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