There are a couple things you should know before we get started. WebGL is a JavaScript API that renders 3D content to an HTML5 canvas. It does this by using two scripts that are known in the "3D world" asShaders. The two shaders are:

  • The vertex shader
  • The fragment shader

Now don’t get too nervous when you hear these names; it’s just a fancy way of saying, "position calculator" and "color chooser" respectively. The fragment shader is the easier one to understand; it simply tells WebGL what color a given point on your model should be. The vertex shader is a little more technical, but basically it converts the points in your 3D models into 2D coordinates. Because all computer monitors are flat 2D surfaces, and when you see 3D objects on your screen, they are merely an illusion of perspective.

If you want to know exactly how this calculation works, you’d need to ask a mathematician, because it uses advanced 4 x 4 matrix multiplications, which are a bit beyond the ‘Essentials’ tutorial. Luckily, you don’t have to know how it works because WebGL will take care of most of it. So let’s get started.

https://net.tutsplus.com/tutorials/webgl-essentials-part-i/

Очень хорошая статья для тех, кто хочет начать пользоваться WebGL.