source/effects/sky.cpp

   1 #include <msp/geometry/hypersphere.h>
   2 #include <msp/geometry/ray.h>
   3 #include "directionallight.h"
   4 #include "error.h"
   5 #include "mesh.h"
   6 #include "renderer.h"
   7 #include "resources.h"
   8 #include "texture2d.h"
   9 #include "sky.h"
  10
  11 using namespace std;
  12
  13 namespace Msp {
  14 namespace GL {
  15
  16 Sky::Sky(Renderable &c, DirectionalLight &s):
  17         Effect(c),
  18         sun(s),
  19         transmittance_lookup(128, 64, (COLOR_ATTACHMENT,RGBA16F)),
  20         transmittance_shprog(Resources::get_global().get<Program>("_sky_transmittance.glsl.shader")),
  21         transmittance_lookup_dirty(true),
  22         distant(256, 128, (COLOR_ATTACHMENT,RGBA16F)),
  23         distant_shprog(Resources::get_global().get<Program>("_sky_distant.glsl.shader")),
  24         fullscreen_mesh(Resources::get_global().get<Mesh>("_fullscreen_quad.mesh")),
  25         backdrop_shprog(Resources::get_global().get<Program>("_sky_backdrop.glsl.shader")),
  26         sampler(Resources::get_global().get<Sampler>("_linear_clamp.samp")),
  27         wrap_sampler(Resources::get_global().get<Sampler>("_linear_clamp_v.samp")),
  28         dummy_texture(Resources::get_global().get<Texture>("_placeholder.png")),
  29         rendered(false)
  30 {
  31         shdata.uniform("n_steps", 50);
  32
  33         set_planet(Planet::earth());
  34         set_view_height(5.0f);
  35 }
  36
  37 void Sky::set_planet(const Planet &p)
  38 {
  39         planet = p;
  40         shdata.uniform("events.rayleigh_scatter", planet.rayleigh_scatter.r, planet.rayleigh_scatter.g, planet.rayleigh_scatter.b);
  41         shdata.uniform("events.mie_scatter", planet.mie_scatter.r, planet.mie_scatter.g, planet.mie_scatter.b);
  42         shdata.uniform("events.mie_absorb", planet.mie_absorb.r, planet.mie_absorb.g, planet.mie_absorb.b);
  43         shdata.uniform("events.ozone_absorb", planet.ozone_absorb.r, planet.ozone_absorb.g, planet.ozone_absorb.b);
  44         shdata.uniform("rayleigh_density_decay", planet.rayleigh_density_decay);
  45         shdata.uniform("mie_density_decay", planet.mie_density_decay);
  46         shdata.uniform("ozone_band_center", planet.ozone_band_center);
  47         shdata.uniform("ozone_band_extent", planet.ozone_band_extent);
  48         shdata.uniform("atmosphere_thickness", planet.atmosphere_thickness);
  49         shdata.uniform("planet_radius", planet.planet_radius);
  50         shdata.uniform("ground_albedo", planet.ground_albedo.r, planet.ground_albedo.g, planet.ground_albedo.b);
  51 }
  52
  53 void Sky::set_view_height(float h)
  54 {
  55         view_height = h;
  56         shdata.uniform("view_height", h);
  57 }
  58
  59 Color Sky::get_transmittance(const Vector3 &look_dir)
  60 {
  61         Vector3 pos(0.0f, 0.0f, view_height);
  62         Vector3 planet_center(0.0f, 0.0f, -planet.planet_radius);
  63
  64         Geometry::Ray<float, 3> ray(pos-planet_center, look_dir);
  65         Geometry::HyperSphere<float, 3> surface(planet.planet_radius);
  66         Geometry::SurfacePoint<float, 3> intersection;
  67         if(surface.get_intersections(ray, &intersection, 1))
  68                 return Color(0.0f);
  69
  70         Geometry::HyperSphere<float, 3> space(planet.planet_radius+planet.atmosphere_thickness);
  71         if(!space.get_intersections(ray, &intersection, 1))
  72                 return Color(1.0f);
  73
  74         float step_size = intersection.distance/50;
  75
  76         Color path_extinction(0.0f);
  77         for(unsigned i=0; i<50; ++i)
  78         {
  79                 Vector3 from_center = pos-planet_center;
  80                 float height = from_center.norm()-planet.planet_radius;
  81
  82                 Color rayleigh_scatter = planet.rayleigh_scatter*exp(height/planet.rayleigh_density_decay);
  83                 Color mie_scatter = planet.mie_scatter*exp(height/planet.mie_density_decay);
  84                 Color mie_absorb = planet.mie_absorb*exp(height/planet.mie_density_decay);
  85                 Color ozone_absorb = planet.ozone_absorb*max(1.0f-abs(height-planet.ozone_band_center)/planet.ozone_band_extent, 0.0f);
  86
  87                 path_extinction = path_extinction+(rayleigh_scatter+mie_scatter+mie_absorb+ozone_absorb)*step_size;
  88                 pos += look_dir*step_size;
  89         }
  90
  91         return Color(exp(-path_extinction.r), exp(-path_extinction.g), exp(-path_extinction.b));
  92 }
  93
  94 void Sky::setup_frame(Renderer &renderer)
  95 {
  96         if(rendered)
  97                 return;
  98
  99         rendered = true;
 100
 101         shdata.uniform("light_color", sun.get_color());
 102         shdata.uniform("light_dir", -sun.get_direction());
 103         sun.set_transmittance(get_transmittance(-sun.get_direction()));
 104
 105         {
 106                 Renderer::Push push(renderer);
 107
 108                 renderer.add_shader_data(shdata);
 109
 110                 if(transmittance_lookup_dirty)
 111                 {
 112                         transmittance_lookup_dirty = false;
 113                         renderer.set_pipeline_key(this);
 114                         renderer.set_framebuffer(&transmittance_lookup.get_framebuffer());
 115                         renderer.set_shader_program(&transmittance_shprog);
 116                         renderer.set_texture("transmittance_lookup", &dummy_texture, &sampler);
 117                         fullscreen_mesh.draw(renderer);
 118                 }
 119
 120                 renderer.set_pipeline_key(this, 1);
 121                 renderer.set_framebuffer(&distant.get_framebuffer());
 122                 renderer.set_shader_program(&distant_shprog);
 123                 renderer.set_texture("transmittance_lookup", &transmittance_lookup.get_target_texture(0), &sampler);
 124                 fullscreen_mesh.draw(renderer);
 125         }
 126
 127         content.setup_frame(renderer);
 128 }
 129
 130 void Sky::finish_frame()
 131 {
 132         if(rendered)
 133         {
 134                 rendered = false;
 135                 content.finish_frame();
 136         }
 137 }
 138
 139 void Sky::render(Renderer &renderer, Tag tag) const
 140 {
 141         content.render(renderer, tag);
 142
 143         if(!is_enabled_for_method(tag))
 144                 return;
 145
 146         Renderer::Push push(renderer);
 147
 148         renderer.set_pipeline_key(this, 2);
 149         renderer.set_shader_program(&backdrop_shprog, &shdata);
 150         renderer.set_texture("distant", &distant.get_target_texture(0), &wrap_sampler);
 151         fullscreen_mesh.draw(renderer);
 152 }
 153
 154 void Sky::set_debug_name(const string &name)
 155 {
 156 #ifdef DEBUG
 157         transmittance_lookup.set_debug_name(name+" [RT:transmittance]");
 158         distant.set_debug_name(name+" [RT:distant]");
 159         shdata.set_debug_name(name+" [UBO]");
 160 #else
 161         (void)name;
 162 #endif
 163 }
 164
 165
 166 Sky::Planet::Planet():
 167         rayleigh_scatter(0.0f),
 168         mie_scatter(0.0f),
 169         mie_absorb(0.0f),
 170         ozone_absorb(0.0f),
 171         rayleigh_density_decay(1e3f),
 172         mie_density_decay(1e3f),
 173         ozone_band_center(1e4f),
 174         ozone_band_extent(1e2f),
 175         atmosphere_thickness(2e4f),
 176         planet_radius(1e6f),
 177         ground_albedo(0.2f)
 178 { }
 179
 180 Sky::Planet Sky::Planet::earth()
 181 {
 182         Planet planet;
 183         planet.rayleigh_scatter = Color(5.802e-6f, 13.558e-6f, 33.1e-6f);
 184         planet.mie_scatter = Color(3.996e-6f, 3.996e-6f, 3.996e-6f);
 185         planet.mie_absorb = Color(4.4e-6f, 4.4e-6f, 4.4e-6f);
 186         planet.ozone_absorb = Color(0.65e-6f, 1.881e-6f, 0.085e-6f);
 187         planet.rayleigh_density_decay = -8e3f;
 188         planet.mie_density_decay = -1.2e3f;
 189         planet.ozone_band_center = 25e3f;
 190         planet.ozone_band_extent = 15e3f;
 191         planet.atmosphere_thickness = 1e5f;
 192         planet.planet_radius = 6.36e6f;
 193         return planet;
 194 }
 195
 196
 197 Sky *Sky::Template::create(const map<string, Renderable *> &renderables) const
 198 {
 199         Renderable *content = get_item(renderables, content_name);
 200         if(!content || !sun)
 201                 throw invalid_operation("Sky::Template::create");
 202
 203         RefPtr<Sky> sky = new Sky(*content, *sun);
 204         create_base(*sky);
 205
 206         return sky.release();
 207 }
 208
 209
 210 DataFile::Loader::ActionMap Sky::Template::Loader::shared_actions;
 211
 212 Sky::Template::Loader::Loader(Template &t, Collection &c):
 213         DerivedObjectLoader<Template, Effect::Template::Loader>(t, c)
 214 {
 215         set_actions(shared_actions);
 216 }
 217
 218 void Sky::Template::Loader::init_actions()
 219 {
 220         Effect::Template::Loader::init_actions();
 221         add("sun", &Template::sun);
 222 }
 223
 224 } // namespace GL
 225 } // namespace Msp