source/render/occludedscene.cpp

   1 #include <algorithm>
   2 #include <msp/gl/extensions/arb_occlusion_query.h>
   3 #include <msp/gl/extensions/arb_occlusion_query2.h>
   4 #include "camera.h"
   5 #include "occludedscene.h"
   6 #include "renderer.h"
   7 #include "resources.h"
   8 #include "sphere.h"
   9
  10 using namespace std;
  11
  12 namespace Msp {
  13 namespace GL {
  14
  15 OccludedScene::OccludedScene(Resources &resources):
  16         bounding_mesh(resources.get<Mesh>("_occluder.mesh")),
  17         bounding_shader(resources.get<Program>("_occluder.glsl.shader")),
  18         occluder_min_size(0.25f),
  19         cache_dirty(false)
  20 {
  21         static Require req(ARB_occlusion_query);
  22         static Require req2(ARB_occlusion_query2);
  23 }
  24
  25 OccludedScene::~OccludedScene()
  26 {
  27         vector<unsigned> queries;
  28         queries.reserve(occluded_cache.size());
  29         for(OccludedArray::iterator i=occluded_cache.begin(); i!=occluded_cache.end(); ++i)
  30                 queries.push_back(i->query);
  31         glDeleteQueries(queries.size(), &queries[0]);
  32 }
  33
  34 void OccludedScene::add(Renderable &r)
  35 {
  36         renderables.insert(&r);
  37         cache_dirty = true;
  38 }
  39
  40 void OccludedScene::remove(Renderable &r)
  41 {
  42         renderables.erase(&r);
  43         cache_dirty = true;
  44 }
  45
  46 void OccludedScene::populate_cache() const
  47 {
  48         if(!cache_dirty)
  49                 return;
  50
  51         if(occluded_cache.size()<renderables.size())
  52         {
  53                 unsigned old_size = occluded_cache.size();
  54                 occluded_cache.resize(renderables.size());
  55                 vector<unsigned> new_queries(occluded_cache.size()-old_size);
  56                 glGenQueries(new_queries.size(), &new_queries[0]);
  57                 for(unsigned i=0; i<new_queries.size(); ++i)
  58                         occluded_cache[old_size+i].query = new_queries[i];
  59         }
  60
  61         OccludedArray::iterator j = occluded_cache.begin();
  62         for(RenderableSet::iterator i=renderables.begin(); i!=renderables.end(); ++i, ++j)
  63                 j->renderable = *i;
  64         for(; j!=occluded_cache.end(); ++j)
  65         {
  66                 j->renderable = 0;
  67                 j->in_frustum = false;
  68         }
  69
  70         cache_dirty = false;
  71 }
  72
  73 void OccludedScene::setup_frame(Renderer &renderer)
  74 {
  75         populate_cache();
  76         for(OccludedArray::const_iterator i=occluded_cache.begin(); i!=occluded_cache.end(); ++i)
  77                 i->renderable->setup_frame(renderer);
  78 }
  79
  80 void OccludedScene::finish_frame()
  81 {
  82         for(OccludedArray::const_iterator i=occluded_cache.begin(); i!=occluded_cache.end(); ++i)
  83                 i->renderable->finish_frame();
  84 }
  85
  86 void OccludedScene::render(Renderer &renderer, Tag tag) const
  87 {
  88         if(renderables.empty())
  89                 return;
  90
  91         populate_cache();
  92
  93         const Camera *camera = renderer.get_camera();
  94         if(!camera)
  95         {
  96                 for(OccludedArray::const_iterator i=occluded_cache.begin(); i!=occluded_cache.end(); ++i)
  97                         renderer.render(*i->renderable, tag);
  98                 return;
  99         }
 100
 101         const Vector3 &camera_pos = camera->get_position();
 102         const Vector3 &look_dir = camera->get_look_direction();
 103         float near_clip = camera->get_near_clip();
 104         float frustum_h = tan(camera->get_field_of_view()/2.0f)*2.0f;
 105
 106         // Perform frustum culling and render any major occluders
 107         bool use_frustum = setup_frustum(renderer);
 108         for(OccludedArray::iterator i=occluded_cache.begin(); (i!=occluded_cache.end() && i->renderable); ++i)
 109         {
 110                 i->in_frustum = (!use_frustum || !frustum_cull(*i->renderable));
 111                 if(!i->in_frustum)
 112                         continue;
 113
 114                 const Matrix *matrix = i->renderable->get_matrix();
 115                 i->bounding_sphere = i->renderable->get_bounding_sphere();
 116                 if(matrix && i->bounding_sphere)
 117                 {
 118                         float depth = dot(*matrix*i->bounding_sphere->get_center()-camera_pos, look_dir);
 119                         float size = i->bounding_sphere->get_radius()*2/max(depth, near_clip);
 120                         i->occluder = (size>frustum_h*occluder_min_size);
 121                 }
 122                 else
 123                         // If the size can't be calculated, treat it as occluder
 124                         i->occluder = true;
 125
 126                 if(i->occluder)
 127                         renderer.render(*i->renderable, tag);
 128         }
 129
 130         // Move all objects within the frustum to the beginning of the array
 131         for(OccludedArray::iterator i=occluded_cache.begin(), j=i+renderables.size()-1; i!=j; )
 132         {
 133                 if(i->in_frustum)
 134                         ++i;
 135                 else if(j->in_frustum)
 136                         swap(*i, *j);
 137                 else
 138                         --j;
 139         }
 140
 141         {
 142                 Renderer::Push push(renderer);
 143                 renderer.set_shader_program(&bounding_shader);
 144
 145                 glColorMask(false, false, false, false);
 146                 glDepthMask(false);
 147
 148                 // Fire off the occlusion queries
 149                 for(OccludedArray::const_iterator i=occluded_cache.begin(); (i!=occluded_cache.end() && i->in_frustum); ++i)
 150                         if(!i->occluder)
 151                         {
 152                                 glBeginQuery(GL_ANY_SAMPLES_PASSED, i->query);
 153                                 Renderer::Push push2(renderer);
 154                                 renderer.transform(Matrix(*i->renderable->get_matrix())
 155                                         .translate(i->bounding_sphere->get_center())
 156                                         .scale(i->bounding_sphere->get_radius()));
 157                                 bounding_mesh.draw(renderer);
 158                                 glEndQuery(GL_ANY_SAMPLES_PASSED);
 159                         }
 160
 161                 glColorMask(true, true, true, true);
 162                 glDepthMask(true);
 163         }
 164
 165         // Render anything that has a chance of being visible
 166         for(OccludedArray::const_iterator i=occluded_cache.begin(); (i!=occluded_cache.end() && i->in_frustum); ++i)
 167                 if(!i->occluder)
 168                 {
 169                         unsigned any_passed = 0;
 170                         glGetQueryObjectuiv(i->query, GL_QUERY_RESULT, &any_passed);
 171                         if(any_passed)
 172                                 renderer.render(*i->renderable, tag);
 173                 }
 174 }
 175
 176
 177 OccludedScene::OccludedRenderable::OccludedRenderable():
 178         renderable(0),
 179         bounding_sphere(0),
 180         in_frustum(false),
 181         occluder(false),
 182         query(0)
 183 { }
 184
 185 } // namespace GL
 186 } // namespace Msp