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)*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         combine_shader(vertex_shader, combine_fs),
  86         quad(VERTEX2)
  87 {
  88         occlusion.storage(GL::RGB, w, h);
  89         occlusion.set_min_filter(GL::NEAREST);
  90         occlusion.set_mag_filter(GL::NEAREST);
  91         fbo.attach(COLOR_ATTACHMENT0, occlusion, 0);
  92
  93         combine_texturing.attach(2, occlusion);
  94
  95         rotate_lookup.storage(GL::RGBA, 4, 4);
  96         rotate_lookup.set_min_filter(GL::NEAREST);
  97         rotate_lookup.set_mag_filter(GL::NEAREST);
  98         unsigned char data[64];
  99         for(unsigned i=0; i<16; ++i)
 100         {
 101                 float a = ((i*541)%16)*M_PI/32;
 102                 float c = cos(a);
 103                 float s = sin(a);
 104                 data[i*3  ] = static_cast<unsigned char>(127+c*127);
 105                 data[i*3+1] = static_cast<unsigned char>(127+s*127);
 106                 data[i*3+2] = static_cast<unsigned char>(127-s*127);
 107                 data[i*3+4] = static_cast<unsigned char>(127+c*127);
 108         }
 109         rotate_lookup.image(0, GL::RGBA, GL::UNSIGNED_BYTE, data);
 110
 111         occlude_texturing.attach(1, rotate_lookup);
 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
 117         combine_shdata.uniform(combine_shader.get_uniform_location("color"), 1);
 118         combine_shdata.uniform(combine_shader.get_uniform_location("depth"), 0);
 119         combine_shdata.uniform(combine_shader.get_uniform_location("occlusion"), 2);
 120         combine_shdata.uniform(combine_shader.get_uniform_location("screen_size"), w, h);
 121
 122         set_depth_ratio(depth_ratio);
 123         set_darkness(1.5);
 124
 125         MeshBuilder bld(quad);
 126         bld.begin(TRIANGLE_STRIP);
 127         bld.vertex(-1, 1);
 128         bld.vertex(-1, -1);
 129         bld.vertex(1, 1);
 130         bld.vertex(1, -1);
 131         bld.end();
 132 }
 133
 134 void AmbientOcclusion::set_depth_ratio(float depth_ratio)
 135 {
 136         depth_ratio = 1/depth_ratio;
 137
 138         occlude_shdata.uniform(occlude_shader.get_uniform_location("depth_ratio"), depth_ratio, 1+depth_ratio);
 139         combine_shdata.uniform(combine_shader.get_uniform_location("depth_ratio"), depth_ratio, 1+depth_ratio);
 140 }
 141
 142 void AmbientOcclusion::set_darkness(float darkness)
 143 {
 144         occlude_shdata.uniform(occlude_shader.get_uniform_location("darkness"), darkness);
 145 }
 146
 147 void AmbientOcclusion::render(const Texture2D &color, const Texture2D &depth)
 148 {
 149         occlude_texturing.attach(0, depth);
 150         combine_texturing.attach(0, depth);
 151         combine_texturing.attach(1, color);
 152
 153         Bind unbind_dtest(static_cast<DepthTest *>(0), true);
 154         Bind unbind_blend(static_cast<Blend *>(0), true);
 155
 156         {
 157                 GL::Bind bind_fbo(fbo, true);
 158                 GL::Bind bind_tex(occlude_texturing);
 159                 GL::Bind bind_shader(occlude_shader);
 160                 occlude_shdata.apply();
 161                 quad.draw();
 162         }
 163
 164         GL::Bind bind_tex(combine_texturing);
 165         GL::Bind bind_shader(combine_shader);
 166         combine_shdata.apply();
 167         quad.draw();
 168 }
 169
 170 } // namespace GL
 171 } // namespace Msp