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/*
Copyright (c) 2019-2023, Stephen Gold
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 the copyright holder 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 HOLDER 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 jme3utilities.mesh;
import com.jme3.math.FastMath;
import com.jme3.scene.Mesh;
import com.jme3.scene.VertexBuffer;
import com.jme3.util.BufferUtils;
import java.nio.FloatBuffer;
import java.util.logging.Logger;
import jme3utilities.MyMesh;
import jme3utilities.Validate;
/**
* A 3-D, static, Triangles-mode Mesh (without indices or texture coordinates)
* that renders a tetrahedron. (An tetrahedron has 4 triangular faces.)
*
* @author Stephen Gold [email protected]
* @see jme3utilities.mesh.Icosahedron
*/
public class Tetrahedron extends Mesh {
// *************************************************************************
// constants and loggers
/**
* number of axes in a vector
*/
final private static int numAxes = 3;
/**
* message logger for this class
*/
final public static Logger logger
= Logger.getLogger(Tetrahedron.class.getName());
// *************************************************************************
// constructors
/**
* No-argument constructor needed by SavableClassUtil.
*/
protected Tetrahedron() {
}
/**
* Instantiate a regular tetrahedron with the specified radius.
*
* The center is at (0,0,0). The Y axis bisects 2 edges. All triangles face
* outward.
*
* @param radius the desired distance of the vertices from the center (in
* mesh units, >0)
* @param generateNormals true → generate normals, false → no
* normals
*/
public Tetrahedron(float radius, boolean generateNormals) {
Validate.positive(radius, "radius");
float h = radius / FastMath.sqrt(3f);
FloatBuffer positionBuffer = BufferUtils.createFloatBuffer(
-h, +h, +h, // A
+h, +h, -h, // B
-h, -h, -h, // D
-h, +h, +h, // A
+h, -h, +h, // C
+h, +h, -h, // B
-h, +h, +h, // A
-h, -h, -h, // D
+h, -h, +h, // C
-h, -h, -h, // D
+h, +h, -h, // B
+h, -h, +h // C
);
setBuffer(VertexBuffer.Type.Position, numAxes, positionBuffer);
positionBuffer.clear();
if (generateNormals) {
MyMesh.generateFacetNormals(this);
}
updateBound();
setStatic();
}
}