Shown above is a depiction of the mechanic I re-created. I chose to re-create the "parachute" mechanic from "Mariokart 8 Deluxe." "Mix N Jam" on YouTube inspired me to embark on this project. The channel link is here: (https://www.youtube.com/watch?v=Ki-tWT50cEQ&t=85s). The kart 3D model is here: (https://sketchfab.com/3d-models/kart-222d072cbd0f43eaa16a9e51e1f5078d).
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Shown below is a demonstration of my completed mechanic in Unity.
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The first hurdle I faced was developing the "base kart" controls, or the controls that dictate the kart's movement when on the ground. The player is actually controlling a sphere collider with a rigidbody, and the kart model is merely copying the position of the sphere. A demonstration of the rolling sphere collider in action is shown below:
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Shown below is the structure for the aforementioned "base kart" behavior. First I needed everything regarding the kart to follow the "roller ball" collider. I defined "Fire1" to my left mouse in my unity settings, so this is the command for acceleration. I then use an if-statement to set the kart's speed equal to it's acceleration, and to make sure my exhaust particle effect is emitting.
Given that the "Horizontal" axis is defined by the A and D keys, I use an if-statement that determines if the player is trying to turn, and if true quickly initialize the values for the turn rate, and then run the Steer(dir, amount) function, which is defined later in MasterSteeringInitAndCall().
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Shown below is the code behind the FollowCollider() call, and the MasterSteeringInitandCall() commands.
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Shown above, SetKartOrientation() is the call for the function that runs the logic for the kart's perceived acceleration. InitBaseKartControllerGravity() is the call for the function that dictates how gravity should affect the kart while it is on the ground. BaseSteeringInit() is the call for one of the most complex functions, and this function uses a raycast from the "roller ball" to the ground to ensure the kart rotates on the ground appropriately. Also depicted above is the "master" Steer(dir, amount) function that is called from MasterSteeringInitAndCall(), inside of Update().
Shown below is the logic for SetKartOrientation(), InitBaseKartControllerGravity(), and BaseSteeringInit().
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The next hurdle in development I faced was getting the kart to respond to it's environment. When faced with an item such as a ramp, the kart would not rotate according to it's new slanted ground, and would appear to scrape into the ramp, then translate upward despite the BaseSteeringInit() function. The solution to this was found by dissecting further the "Mix N Jam" video, and using trial and error to order my groups of gameObjects until I got the desired effect. The order in the hierarchy that worked is shown below:
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The next hurdle I faced was by far the most challenging, and this was engineering the actual parachute mechanic so that when the Space bar is pressed the player is yielded with an experience that mimics the reference capture.
This means that I would have to override my "base kart" controller script's steering, ensure that there is a noticeable slow decent to the ground, and ensure that the kart pivots in the air according to player input.
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Shown below is the script that controls the pivoting of the kart when airborne. In effect the architecture for both the X and Y rotation of the kart is simply defining an axis to manipulate, moving the axis by a set value, converting the axis's float (tiltAngle) to a Quaternion, and then smoothing the animation out over time.
Equally important, inside of the GetButton() if-statement is the command to null out the base kart controller's aforementioned Steer() master call, which effectively serves as an override to the entire "base kart" controller script.
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Next, I needed to make the kart actually move in the air according to the player's input. Shown below is my script for that purpose.
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I am simply adding a pivot impulse force to the "roller ball" depending on the player's "Horizontal axis" input, while the space bar is held. It is interesting to note that the "ForceMode.Impulse" command gave me the results I needed to replicate the source material. The results I obtained at this point are shown below:
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The kart had far too little gravity acting upon it. To fix this I added the following script:
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I am simply passing in the Rigidbody of the "roller ball," then forcing it down over time when the Space bar is held.
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Shown below is my sound engineering to further add life to the kart:
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I was able to obtain from (https://www.sounds-resource.com/wii_u/mariokart8/) the exact engine audio from Mariokart 8, then I scripted the engine audio to be at a lower pitch for a split-second, when the command to accelerate is pressed. The script makes the engine pitch get higher until a certain point, which will be calibrated to the top speed of the kart. My finished audio script is shown above.
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The final step of the endeavor was using the particle system to create the small vapor vortexes on either end of the parachute, and setting the parachute active when the space bar is pressed. I obtained the 3D model of the parachute from: (https://sketchfab.com/3d-models/parachute-b9a64468b62e4ef287a4b2e40ad96408), and the parachute is set active and deactivated based off the player's Space bar input; which is the master command to use the parachute functionality.
It is interesting to note that the particle systems are actually just rendering "trails," and there are no conventional particles being used.
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Top-Down Space Shooter
Click the image above to go to "Top Down Space Shooter."
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