January 26, 2021
Camera
2D Platformer Design
Title:
Mario Style Camera Follow Tutorial
By:
Press Start
Description:
Camera tutorial that follows similar to Mario for 2D platformers.
Overview
I got to implementing this tutorial into my 2D platformer project, which let me observe some of the pros and cons of this approach the way they created it. They created a direct following camera, which used a threshold to determine if the player is some distance from the center of the camera, and if so, starts to follow them as they move. I also created my own camera controller variation which moves in more
Camera Controller: Follow Camera (by Press Start)
This is the camera controller created in the tutorial linked above. The camera follows an object, generally the player, smoothly as they press against the borders of the camera threshold. The object must move some significant amount of distance before the camera moves. This keeps the camera from constantly moving, keeping more of the environment in a static frame longer.
There is an offset distance which is the distance from the edge of the camera that sets the bounds of the threshold box. When the follow object moves outside of this box, the camera begins to follow it. As long as the object continues to move out of the box, the camera will continue to keep following it.
Unity Orthographic Size
Orthographic Size: half the height in world units that the camera renders
The horizontal dimension rendered is solely determined by the screen ratio along with the height determined by orthographic size. Determining the size of a camera to fit objects vertically is very straightforward, as it is just half of the world units you would like to render. If you want to fit something horizontally however, you must include the screen ratio and use that as a multiplier (screen height / screen width) to convert the world width into an orthographic size value.
Issue: Stuttering
Originally the camera following gave a stuttering, glitchy effect while following the player at times, especially when jumping. I believe this is a result of changing the speed value set for the camera to match the player speed when it is large, since it uses the magnitude of the player’s velocity vector. This can change a lot very quickly, especially when jumping since this combines the x and y vector values of the player’s movement at that point.
Changing this speed check and set to solely the x-axis helped with consistency for most movement because most movement is horizontal. This however will most likely have a large impact if there is a lot of vertical movement since it will still be looking at the player’s velocity in the x to move the camera, regardless of their y velocity.
My Implementation of the FollowCamera Script with Modification
Alternate Camera Controller: Chunk Camera
Because of the stuttering effect I originally encountered, I tried making another type of camera controller that I thought may be a good option. I wanted to use a chunk movement approach where once the player reached the threshold of the current camera position, it would move the camera in that direction an entire chunk distance, centering the camera on the next location as opposed to directly moving with the player. The idea with this is that it keeps the camera movement more consistent, as well as showing the player much more of the next area they intend to move into more quickly.
I approached this by creating an IEnumerator named TransitionCamera that activates when the player hits a threshold. This begins a Lerp movement for the camera to the next designated chunk area, determined at Start based on the screen size and the threshold distance. A chunk distance is determined as: screen size – threshold distance. This centers the camera one full screen over, with an overlap from the previous screen equal to the threshold distance.
I also added a check to stop the coroutine if it was running and it was determined that it should start moving again to prevent weird whiplash effects if a player somehow was able to move back and forth between two screens very quickly. While mostly effective, this did have the negative resulting bug of slightly offsetting the camera completely over time because the TransitionCamera coroutine would be stopped prematurely and start moving to a new location solely determined by the current location +/- the chunk distance.
Summary
The original FollowCamera camera controller had more issues than I anticipated, so making it clean and consistent will take significantly more work. The jitteriness of the original implementation is unusable, but the modification at least makes it decent to use as a base for now as long as most movement is horizontal.
The chunk camera modification is at least cleaner already, although it still needs a bit of tweaking to make something that does not get slowly offset over time. This however probably only works for specific games and cannot be used for every 2D game case. Having both of these options is nice moving forward and is easy to switch between.
via Blogger http://stevelilleyschool.blogspot.com/2021/01/2d-platformer-follow-camera-tutorial-by.html