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JBox2D 2.0.1 » org » jbox2d » common » Settings.java
/*
 * JBox2D - A Java Port of Erin Catto's Box2D
 * 
 * JBox2D homepage: http://jbox2d.sourceforge.net/ 
 * Box2D homepage: http://www.box2d.org
 * 
 * This software is provided 'as-is', without any express or implied
 * warranty.  In no event will the authors be held liable for any damages
 * arising from the use of this software.
 * 
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 * 
 * 1. The origin of this software must not be misrepresented; you must not
 * claim that you wrote the original software. If you use this software
 * in a product, an acknowledgment in the product documentation would be
 * appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 * misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 */

package org.jbox2d.common;

//Updated to rev. 142 of b2Settings.cpp/.h


/** Global tuning constants based on MKS units and various integer maximums (vertices per shape, pairs, etc.). */
public class Settings {

    /** A "close to zero" float epsilon value for use */
    public static final float EPSILON = 1.1920928955078125E-7f;

    /** Pi. */
    public static final float pi = (float) Math.PI;

    // Define your unit system here. The default system is
    // meters-kilograms-seconds. For the tuning to work well,
    // your dynamic objects should be bigger than a pebble and smaller
    // than a house.
    //
    // Use of these settings has been deprecated - they do not even
    // exist anymore in the C++ version of the engine, and future support
    // is unlikely.
    public static final float lengthUnitsPerMeter = 1.0f;
    public static final float massUnitsPerKilogram = 1.0f;
    public static final float timeUnitsPerSecond = 1.0f;

    // Collision
    
    public static final int maxManifoldPoints = 2;
    public static final int maxShapesPerBody = 64;
    public static final int maxPolygonVertices = 8;

    /** Must be a power of two. */
    public static final int maxProxies = 2048;
    /** Must be a power of two. */
    public static final int maxPairs = 8 * maxProxies;
    
    // Dynamics

    /**
     * A small length used as a collision and constraint tolerance. Usually it is
     * chosen to be numerically significant, but visually insignificant.
     */
    public static final float linearSlop = 0.005f * lengthUnitsPerMeter; // 0.5 cm

    /**
     * A small angle used as a collision and constraint tolerance. Usually it is
     * chosen to be numerically significant, but visually insignificant.
   */
    public static final float angularSlop = 2.0f / 180.0f * pi; // 2 degrees

    /**
   * A velocity threshold for elastic collisions. Any collision with a relative linear
     * velocity below this threshold will be treated as inelastic.
     */
    public static final float velocityThreshold = 1.0f * lengthUnitsPerMeter
            / timeUnitsPerSecond; // 1 m/s

    /**
     * The maximum linear position correction used when solving constraints. This helps to
     * prevent overshoot.
     */
    public static final float maxLinearCorrection = 0.2f * lengthUnitsPerMeter; // 20 cm

    /**
     * The maximum angular position correction used when solving constraints. This helps to
     * prevent overshoot.
     */
    public static final float maxAngularCorrection = 8.0f / 180.0f * pi; // 8 degrees

    /**
     * This scale factor controls how fast overlap is resolved. Ideally this would be 1 so
     * that overlap is removed in one time step. However using values close to 1 often lead
     * to overshoot.
     */
    public static final float contactBaumgarte = 0.2f;

    /** The time that a body must be still before it will go to sleep. */
    public static final float timeToSleep = 0.5f * timeUnitsPerSecond; // half a second

    /** A body cannot sleep if its linear velocity is above this tolerance. */
    public static final float linearSleepTolerance = 0.01f
            * lengthUnitsPerMeter / timeUnitsPerSecond; // 1 cm/s

    /** A body cannot sleep if its angular velocity is above this tolerance. */
    public static final float angularSleepTolerance = 2.0f / 180.0f / timeUnitsPerSecond;
    
    /**
     * Continuous collision detection (CCD) works with core, shrunken shapes. This is the
     * amount by which shapes are automatically shrunk to work with CCD. This must be
     * larger than b2_linearSlop.
     */
    public static final float toiSlop = 8.0f * linearSlop;
    
    /**
     * The maximum linear velocity of a body. This limit is very large and is used
     * to prevent numerical problems. You shouldn't need to adjust this.
     */
    public static final float maxLinearVelocity = 200.0f;
    public static final float maxLinearVelocitySquared = maxLinearVelocity * maxLinearVelocity;

    /**
     * The maximum angular velocity of a body. This limit is very large and is used
     * to prevent numerical problems. You shouldn't need to adjust this.
     */
    public static final float maxAngularVelocity = 250.0f;
    public static final float maxAngularVelocitySquared = maxAngularVelocity * maxAngularVelocity;

    /** Maximum number of contacts to be handled to solve a TOI island. */
    public static int maxTOIContactsPerIsland = 32;


}
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