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a physics library for jMonkeyEngine
/*
* Copyright (c) 2023-2024 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.bullet.collision.shapes;
import com.jme3.export.InputCapsule;
import com.jme3.export.JmeExporter;
import com.jme3.export.JmeImporter;
import com.jme3.export.OutputCapsule;
import com.jme3.math.Vector3f;
import com.jme3.util.clone.Cloner;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import jme3utilities.Validate;
import jme3utilities.math.MyVector3f;
/**
* A convex collision shape to represent the Minkowki sum of 2 convex shapes,
* based on Bullet's {@code btMinkowskiSumShape}.
*
* @author Stephen Gold [email protected]
*/
public class MinkowskiSum extends ConvexShape {
// *************************************************************************
// constants and loggers
/**
* message logger for this class
*/
final public static Logger logger2
= Logger.getLogger(MinkowskiSum.class.getName());
/**
* field names for serialization
*/
final private static String tagShapeA = "shapeA";
final private static String tagShapeB = "shapeB";
// *************************************************************************
// fields
/**
* first shape on which this shape is based
*/
private ConvexShape shapeA;
/**
* 2nd shape on which this shape is based
*/
private ConvexShape shapeB;
// *************************************************************************
// constructors
/**
* No-argument constructor needed by SavableClassUtil.
*/
protected MinkowskiSum() {
}
/**
* Instantiate the Minkowki sum of the specified shapes.
*
* @param shapeA the first base shape (not null, convex, alias created)
* @param shapeB the 2nd base shape (not null, convex, alias created)
*/
public MinkowskiSum(ConvexShape shapeA, ConvexShape shapeB) {
Validate.nonNull(shapeA, "shape A");
Validate.nonNull(shapeA, "shape B");
this.shapeA = shapeA;
this.shapeB = shapeB;
createShape();
}
// *************************************************************************
// new methods exposed
/**
* Access the first base shape.
*
* @return the pre-existing shape (not null)
*/
public ConvexShape getShapeA() {
assert shapeA != null;
return shapeA;
}
/**
* Access the 2nd base shape.
*
* @return the pre-existing shape (not null)
*/
public ConvexShape getShapeB() {
assert shapeB != null;
return shapeB;
}
// *************************************************************************
// ConvexShape methods
/**
* Test whether the specified scale factors can be applied to this shape.
* For MinkowskiSum shapes, scaling must be unity.
*
* @param scale the desired scale factor for each local axis (may be null,
* unaffected)
* @return true if applicable, otherwise false
*/
@Override
public boolean canScale(Vector3f scale) {
boolean canScale = super.canScale(scale)
&& MyVector3f.isScaleIdentity(scale);
return canScale;
}
/**
* Callback from {@link com.jme3.util.clone.Cloner} to convert this
* shallow-cloned shape into a deep-cloned one, using the specified Cloner
* and original to resolve copied fields.
*
* @param cloner the Cloner that's cloning this shape (not null)
* @param original the instance from which this shape was shallow-cloned
* (not null, unaffected)
*/
@Override
public void cloneFields(Cloner cloner, Object original) {
super.cloneFields(cloner, original);
this.shapeA = cloner.clone(shapeA);
this.shapeB = cloner.clone(shapeB);
createShape();
copyShapeProperties((MinkowskiSum) original);
}
/**
* Return the collision margin of this shape.
*
* @return the margin thickness (in physics-space units, ≥0)
*/
@Override
public float getMargin() {
this.margin = shapeA.nativeMargin() + shapeB.nativeMargin();
float result = super.getMargin();
return result;
}
/**
* De-serialize the shape from the specified importer, for example when
* loading from a J3O file.
*
* @param importer (not null)
* @throws IOException from the importer
*/
@Override
public void read(JmeImporter importer) throws IOException {
super.read(importer);
InputCapsule capsule = importer.getCapsule(this);
this.shapeA = (ConvexShape) capsule.readSavable(tagShapeA, null);
this.shapeB = (ConvexShape) capsule.readSavable(tagShapeB, null);
createShape();
readShapeProperties(capsule);
}
/**
* Alter the collision margin of this shape. This feature is disabled for
* MinkowskiSum shapes. The margin of a MinkowskiSum is simply the sum of
* the (native) margins of the base shapes.
*
* @param margin the desired margin thickness (in physics-space units)
*/
@Override
public void setMargin(float margin) {
logger2.log(Level.WARNING,
"Cannot directly alter the margin of a MinkowskiSum");
}
/**
* Serialize this shape to the specified exporter, for example when saving
* to a J3O file.
*
* @param exporter (not null)
* @throws IOException from the exporter
*/
@Override
public void write(JmeExporter exporter) throws IOException {
super.write(exporter);
OutputCapsule capsule = exporter.getCapsule(this);
capsule.write(shapeA, tagShapeA, null);
capsule.write(shapeB, tagShapeB, null);
}
// *************************************************************************
// Java private methods
/**
* Instantiate a {@code btMinkowskiSumShape}.
*/
private void createShape() {
long shapeAId = shapeA.nativeId();
long shapeBId = shapeB.nativeId();
long shapeId = createShape(shapeAId, shapeBId);
setNativeId(shapeId);
setContactFilterEnabled(enableContactFilter);
setScale(scale);
this.margin = shapeA.getMargin() + shapeB.getMargin();
}
// *************************************************************************
// native private methods
native private static long createShape(long shapeAId, long shapeBId);
}
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