Why do textures float in PlayStation 1 games?

Games from the PlayStation 1 era are remembered by many for their unique graphics: both gritty and charming. Portal howtogeek.com Tellwhy games on the PS1 looked like this, and where the famous “floating” textures came from.

The performance of modern GPUs is usually measured in Floating Point Operations Per Second. In other words, this unit measures how many floating point operations a system can perform per second. The original PlayStation’s GPU had zero Floating Point Operations Per Second because it had no floating point unit.

PS1 uses fixed-point integration to calculate vertices. In turn, a vertex is a point where at least two lines converge: polygons in three-dimensional graphics are usually composed of triangles. However, 3D models are composed of many polygons, so when an object on the screen moves, vertices need to be calculated in volume space.

Because the system has a finite number of integrals to work with; any vertex position that is not an integral will be skipped. As a result, sometimes polygons will transition abruptly between positions with some motion. For example, if a character is standing still, but an idle animation is playing, the polygons will appear to shake on the screen.

The PS1 also had no hardware Z-buffer – it was necessary to calculate the distance of objects from the game camera. Since developers couldn’t take advantage of the built-in buffer, they had to find their own solutions. Most of the time, they were very economical. As a result, PS1 games often had slight object sorting errors: polygons that should have been hidden would periodically appear and then disappear from view.

Without a Z-buffer, developers were also forced to use unified texture mapping – the perspective projection of 3D objects would look incorrect. For comparison, the Nintendo 64 and some other platforms had a Z-buffer, which allowed the use of another texture mapping method – mipmapping. It applied multiple textures to an object at the same time and changed them depending on the distance, which increased the clarity and stability of the moving picture.