ELI5: Explain Like I'm 5

Geometry pipelines

A geometry pipeline is a process of turning 3D shapes (like cubes, spheres, and pyramids) into 2D image that you see on a screen when you play a video game.

Think of it like this: when you draw a picture on a piece of paper, you use a pencil or pen to create lines and shapes that make up the image. The same thing happens in a video game. Except, instead of drawing with a pen, a computer uses math to make the shapes and lines on your screen.

The geometry pipeline has four steps:

1. Vertex processing: This is where the 3D shapes are created and updated with things like color, texture, reflection, and lighting. Each shape is made up of lots of tiny dots called "vertices.”

2. Rasterization: This step takes the 3D shapes and turns them into flat 2D triangles, which make up the surfaces you see on screen.

3. Pixel shading: Now that the shapes are in 2D, the computer fills in each triangle with the right color, brightness, texture, and shadow. This is called shading.

4. Output merging: Finally, the computer takes all the shaded triangles and puts them together to create the final image that you see on your screen. This is called merging.

So, to put it simply, a geometry pipeline is a computer process that takes 3D shapes, turns them into 2D shapes, fills in color and texture, and puts them together to create the final image you see on your screen when playing a video game.