Merge pull request jMonkeyEngine#2022 from Electrostat-Lab/blendspace-javadocs

com.jme3.anim.tween.action.BlendSpace: basic javadoc

Author: yaRnMcDonuts

jme3-core/src/main/java/com/jme3/anim/tween/action/BlendSpace.java

@@ -1,10 +1,95 @@
+/*
+ * Copyright (c) 2009-2025 jMonkeyEngine
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of 'jMonkeyEngine' nor the names of its contributors
+ *   may be used to endorse or promote products derived from this software
+ *   without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
 package com.jme3.anim.tween.action;
 
+/**
+ * A provider interface which provides a value {@link BlendSpace#getWeight()} to control the blending between 2 successive actions in a {@link BlendAction}.
+ * The blending weight is a read-only value, and it can be manipulated using the arbitrary value {@link BlendSpace#setValue(float)} during the application runtime.
+ * 
+ * <p>
+ * Notes about the blending action and its relations with the blending weight:
+ * <ul>
+ * <li> Blending is the action of mixing between 2 successive animation {@link BlendableAction}s by interpolating their transforms and 
+ * then applying the result on the assigned {@link HasLocalTransform} object, the {@link BlendSpace} provides this blending action with a blend weight value. </li>
+ * <li> The blend weight is the value for the interpolation for the target transforms. </li>
+ * <li> The blend weight value must be in this interval [0, 1]. </li>
+ * </ul>
+ * </p>
+ * 
+ * <p>
+ * Different blending weight case scenarios managed by {@link BlendAction} internally:
+ * <ul>
+ * <li> In case of (0 < Blending weight < 1), the blending is executed each update among 2 actions, the first action will use 
+ * a blend value of 1 and the second action will use the blend space weight as a value for the interpolation. </li>
+ * <li> In case of (Blending weight = 0), the blending hasn't started yet, only the first action will be interpolated at (weight = 1). </li>
+ * <li> In case of (Blending weight = 1), the blending is finished and only the second action will continue to run at (weight = 1). </li>
+ * </ul>
+ * </p>
+ * 
+ * <p>
+ * Notes about the blending weight value:
+ * <ul>
+ * <li> Negative values and values greater than 1 aren't allowed (i.e., extrapolations aren't allowed). </li>
+ * <li> For more details, see {@link BlendAction#doInterpolate(double)} and {@link BlendAction#collectTransform(HasLocalTransform, Transform, float, BlendableAction)}. </li>
+ * </ul>
+ * </p> 
+ *
+ * Created by Nehon.
+ * @see LinearBlendSpace an example of blendspace implementation
+ */
 public interface BlendSpace {
 
+    /**
+     * Adjusts the target blend action instance that will utilize the blend weight value provided by this blend-space implementation.
+     * 
+     * @param action the blend action instance that will utilize this blend-space (not null).
+     */
     public void setBlendAction(BlendAction action);
 
+    /**
+     * Provides the blend weight value to the assigned {@link BlendAction} instance,
+     * this value will be used for interpolating a collection of actions' transformations (i.e., keyframes).
+     * 
+     * @return the blending weight value in the range from 0 to 1, 
+     *         negative values and values above 1 aren't allowed.
+     * @see LinearBlendSpace#getWeight()
+     */
     public float getWeight();
 
+    /**
+     * An arbitrary value used for adjusting the blending weight value.
+     * 
+     * @param value the value in floats.
+     * @see LinearBlendSpace#setValue(float)
+     */
     public void setValue(float value);
 }