com.badlogic.gdx.ai.steer.behaviors.Seek.java Source code

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Here is the source code for com.badlogic.gdx.ai.steer.behaviors.Seek.java

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/*******************************************************************************
 * Copyright 2011 See AUTHORS file.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/

package com.badlogic.gdx.ai.steer.behaviors;

import com.badlogic.gdx.ai.steer.Limiter;
import com.badlogic.gdx.ai.steer.Steerable;
import com.badlogic.gdx.ai.steer.SteeringAcceleration;
import com.badlogic.gdx.ai.steer.SteeringBehavior;
import com.badlogic.gdx.math.Vector;

/** {@code Seek} behavior moves the owner towards the target position. Given a target, this behavior calculates the linear steering
 * acceleration which will direct the agent towards the target as fast as possible.
 * 
 * @param <T> Type of vector, either 2D or 3D, implementing the {@link Vector} interface
 * 
 * @author davebaol */
public class Seek<T extends Vector<T>> extends SteeringBehavior<T> {

    /** The target to seek */
    protected Steerable<T> target;

    /** Creates a {@code Seek} behavior for the specified owner.
     * @param owner the owner of this behavior. */
    public Seek(Steerable<T> owner) {
        this(owner, null);
    }

    /** Creates a {@code Seek} behavior for the specified owner and target.
     * @param owner the owner of this behavior
     * @param target the target agent of this behavior. */
    public Seek(Steerable<T> owner, Steerable<T> target) {
        super(owner);
        this.target = target;
    }

    @Override
    protected SteeringAcceleration<T> calculateRealSteering(SteeringAcceleration<T> steering) {
        // Try to match the position of the character with the position of the target by calculating
        // the direction to the target and by moving toward it as fast as possible.
        steering.linear.set(target.getPosition()).sub(owner.getPosition()).nor()
                .scl(getActualLimiter().getMaxLinearAcceleration());

        // No angular acceleration
        steering.angular = 0;

        // Output steering acceleration
        return steering;
    }

    /** Returns the target to seek. */
    public Steerable<T> getTarget() {
        return target;
    }

    /** Sets the target to seek.
     * @return this behavior for chaining. */
    public Seek<T> setTarget(Steerable<T> target) {
        this.target = target;
        return this;
    }

    //
    // Setters overridden in order to fix the correct return type for chaining
    //

    @Override
    public Seek<T> setOwner(Steerable<T> owner) {
        this.owner = owner;
        return this;
    }

    @Override
    public Seek<T> setEnabled(boolean enabled) {
        this.enabled = enabled;
        return this;
    }

    /** Sets the limiter of this steering behavior. The given limiter must at least take care of the maximum linear acceleration.
     * @return this behavior for chaining. */
    @Override
    public Seek<T> setLimiter(Limiter limiter) {
        this.limiter = limiter;
        return this;
    }

}