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 "sphere.h"
   8
   9 using namespace std;
  10
  11 namespace Msp {
  12 namespace GL {
  13
  14 OccludedScene::OccludedScene():
  15         bounding_mesh((VERTEX3, NORMAL3)),
  16         bounding_shader("occluder.glsl"),
  17         occluder_min_size(0.25f),
  18         cache_dirty(false)
  19 {
  20         static Require req(ARB_occlusion_query);
  21         static Require req2(ARB_occlusion_query2);
  22
  23         /* Use a slightly larger radius to ensure that all parts of the renderable
  24         fit inside the icosahedron */
  25         IcoSphereBuilder(1.26f, 1).build(bounding_mesh);
  26         bounding_mesh.set_winding(&WindingTest::counterclockwise());
  27 }
  28
  29 OccludedScene::~OccludedScene()
  30 {
  31         vector<unsigned> queries;
  32         queries.reserve(occluded_cache.size());
  33         for(OccludedArray::iterator i=occluded_cache.begin(); i!=occluded_cache.end(); ++i)
  34                 queries.push_back(i->query);
  35         glDeleteQueries(queries.size(), &queries[0]);
  36 }
  37
  38 void OccludedScene::add(Renderable &r)
  39 {
  40         renderables.insert(&r);
  41         cache_dirty = true;
  42 }
  43
  44 void OccludedScene::remove(Renderable &r)
  45 {
  46         renderables.erase(&r);
  47         cache_dirty = true;
  48 }
  49
  50 void OccludedScene::populate_cache() const
  51 {
  52         if(!cache_dirty)
  53                 return;
  54
  55         if(occluded_cache.size()<renderables.size())
  56         {
  57                 unsigned old_size = occluded_cache.size();
  58                 occluded_cache.resize(renderables.size());
  59                 vector<unsigned> new_queries(occluded_cache.size()-old_size);
  60                 glGenQueries(new_queries.size(), &new_queries[0]);
  61                 for(unsigned i=0; i<new_queries.size(); ++i)
  62                         occluded_cache[old_size+i].query = new_queries[i];
  63         }
  64
  65         OccludedArray::iterator j = occluded_cache.begin();
  66         for(RenderableSet::iterator i=renderables.begin(); i!=renderables.end(); ++i, ++j)
  67                 j->renderable = *i;
  68         for(; j!=occluded_cache.end(); ++j)
  69         {
  70                 j->renderable = 0;
  71                 j->in_frustum = false;
  72         }
  73
  74         cache_dirty = false;
  75 }
  76
  77 void OccludedScene::setup_frame(Renderer &renderer)
  78 {
  79         populate_cache();
  80         for(OccludedArray::const_iterator i=occluded_cache.begin(); i!=occluded_cache.end(); ++i)
  81                 i->renderable->setup_frame(renderer);
  82 }
  83
  84 void OccludedScene::finish_frame()
  85 {
  86         for(OccludedArray::const_iterator i=occluded_cache.begin(); i!=occluded_cache.end(); ++i)
  87                 i->renderable->finish_frame();
  88 }
  89
  90 void OccludedScene::render(Renderer &renderer, const Tag &tag) const
  91 {
  92         if(renderables.empty())
  93                 return;
  94
  95         populate_cache();
  96
  97         const Camera *camera = renderer.get_camera();
  98         if(!camera)
  99         {
 100                 for(OccludedArray::const_iterator i=occluded_cache.begin(); i!=occluded_cache.end(); ++i)
 101                         renderer.render(*i->renderable, tag);
 102                 return;
 103         }
 104
 105         const Vector3 &camera_pos = camera->get_position();
 106         const Vector3 &look_dir = camera->get_look_direction();
 107         float near_clip = camera->get_near_clip();
 108         float frustum_h = tan(camera->get_field_of_view()/2.0f)*2.0f;
 109
 110         // Perform frustum culling and render any major occluders
 111         bool use_frustum = setup_frustum(renderer);
 112         for(OccludedArray::iterator i=occluded_cache.begin(); (i!=occluded_cache.end() && i->renderable); ++i)
 113         {
 114                 i->in_frustum = (!use_frustum || !frustum_cull(*i->renderable));
 115                 if(!i->in_frustum)
 116                         continue;
 117
 118                 const Matrix *matrix = i->renderable->get_matrix();
 119                 i->bounding_sphere = i->renderable->get_bounding_sphere();
 120                 if(matrix && i->bounding_sphere)
 121                 {
 122                         float depth = dot(*matrix*i->bounding_sphere->get_center()-camera_pos, look_dir);
 123                         float size = i->bounding_sphere->get_radius()*2/max(depth, near_clip);
 124                         i->occluder = (size>frustum_h*occluder_min_size);
 125                 }
 126                 else
 127                         // If the size can't be calculated, treat it as occluder
 128                         i->occluder = true;
 129
 130                 if(i->occluder)
 131                         renderer.render(*i->renderable, tag);
 132         }
 133
 134         // Move all objects within the frustum to the beginning of the array
 135         for(OccludedArray::iterator i=occluded_cache.begin(), j=i+renderables.size()-1; i!=j; )
 136         {
 137                 if(i->in_frustum)
 138                         ++i;
 139                 else if(j->in_frustum)
 140                         swap(*i, *j);
 141                 else
 142                         --j;
 143         }
 144
 145         {
 146                 Renderer::Push push(renderer);
 147                 renderer.set_shader_program(&bounding_shader);
 148
 149                 glColorMask(false, false, false, false);
 150                 glDepthMask(false);
 151
 152                 // Fire off the occlusion queries
 153                 for(OccludedArray::const_iterator i=occluded_cache.begin(); (i!=occluded_cache.end() && i->in_frustum); ++i)
 154                         if(!i->occluder)
 155                         {
 156                                 glBeginQuery(GL_ANY_SAMPLES_PASSED, i->query);
 157                                 Renderer::Push push2(renderer);
 158                                 renderer.transform(Matrix(*i->renderable->get_matrix())
 159                                         .translate(i->bounding_sphere->get_center())
 160                                         .scale(i->bounding_sphere->get_radius()));
 161                                 bounding_mesh.draw(renderer);
 162                                 glEndQuery(GL_ANY_SAMPLES_PASSED);
 163                         }
 164
 165                 glColorMask(true, true, true, true);
 166                 glDepthMask(true);
 167         }
 168
 169         // Render anything that has a chance of being visible
 170         for(OccludedArray::const_iterator i=occluded_cache.begin(); (i!=occluded_cache.end() && i->in_frustum); ++i)
 171                 if(!i->occluder)
 172                 {
 173                         unsigned any_passed = 0;
 174                         glGetQueryObjectuiv(i->query, GL_QUERY_RESULT, &any_passed);
 175                         if(any_passed)
 176                                 renderer.render(*i->renderable, tag);
 177                 }
 178 }
 179
 180
 181 OccludedScene::OccludedRenderable::OccludedRenderable():
 182         renderable(0),
 183         bounding_sphere(0),
 184         in_frustum(false),
 185         occluder(false),
 186         query(0)
 187 { }
 188
 189 } // namespace GL
 190 } // namespace Msp