How do I visualize parallax layers in a level editor?

Question

I'm making a 2D game in Unity, but this would apply to any 2D game engine.

If I implement multiplane parallax with orthographic cameras, it is difficult to lay out the background layer's sprites and know where they will line up with sprites in other layers.

My first instinct was to use multiple cameras, one for each layer, and scale down the movement speed of cameras for background layers. This avoids having to move all background sprites every frame. The problem is that a layer that moves at half speed will take up half the space of the main layer when viewed in the editor. So it is difficult to know where to place sprites as you're laying out the game. The problem gets exponentially worse as you increase the number of layers.

How do I get around this? I've tried inversely scaling the layers by their intended movement speeds while working with them in the editor. That puts all background sprites in the correct locations relative to the main layer, but they're horribly distorted.

Do I need to just suck it up and constantly switch between the editor and the running game to test the parallax backgrounds?

Answer 1

I'm unfamiliar with Unity, so I cannot help you with specifics, but it sounds like what you need is to implement a GUI means of fine-tuning those values during run-time with, say, a set of sliders or numeric fields. It would be fairly simple to implement fields to alter whatever values you're determining (scale, speed, etc) during run-time which gives you immediate feedback. For placement, you could use either fields or manual placement with click-dragging (which might be slightly harder to implement, but much more intuitive).

This gives you complete control without compiling and running the code for every small fraction of a change. When you finally arrive at a look and feel with which you're happy, use those values in your list of constants. If this is too daunting because of the number of variables you're editing (say, numerous sprite locations in numerous levels), you would want to implement it in a level editor, I imagine, with the same functionality of manual adjustment but with the result of creating and storing the data adjusted.

Answer 2

An idea: I would think a camera for the front layer is enough. Placing sprites a distance away from that on the z plane, and lerping the distance gives you a fraction on which to move that back layer.

For example, an object distance 10 from the front camera moves 1/10 in the background layer. An object of distance 2, would move 1/2 in its respective layer, etc.