  41         "               }\n"
  42         "       depth_avg /= 16;\n"
  43         "       float sample = depth_ratio.x/(texture2D(depth, texcoord).r-depth_ratio.y);\n"
  44         "       float diff = sample-depth_avg;\n"
  45         "       float shade = min(diff*darkness, 0.0)+1.0;\n"
  46         "       gl_FragColor = vec4(shade, 0.0, 0.0, 1.0);\n"
  47         "}\n";
  48
  49 const char combine_fs[] =
  50         "uniform sampler2D color;\n"
  51         "uniform sampler2D depth;\n"
  52         "uniform sampler2D occlusion;\n"
  53         "uniform vec2 screen_size;\n"
  54         "uniform vec2 depth_ratio;\n"
  55         "uniform float edge_threshold;\n"
  56         "varying vec2 texcoord;\n"
  57         "void main()\n"
  58         "{\n"
  59         "       float sample = depth_ratio.x/(texture2D(depth, texcoord).r-depth_ratio.y);\n"
  60         "       float sum = 1.0;\n"
  61         "       float count = 1.0;\n"
  62         "       for(int i=0; i<=3; ++i)\n"
  63         "               for(int j=0; j<=3; ++j)\n"
  64         "               {\n"
  65         "                       vec2 offs = vec2(float(i)-1.5, float(j)-1.5)/screen_size;\n"
  66         "                       float depth = depth_ratio.x/(texture2D(depth, texcoord+offs).r-depth_ratio.y);\n"
  67         "                       if(abs(depth-sample)<edge_threshold)\n"
  68         "                       {\n"
  69         "                               sum += texture2D(occlusion, texcoord+offs).r;\n"
  70         "                               count += 1.0;\n"
  71         "                       }\n"
  72         "               }\n"
  73         "       gl_FragColor = texture2D(color, texcoord)*sum/count;\n"
  74         "}\n";
  75
  76 }
  77
  78 namespace Msp {
  79 namespace GL {
  80
  81 AmbientOcclusion::AmbientOcclusion(unsigned w, unsigned h, float depth_ratio):
  82         occlude_shader(vertex_shader, occlude_fs),
  83         combine_shader(vertex_shader, combine_fs),
  84         quad(VERTEX2)
  85 {
  86         occlusion.storage(GL::RGB, w, h);
  87         occlusion.set_min_filter(GL::NEAREST);
  88         occlusion.set_mag_filter(GL::NEAREST);
  89         fbo.attach(COLOR_ATTACHMENT0, occlusion, 0);
  90
  91         combine_texturing.attach(2, occlusion);
  92
  93         rotate_lookup.storage(GL::RGBA, 4, 4);
  94         rotate_lookup.set_min_filter(GL::NEAREST);
  95         rotate_lookup.set_mag_filter(GL::NEAREST);
  96         unsigned char data[64];
  97         for(unsigned i=0; i<16; ++i)
  98         {
  99                 float a = ((i*541)%16)*M_PI/32;
 100                 float c = cos(a);
 101                 float s = sin(a);
 102                 data[i*3  ] = static_cast<unsigned char>(127+c*127);
 103                 data[i*3+1] = static_cast<unsigned char>(127+s*127);
 104                 data[i*3+2] = static_cast<unsigned char>(127-s*127);
 105                 data[i*3+4] = static_cast<unsigned char>(127+c*127);
 106         }
 107         rotate_lookup.image(0, GL::RGBA, GL::UNSIGNED_BYTE, data);
 108
 109         occlude_texturing.attach(1, rotate_lookup);
 110
 111         depth_ratio = 1/depth_ratio;
 112
 113         occlude_shdata.uniform(occlude_shader.get_uniform_location("depth"), 0);
 114         occlude_shdata.uniform(occlude_shader.get_uniform_location("rotate"), 1);
 115         occlude_shdata.uniform(occlude_shader.get_uniform_location("screen_size"), w, h);
 116         occlude_shdata.uniform(occlude_shader.get_uniform_location("depth_ratio"), depth_ratio, 1+depth_ratio);
 117
 118         combine_shdata.uniform(combine_shader.get_uniform_location("color"), 1);
 119         combine_shdata.uniform(combine_shader.get_uniform_location("depth"), 0);
 120         combine_shdata.uniform(combine_shader.get_uniform_location("occlusion"), 2);
 121         combine_shdata.uniform(combine_shader.get_uniform_location("screen_size"), w, h);
 122         combine_shdata.uniform(combine_shader.get_uniform_location("depth_ratio"), depth_ratio, 1+depth_ratio);
 123         combine_shdata.uniform(combine_shader.get_uniform_location("edge_threshold"), 0.05f);
 124
 125         set_darkness(15);
 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_darkness(float d)
 137 {
 138         darkness = d;
 139         occlude_shdata.uniform(occlude_shader.get_uniform_location("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