Trial includes support for simple 2D parallax backgrounds via the parallax-background entity. You can also stack multiple parallax background entities to create a greater sense of depth. Each background instance takes either a :texture initarg, or a :default-background initarg, which can contain the same keyword arguments as change-background:
:texture
The texture to display as a parallax
:scaling
The scaling factor of the background texture as a vec2
:parallax
The parallax movement speed factor as a vec2
:offset
The base display offset of the background compared to the camera as a vec2
:unit
The parallax background entity to update. Only needed when calling change-background directly.
These parameters should give you complete control over the display behaviour of the background.