Projectile Toolkit > Targeting and Prediction Version 3.1

Introduction

Targeting and Prediction describes the static library Projectile. It contains static methods to solve targeting (aka ballistics) problems and to predict various projectile data.

API example use cases

Targeting and Prediction API provides various algorithms to meet the needs of different scenarios, here are some example use cases:

Targeting

Prediction

How to use

Targeting

To launch a projectile to hit a target:

1. Add a Collider and a Rigidbody to your prefab if it doesn't have one (you can set Interpolate to Interpolate and set Collision Detection to Continuous Dynamic to get the best result),

2. In your code, instantiate the prefab,

3. Call one of the targeting algorithms to calculate the launch velocity, and apply it using AddForce(...).

The targeting algorithms are all static methods so the integration is very flexible.

Example code

Take VelocityByTime(...) for example, if you want AI units to accurately striking moving objects:

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[SerializeField] Rigidbody projectilePrefab;
[SerializeField] Transform launchPoint;
[SerializeField] float timeOfFlight;
...
// In your own method:
var myRigid = Instantiate(projectilePrefab, launchPoint, launchPoint.rotation);
var v = Projectile.VelocityByTime(myRigid.position, predictedPos, timeOfFlight);
myRigid.AddForce(v, ForceMode.VelocityChange);

View Defender.cs for the whole implementation of this (how to calculate predictedPos, etc.).

Additionally, you can add a SimpleExplosive component to your prefab, it handles collision events, explosion VFX, explosion force, and damage. Add the following logic below the above lines to make it work properly (for the above example, targetPosition is predictedPos):

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myRigid.GetComponent<ProjectileBehaviour>().Launch(targetPosition);

For 2D

In 2D, everything is the same, except that Rigidbody2D does not have ForceMode2D.VelocityChange mode, so we use ForceMode2D.Impulse instead:

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myRigid2D.AddForce(myRigid2D.mass * v, ForceMode2D.Impulse);

Trajectory prediction

There are 3 approaches to do trajectory prediction, here is a table that compares their pros and cons:

How to use TrajectoryPredictor

1. Drag and drop the prefab "Trajectory Predictor.prefab" in folder "Blobcreate/Projectile Toolkit/Prefabs" into your scene,

2. In your script, add the following logic:

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[SerializeField] TrajectoryPredictor tp;
...
// Update() or your own method
void Update()
{
    // Call Render to update the positions of the line.
    tp.Render(launchPosition, launchVelocity, distanceOrEnd);
}

Or if you want to predict the trajectory of a moving rigidbody:

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tp.Render(myRigid.transform.position, myRigid.velocity, distanceOrEnd);

Explore the demos

Online

Click here to play the online version (WebGL).

In editor

You can explore the demos under the folder "Blobcreate/Projectile Toolkit/Demos".

Some setup is required:

1. Materials

The materials are URP (Render Pipeline) materials. Make sure to test the scenes in a URP project.

2. Visual setup (optional)

If your project uses URP but there are rendering problems with demo scenes you can use "PTK-URP-HighQuality" render pipeline asset.

3. Set up layers and physics

Back up your layer settings and physics settings, and apply the layer preset "PTKLayers" and physics preset "PTKPhysics" under ".../Demos/Other Assets/Settings". Detailed steps:

1. (At the top right of Unity editor) select "Layers > Edit Layers...",

2. Click the second icon in the top right of the inspector,

3. Click "Save current to..." button to back up your current layer settings,

4. Click that second icon again and then choose "PTKLayers" in the pop up window.

In Unity 6 and above, in physics settings, the layer collision matrix should be manually set to the same as below. Also, set the Gravity to (0, -29.43, 0).

Relation

Which scene demonstrates which algorithm? The relation is shown in the table below:

For TrajectoryPredictor component, the demo scene is 02. For other features, you can find the corresponding demo scenes by their names.