source/render/occludedscene.cpp

   1 #include <algorithm>
   2 #include "camera.h"
   3 #include "mesh.h"
   4 #include "occludedscene.h"
   5 #include "program.h"
   6 #include "renderer.h"
   7 #include "resources.h"
   8
   9 using namespace std;
  10
  11 namespace Msp {
  12 namespace GL {
  13
  14 OccludedScene::OccludedScene():
  15         bounding_mesh(Resources::get_global().get<Mesh>("_occluder.mesh")),
  16         bounding_shader(Resources::get_global().get<Program>("_occluder.glsl.shader")),
  17         no_depth_write(LEQUAL, false),
  18         occluder_min_size(0.25f),
  19         queries(OCCLUSION_QUERY, 0),
  20         cache_dirty(false)
  21 {
  22         no_color_write.write_mask = WRITE_NONE;
  23 }
  24
  25 void OccludedScene::add(Renderable &r)
  26 {
  27         renderables.insert(&r);
  28         cache_dirty = true;
  29 }
  30
  31 void OccludedScene::remove(Renderable &r)
  32 {
  33         renderables.erase(&r);
  34         cache_dirty = true;
  35 }
  36
  37 void OccludedScene::populate_cache() const
  38 {
  39         if(!cache_dirty)
  40                 return;
  41
  42         if(queries.get_size()<renderables.size())
  43                 queries.resize(renderables.size());
  44         if(occluded_cache.size()<renderables.size())
  45                 occluded_cache.resize(renderables.size());
  46
  47         auto j = occluded_cache.begin();
  48         for(Renderable *r: renderables)
  49                 j++->renderable = r;
  50         for(; j!=occluded_cache.end(); ++j)
  51         {
  52                 j->renderable = 0;
  53                 j->in_frustum = false;
  54         }
  55
  56         cache_dirty = false;
  57 }
  58
  59 void OccludedScene::setup_frame(Renderer &renderer)
  60 {
  61         populate_cache();
  62         for(const OccludedRenderable &o: occluded_cache)
  63                 o.renderable->setup_frame(renderer);
  64 }
  65
  66 void OccludedScene::finish_frame()
  67 {
  68         for(const OccludedRenderable &o: occluded_cache)
  69                 o.renderable->finish_frame();
  70 }
  71
  72 void OccludedScene::render(Renderer &renderer, Tag tag) const
  73 {
  74         if(renderables.empty())
  75                 return;
  76
  77         populate_cache();
  78
  79         const Camera *camera = renderer.get_camera();
  80         if(!camera)
  81         {
  82                 for(const OccludedRenderable &o: occluded_cache)
  83                         renderer.render(*o.renderable, tag);
  84                 return;
  85         }
  86
  87         const Vector3 &camera_pos = camera->get_position();
  88         const Vector3 &look_dir = camera->get_look_direction();
  89         float near_clip = camera->get_near_clip();
  90         float frustum_h = tan(camera->get_field_of_view()/2.0f)*2.0f;
  91
  92         // Perform frustum culling and render any major occluders
  93         bool use_frustum = setup_frustum(renderer);
  94         for(auto i=occluded_cache.begin(); (i!=occluded_cache.end() && i->renderable); ++i)
  95         {
  96                 i->in_frustum = (!use_frustum || !frustum_cull(*i->renderable));
  97                 if(!i->in_frustum)
  98                         continue;
  99
 100                 const Matrix *matrix = i->renderable->get_matrix();
 101                 i->bounding_sphere = i->renderable->get_bounding_sphere();
 102                 if(matrix && i->bounding_sphere)
 103                 {
 104                         float depth = dot(*matrix*i->bounding_sphere->get_center()-camera_pos, look_dir);
 105                         float size = i->bounding_sphere->get_radius()*2/max(depth, near_clip);
 106                         i->occluder = (size>frustum_h*occluder_min_size);
 107                 }
 108                 else
 109                         // If the size can't be calculated, treat it as occluder
 110                         i->occluder = true;
 111
 112                 if(i->occluder)
 113                         renderer.render(*i->renderable, tag);
 114         }
 115
 116         // Move all objects within the frustum to the beginning of the array
 117         for(auto i=occluded_cache.begin(), j=i+renderables.size()-1; i!=j; )
 118         {
 119                 if(i->in_frustum)
 120                         ++i;
 121                 else if(j->in_frustum)
 122                         swap(*i, *j);
 123                 else
 124                         --j;
 125         }
 126
 127         {
 128                 Renderer::Push push(renderer);
 129                 renderer.set_shader_program(&bounding_shader);
 130
 131                 renderer.set_blend(&no_color_write);
 132                 // XXX Preserve existing depth test predicate
 133                 renderer.set_depth_test(&no_depth_write);
 134
 135                 // Fire off the occlusion queries
 136                 for(auto i=occluded_cache.begin(); (i!=occluded_cache.end() && i->in_frustum); ++i)
 137                         if(!i->occluder)
 138                         {
 139                                 QueryPool::Activate activate_query(renderer, queries, i-occluded_cache.begin());
 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                         }
 146         }
 147
 148         // Render anything that has a chance of being visible
 149         for(auto i=occluded_cache.begin(); (i!=occluded_cache.end() && i->in_frustum); ++i)
 150                 if(!i->occluder && queries.get_result(i-occluded_cache.begin()))
 151                         renderer.render(*i->renderable, tag);
 152 }
 153
 154
 155 OccludedScene::OccludedRenderable::OccludedRenderable():
 156         renderable(0),
 157         bounding_sphere(0),
 158         in_frustum(false),
 159         occluder(false)
 160 { }
 161
 162 } // namespace GL
 163 } // namespace Msp