How to download and setup js-smallpt
Open terminal and run command
                                            git clone https://github.com/matt77hias/js-smallpt.git
                                        
                                        git clone is used to create a copy or clone of js-smallpt repositories.
                                        You pass git clone a repository URL. it supports a few different network protocols and corresponding URL formats.
Also you may download zip file with js-smallpt https://github.com/matt77hias/js-smallpt/archive/master.zip
Or simply clone js-smallpt with SSH
                                            [email protected]:matt77hias/js-smallpt.git                                    
                                    If you have some problems with js-smallpt
You may open issue on js-smallpt support forum (system) here: https://github.com/matt77hias/js-smallpt/issuesSimilar to js-smallpt repositories
Here you may see js-smallpt alternatives and analogs
spritejs tinyrenderer appleseed yii2-render-many tangram pixijs bgfx Texture rendertron webglstudio.js mapnik asm-dom rust-doom react-tv gg herebedragons Glitter phenomenon ScriptableRenderPipeline Nidium Intrinsic armory PdfViewPager ShaderGraph ogre two WickedEngine Game-Programmer-Study-Notes glumpy ascii_art