// "Lost Astronaut" // by Julien Vergnaud @duvengar-2017 // License Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. // // see it running on shadertoy https://www.shadertoy.com/view/Mlfyz4 // ==================================================================== // this shader is inspired by iq's "Raymarching - Primitives's", // https://www.shadertoy.com/view/Xds3zN // and article, // http://iquilezles.org/www/articles/distfunctions/distfunctions.htm // and Shane's "Transparent 3D Noise" , // https://www.shadertoy.com/view/lstGRB // ====================================================================