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