1 files changed, 85 insertions, 0 deletions
diff --git a/engine/src/core/com/jme3/scene/control/AreaUtils.java b/engine/src/core/com/jme3/scene/control/AreaUtils.java
new file mode 100644
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+++ b/engine/src/core/com/jme3/scene/control/AreaUtils.java
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+/*
+ * Copyright (c) 2009-2010 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.scene.control;
+
+import com.jme3.bounding.BoundingBox;
+import com.jme3.bounding.BoundingSphere;
+import com.jme3.bounding.BoundingVolume;
+import com.jme3.math.FastMath;
+
+/**
+ * <code>AreaUtils</code> is used to calculate the area of various objects, such as bounding volumes.  These
+ * functions are very loose approximations.
+ * @author Joshua Slack
+ * @version $Id: AreaUtils.java 4131 2009-03-19 20:15:28Z blaine.dev $
+ */
+
+public class AreaUtils {
+
+  /**
+   * calcScreenArea -- in Pixels
+   * Aproximates the screen area of a bounding volume.  If the volume isn't a
+   * BoundingSphere, BoundingBox, or OrientedBoundingBox 0 is returned.
+   *
+   * @param bound The bounds to calculate the volume from.
+   * @param distance The distance from camera to object.
+   * @param screenWidth The width of the screen.
+   * @return The area in pixels on the screen of the bounding volume.
+   */
+  public static float calcScreenArea(BoundingVolume bound, float distance, float screenWidth) {
+      if (bound.getType() == BoundingVolume.Type.Sphere){
+          return calcScreenArea((BoundingSphere) bound, distance, screenWidth);
+      }else if (bound.getType() == BoundingVolume.Type.AABB){
+          return calcScreenArea((BoundingBox) bound, distance, screenWidth);
+      }
+      return 0.0f;
+  }
+
+  private static float calcScreenArea(BoundingSphere bound, float distance, float screenWidth) {
+    // Where is the center point and a radius point that lies in a plan parallel to the view plane?
+//    // Calc radius based on these two points and plug into circle area formula.
+//    Vector2f centerSP = null;
+//    Vector2f outerSP = null;
+//    float radiusSq = centerSP.subtract(outerSP).lengthSquared();
+      float radius = (bound.getRadius() * screenWidth) / (distance * 2);
+      return radius * radius * FastMath.PI;
+  }
+
+  private static float calcScreenArea(BoundingBox bound, float distance, float screenWidth) {
+      // Calc as if we are a BoundingSphere for now...
+      float radiusSquare = bound.getXExtent() * bound.getXExtent()
+                         + bound.getYExtent() * bound.getYExtent()
+                         + bound.getZExtent() * bound.getZExtent();
+      return ((radiusSquare * screenWidth * screenWidth) / (distance * distance * 4)) * FastMath.PI;
+  }
+}
+\ No newline at end of file