Add an effect for rendering a procedurally generated sky

[libs/gl.git] / source / effects / sky.h

diff --git a/source/effects/sky.h b/source/effects/sky.h
new file mode 100644 (file)
index 0000000..eb4f618
--- /dev/null
+++ b/source/effects/sky.h
@@ -0,0 +1,73 @@
+#ifndef MSP_GL_SKY_H_
+#define MSP_GL_SKY_H_
+
+#include "effect.h"
+#include "framebuffer.h"
+#include "programdata.h"
+#include "texture2d.h"
+
+namespace Msp {
+namespace GL {
+
+class Mesh;
+class Light;
+class Program;
+
+/**
+Renders a procedurally generated sky at the background.  Based on the paper
+"A Scalable and Production Ready Sky and Atmosphere Rendering Technique" by
+Sébastien Hillaire (https://sebh.github.io/publications/egsr2020.pdf).
+*/
+class Sky: public Effect
+{
+public:
+       struct Planet
+       {
+               Color rayleigh_scatter;
+               Color mie_scatter;
+               Color mie_absorb;
+               Color ozone_absorb;
+               float rayleigh_density_decay;
+               float mie_density_decay;
+               float ozone_band_center;
+               float ozone_band_extent;
+               float atmosphere_thickness;
+               float planet_radius;
+               Color ground_albedo;
+
+               Planet();
+
+               static Planet earth();
+       };
+
+private:
+       const Light &sun;
+       Texture2D transmittance_lookup;
+       const Program &transmittance_shprog;
+       Framebuffer transmittance_fbo;
+       bool transmittance_lookup_dirty;
+       Texture2D distant;
+       const Program &distant_shprog;
+       Framebuffer distant_fbo;
+       const Mesh &fullscreen_mesh;
+       const Program &backdrop_shprog;
+       const Sampler &sampler;
+       const Sampler &wrap_sampler;
+       mutable ProgramData shdata;
+       bool rendered;
+
+public:
+       Sky(Resources &, Renderable &, const Light &);
+
+       void set_planet(const Planet &);
+       void set_view_height(float);
+
+       virtual void setup_frame(Renderer &);
+       virtual void finish_frame();
+       virtual void render(Renderer &, Tag = Tag()) const;
+};
+
+} // namespace GL
+} // namespace Msp
+
+#endif