323 lines
14 KiB
C#
323 lines
14 KiB
C#
using UnityEngine;
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public class AIHovercarController : MonoBehaviour
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{
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[Header("Hover Settings")]
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public float hoverHeight = 3.0f;
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public float positionAdjustmentSpeed = 10.0f;
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public float raycastDistance = 10.0f;
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public LayerMask terrainLayer;
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[Header("Movement Settings")]
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public float movementSpeed = 10.0f; // Max speed
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public float acceleration = 5.0f; // How quickly to accelerate
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public float deceleration = 7.0f; // How quickly to decelerate
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public float rotationSpeed = 100.0f;
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[Header("Checkpoint Navigation")]
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[Tooltip("Ordered list of checkpoints for the AI to follow.")]
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public Transform[] checkpoints;
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[Tooltip("Distance from a checkpoint at which the AI switches to the next one.")]
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public float checkpointThreshold = 5.0f;
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private int currentCheckpointIndex = 0;
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[Header("Random Steering Settings")]
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[Tooltip("Probability per second that a random steering offset is applied (0 = never, 1 = every second on average).")]
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public float randomSteeringProbability = 0.2f;
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[Tooltip("Maximum random steering offset added (in normalized input units; e.g., 0.2 means up to ±20% extra steering).")]
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public float randomSteeringMaxOffset = 0.2f;
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[Header("Slowdown Settings")]
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[Tooltip("Distance before a checkpoint at which the AI begins to slow down.")]
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public float slowdownDistance = 10f;
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[Tooltip("Strength of the slowdown (0 = no slowdown, 1 = full slowdown to minimum throttle at the checkpoint).")]
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public float slowdownStrength = 0.5f;
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[Header("Reset Settings")]
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[Tooltip("Time (in seconds) without track contact before resetting the vehicle.")]
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public float timeBeforeReset = 3.0f;
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[Header("Track Orientation Settings")]
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[Tooltip("Distance to search downward for track (used to align the vehicle’s bottom).")]
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public float trackRaycastDistance = 10.0f;
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[Tooltip("Tag used on the track geometry.")]
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public string trackTag = "Track";
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[Header("Avoidance Settings")]
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[Tooltip("Radius within which the AI will try to avoid other racers.")]
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public float avoidanceRadius = 5.0f;
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[Tooltip("Strength of the steering adjustment to avoid collisions.")]
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public float avoidanceSteeringStrength = 0.5f;
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[Tooltip("Throttle multiplier applied when avoiding other racers (0 to 1, where lower means more slowdown).")]
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public float avoidanceSlowdownMultiplier = 0.5f;
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[Tooltip("Tag used to identify other racers for avoidance.")]
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public string racerTag = "Racer";
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private float currentSpeed = 0.0f;
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private Rigidbody rb;
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// Timer for lost ground/track contact
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private float noContactTimer = 0.0f;
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// Flag indicating if the hover raycast hit the terrain/track this physics frame
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private bool groundContact = false;
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void Start()
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{
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rb = GetComponent<Rigidbody>();
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rb.useGravity = false;
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}
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void FixedUpdate()
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{
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HandleHovering();
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HandleMovement();
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// If no ground/track contact is detected, count up the timer.
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if (!groundContact)
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{
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noContactTimer += Time.fixedDeltaTime;
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if (noContactTimer >= timeBeforeReset)
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{
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ResetToCheckpoint();
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noContactTimer = 0.0f; // Reset timer after repositioning.
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}
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}
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else
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{
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// Reset the timer when ground/track contact is re-established.
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noContactTimer = 0.0f;
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}
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}
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/// <summary>
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/// Hover logic: cast a ray downward, interpolate the hit point and normal on the terrain,
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/// and adjust the vehicle's position and rotation so it hovers along the track.
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/// Also sets the groundContact flag for reset timing.
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/// </summary>
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void HandleHovering()
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{
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RaycastHit hit;
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Vector3 rayOrigin = transform.position;
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if (Physics.Raycast(rayOrigin, -transform.up, out hit, raycastDistance, terrainLayer))
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{
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groundContact = true;
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Mesh mesh = hit.collider.GetComponent<MeshFilter>().mesh;
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int triangleIndex = hit.triangleIndex;
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int vertex1Index = mesh.triangles[triangleIndex * 3 + 0];
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int vertex2Index = mesh.triangles[triangleIndex * 3 + 1];
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int vertex3Index = mesh.triangles[triangleIndex * 3 + 2];
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Vector3 worldVertex1 = hit.collider.transform.TransformPoint(mesh.vertices[vertex1Index]);
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Vector3 worldVertex2 = hit.collider.transform.TransformPoint(mesh.vertices[vertex2Index]);
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Vector3 worldVertex3 = hit.collider.transform.TransformPoint(mesh.vertices[vertex3Index]);
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Vector3 interpolatedPoint = worldVertex1 * hit.barycentricCoordinate.x +
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worldVertex2 * hit.barycentricCoordinate.y +
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worldVertex3 * hit.barycentricCoordinate.z;
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Vector3 localNormal1 = mesh.normals[vertex1Index];
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Vector3 localNormal2 = mesh.normals[vertex2Index];
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Vector3 localNormal3 = mesh.normals[vertex3Index];
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Vector3 worldNormal1 = hit.collider.transform.TransformDirection(localNormal1);
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Vector3 worldNormal2 = hit.collider.transform.TransformDirection(localNormal2);
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Vector3 worldNormal3 = hit.collider.transform.TransformDirection(localNormal3);
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Vector3 interpolatedNormal = worldNormal1 * hit.barycentricCoordinate.x +
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worldNormal2 * hit.barycentricCoordinate.y +
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worldNormal3 * hit.barycentricCoordinate.z;
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interpolatedNormal.Normalize();
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Vector3 targetPosition = interpolatedPoint + interpolatedNormal * hoverHeight;
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transform.position = Vector3.Lerp(transform.position, targetPosition, Time.fixedDeltaTime * positionAdjustmentSpeed);
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Quaternion targetRotation = Quaternion.FromToRotation(transform.up, interpolatedNormal) * transform.rotation;
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rb.rotation = Quaternion.Slerp(rb.rotation, targetRotation, Time.fixedDeltaTime * 5.0f);
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}
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else
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{
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groundContact = false;
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}
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}
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/// <summary>
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/// Simulates input by computing throttle and steering based on the AI's orientation relative to the next checkpoint.
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/// New additions:
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/// - Random steering offset.
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/// - Throttle reduction when turning sharply and when approaching a checkpoint.
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/// - Avoidance: steer away from and slow down for nearby racers.
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/// </summary>
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void HandleMovement()
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{
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// Default simulated inputs.
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float verticalInput = 1f; // full throttle by default
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float horizontalInput = 0f;
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if (checkpoints != null && checkpoints.Length > 0)
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{
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Transform targetCheckpoint = checkpoints[currentCheckpointIndex];
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Vector3 toCheckpoint = targetCheckpoint.position - transform.position;
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float distanceToCheckpoint = toCheckpoint.magnitude;
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Vector3 toCheckpointNormalized = toCheckpoint.normalized;
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// If the target checkpoint is behind the vehicle, switch to the next one immediately.
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if (Vector3.Dot(transform.forward, toCheckpointNormalized) < 0)
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{
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currentCheckpointIndex = (currentCheckpointIndex + 1) % checkpoints.Length;
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}
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else
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{
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// Compute steering input based on the angle between the vehicle's forward and the direction to the checkpoint.
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Vector3 projectedForward = Vector3.ProjectOnPlane(transform.forward, transform.up).normalized;
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Vector3 projectedTarget = Vector3.ProjectOnPlane(toCheckpointNormalized, transform.up).normalized;
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float angle = Vector3.SignedAngle(projectedForward, projectedTarget, transform.up);
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horizontalInput = Mathf.Clamp(angle / 45f, -1f, 1f);
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// Add a random steering offset occasionally.
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if (Random.value < randomSteeringProbability * Time.fixedDeltaTime)
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{
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float randomOffset = Random.Range(-randomSteeringMaxOffset, randomSteeringMaxOffset);
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horizontalInput += randomOffset;
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horizontalInput = Mathf.Clamp(horizontalInput, -1f, 1f);
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}
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// Reduce throttle when turning sharply.
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verticalInput = Mathf.Clamp(1f - (Mathf.Abs(horizontalInput) * 0.5f), 0f, 1f);
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// Additional slowdown when approaching a checkpoint.
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if (distanceToCheckpoint < slowdownDistance)
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{
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float slowdownFactor = Mathf.Lerp(1 - slowdownStrength, 1f, distanceToCheckpoint / slowdownDistance);
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verticalInput *= slowdownFactor;
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}
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// Switch to the next checkpoint when close enough.
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if (distanceToCheckpoint < checkpointThreshold)
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{
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currentCheckpointIndex = (currentCheckpointIndex + 1) % checkpoints.Length;
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}
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}
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}
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// --- Avoidance Logic ---
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// Look for nearby racers and, if any are detected, adjust steering and throttle.
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Collider[] nearbyColliders = Physics.OverlapSphere(transform.position, avoidanceRadius);
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Vector3 avoidanceVector = Vector3.zero;
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int avoidanceCount = 0;
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foreach (Collider col in nearbyColliders)
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{
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if (col.gameObject != gameObject && col.CompareTag(racerTag))
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{
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Vector3 diff = transform.position - col.transform.position;
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if (diff.magnitude > 0)
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{
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// Closer objects contribute more.
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avoidanceVector += diff.normalized / diff.magnitude;
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avoidanceCount++;
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}
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}
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}
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if (avoidanceCount > 0)
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{
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avoidanceVector /= avoidanceCount;
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// Project onto the horizontal plane.
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avoidanceVector = Vector3.ProjectOnPlane(avoidanceVector, transform.up).normalized;
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// Determine steering adjustment from avoidance.
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float avoidanceAngle = Vector3.SignedAngle(transform.forward, avoidanceVector, transform.up);
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float avoidanceInput = Mathf.Clamp(avoidanceAngle / 45f, -1f, 1f) * avoidanceSteeringStrength;
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horizontalInput += avoidanceInput;
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horizontalInput = Mathf.Clamp(horizontalInput, -1f, 1f);
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// Slow down throttle when avoiding.
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verticalInput *= avoidanceSlowdownMultiplier;
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}
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// --- End Avoidance Logic ---
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// Apply movement: accelerate/decelerate toward the target speed, then update velocity and angular velocity.
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float targetSpeed = verticalInput * movementSpeed;
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if (verticalInput != 0)
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{
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currentSpeed = Mathf.Lerp(currentSpeed, targetSpeed, Time.fixedDeltaTime * acceleration);
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}
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else
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{
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currentSpeed = Mathf.Lerp(currentSpeed, 0, Time.fixedDeltaTime * deceleration);
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}
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rb.linearVelocity = transform.forward * currentSpeed;
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float turn = horizontalInput * rotationSpeed;
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rb.angularVelocity = transform.up * turn * Mathf.Deg2Rad;
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}
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/// <summary>
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/// Resets the AI's position to the last checkpoint it passed and reorients it so that:
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/// - Its front faces toward the nearest (other) checkpoint.
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/// - Its bottom is aligned with the nearby track surface (determined via a raycast and track tag).
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/// </summary>
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void ResetToCheckpoint()
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{
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if (checkpoints == null || checkpoints.Length == 0)
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{
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Debug.LogWarning("No checkpoints assigned in the Inspector.");
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return;
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}
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// Determine the last checkpoint passed.
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int lastCheckpointIndex = currentCheckpointIndex - 1;
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if (lastCheckpointIndex < 0)
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{
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lastCheckpointIndex = checkpoints.Length - 1;
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}
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Transform lastCheckpoint = checkpoints[lastCheckpointIndex];
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// Find the nearest other checkpoint (to set the forward direction).
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Transform nearestOther = null;
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float nearestDistance = Mathf.Infinity;
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foreach (Transform cp in checkpoints)
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{
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if (cp == lastCheckpoint)
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continue;
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float d = Vector3.Distance(lastCheckpoint.position, cp.position);
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if (d < nearestDistance)
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{
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nearestDistance = d;
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nearestOther = cp;
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}
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}
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// Determine desired forward direction.
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Vector3 desiredForward = (nearestOther != null)
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? (nearestOther.position - lastCheckpoint.position).normalized
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: transform.forward;
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// Determine the track’s surface normal to align the vehicle’s bottom.
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// Raycast downward from a point just above the checkpoint.
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Vector3 desiredUp = Vector3.up; // Fallback
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RaycastHit hit;
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Vector3 rayOrigin = lastCheckpoint.position + Vector3.up * 1.0f;
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if (Physics.Raycast(rayOrigin, -Vector3.up, out hit, trackRaycastDistance))
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{
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if (hit.collider.CompareTag(trackTag))
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{
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// Use the inverted hit normal so the vehicle’s bottom (–transform.up) is flush with the track.
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desiredUp = -hit.normal;
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}
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}
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// Adjust desired forward so that it is perpendicular to desired up.
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desiredForward = Vector3.ProjectOnPlane(desiredForward, desiredUp).normalized;
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Quaternion desiredRotation = Quaternion.LookRotation(desiredForward, desiredUp);
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// Reset position and orientation.
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transform.position = lastCheckpoint.position;
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transform.rotation = desiredRotation;
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// Clear any existing motion.
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rb.linearVelocity = Vector3.zero;
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rb.angularVelocity = Vector3.zero;
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Debug.Log("AI reset to checkpoint: " + lastCheckpoint.name +
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(nearestOther != null ? " with front facing: " + nearestOther.name : ""));
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}
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}
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