Earth was too edgy for me

The Warth texture was downloaded from NASA’s ‘Blue Marble’ picture gallery. I adjusted contrast and brightness but otherwise kept it as is. The default sphere mesh in Unity did not have enough triangles to make the Earth’s horizon smooth-looking. I created a new sphere mesh in Blender. I exported it to OBJ and imported it into Unity. To make the texture line up well I rotated until I saw that the equator intersected the right points in Africa, South America, and Indonesia.

Unity setup

I start by setting up the Unity scene, with a sphere mesh and good camera controls for testing.

Light shader

Accurate renderings of atmospheric scattering can be resource intensive. A ray-tracing example by Scratchapixel took a few seconds to render on a 2.5 GHz x86 CPU core. I want to make a simpler shader of the atmospheric scattering effect that will run on mobile hardware. My target is a Broadcom Capri 28155 System-on-a-chip with a 1.2 Ghz dual-core ARMv7 CPU and 1GB RAM. This SOC supports OpenGL ES 2.0 (equivalent to Shader Model 2) and has been used in, for example, the three years old Samsung Galaxy Core Plus and five years old Samsung Galaxy S II. OpenGL ES 2.0 is supported by most Android phones since 2010 when Android 2.2 released.