gov/nasa/worldwind/geom/ViewFrustum.java

   1 /*
   2 Copyright (C) 2001, 2006 United States Government as represented by
   3 the Administrator of the National Aeronautics and Space Administration.
   4 All Rights Reserved.
   5 */
   6 package gov.nasa.worldwind.geom;
   7
   8 import gov.nasa.worldwind.*;
   9
  10 import java.util.logging.Level;
  11
  12 /**
  13  * @author Paul Collins
  14  * @version $Id: ViewFrustum.java 1774 2007-05-08 01:03:37Z dcollins $
  15  */
  16 public class ViewFrustum
  17 {
  18     private final Frustum frustum;
  19     private final Matrix4 projection;
  20 //    private java.awt.geom.Rectangle2D nearRect;
  21 //    private java.awt.geom.Rectangle2D farRect;
  22
  23     public ViewFrustum(Matrix4 projectionMatrix)
  24     {
  25         if (projectionMatrix == null)
  26         {
  27             String message = WorldWind.retrieveErrMsg("nullValue.MatrixIsNull");
  28             WorldWind.logger().log(java.util.logging.Level.FINE, message);
  29             throw new IllegalArgumentException(message);
  30         }
  31
  32         double[] m = projectionMatrix.getEntries();
  33         // Extract the near clipping plane from the projection-matrix.
  34         double nearMag = Math.sqrt((m[3] + m[2]) * (m[3] + m[2]) + (m[7] + m[6]) * (m[7] + m[6])
  35             + (m[11] + m[10]) * (m[11] + m[10]));
  36         Plane nearPlane = new Plane((m[3] + m[2]) / nearMag, (m[7] + m[6]) / nearMag, (m[11] + m[10]) / nearMag,
  37             m[15] + m[14]);
  38         // Extract the far clipping plane from the projection-matrix.
  39         double farMag = Math.sqrt((m[3] - m[2]) * (m[3] - m[2]) + (m[7] - m[6]) * (m[7] - m[6])
  40             + (m[11] - m[10]) * (m[11] - m[10]));
  41         Plane farPlane = new Plane((m[3] - m[2]) / farMag, (m[7] - m[6]) / farMag, (m[11] - m[10]) / farMag,
  42             m[15] - m[14]);
  43         // Extract the left clipping plane from the projection-matrix.
  44         double leftMag = Math.sqrt((m[3] + m[0]) * (m[3] + m[0]) + (m[7] + m[4]) * (m[7] + m[4])
  45             + (m[11] + m[8]) * (m[11] + m[8]));
  46         Plane leftPlane = new Plane((m[3] + m[0]) / leftMag, (m[7] + m[4]) / leftMag, (m[11] + m[8]) / leftMag,
  47             m[15] + m[12]);
  48         // Extract the right clipping plane from the projection-matrix.
  49         double rightMag = Math.sqrt((m[3] - m[0]) * (m[3] - m[0]) + (m[7] - m[4]) * (m[7] - m[4])
  50             + (m[11] - m[8]) * (m[11] - m[8]));
  51         Plane rightPlane = new Plane((m[3] - m[0]) / rightMag, (m[7] - m[4]) / rightMag, (m[11] - m[8]) / rightMag,
  52             m[15] - m[12]);
  53         // Extract the bottom clipping plane from the projection-matrix.
  54         double bottomMag = Math.sqrt((m[3] + m[1]) * (m[3] + m[1]) + (m[7] + m[5]) * (m[7] + m[5])
  55             + (m[11] + m[9]) * (m[11] + m[9]));
  56         Plane bottomPlane = new Plane((m[3] + m[1]) / bottomMag, (m[7] + m[5]) / bottomMag, (m[11] + m[9]) / bottomMag,
  57             m[15] + m[13]);
  58         // Extract the top clipping plane from the projection-matrix.
  59         double topMag = Math.sqrt((m[3] - m[1]) * (m[3] - m[1]) + (m[7] - m[5]) * (m[7] - m[5])
  60             + (m[11] - m[9]) * (m[11] - m[9]));
  61         Plane topPlane = new Plane((m[3] - m[1]) / topMag, (m[7] - m[5]) / topMag, (m[11] - m[9]) / topMag,
  62             m[15] - m[13]);
  63         this.frustum = new Frustum(nearPlane, farPlane, leftPlane, rightPlane, bottomPlane, topPlane);
  64         this.projection = projectionMatrix;
  65     }
  66
  67     /**
  68      * Creates a <code>Frustum</code> from a horizontal field-of-view, viewport aspect ratio and distance to near and
  69      * far depth clipping planes. The near plane must be closer than the far plane, and both planes must be a positive
  70      * distance away.
  71      *
  72      * @param fieldOfView    horizontal field-of-view angle in the range (0, 180)
  73      * @param viewportWidth  the width of the viewport in screen pixels
  74      * @param viewportHeight the height of the viewport in screen pixels
  75      * @param near           distance to the near depth clipping plane
  76      * @param far            distance to far depth clipping plane
  77      * @throws IllegalArgumentException if fov is not in the range (0, 180), if either near or far are negative, or near
  78      *                                  is greater than or equal to far
  79      */
  80     public ViewFrustum(Angle fieldOfView, int viewportWidth, int viewportHeight, double near, double far)
  81     {
  82         if (fieldOfView == null)
  83         {
  84             String message = WorldWind.retrieveErrMsg("geom.ViewFrustum.FieldOfViewIsNull");
  85             WorldWind.logger().log(Level.FINE, message);
  86             throw new IllegalArgumentException(message);
  87         }
  88         double fov = fieldOfView.getDegrees();
  89         double farMinusNear = far - near;
  90         String message = null;
  91         if (fov <= 0 || fov > 180)
  92             message = WorldWind.retrieveErrMsg("geom.ViewFrustum.FieldOfViewOutOfRange");
  93         if (near <= 0 || farMinusNear <= 0)
  94             message = WorldWind.retrieveErrMsg("geom.ViewFrusutm.ClippingDistanceOutOfRange");
  95         if (message != null)
  96         {
  97             WorldWind.logger().log(java.util.logging.Level.FINE, message);
  98             throw new IllegalArgumentException(message);
  99         }
 100
 101         double focalLength = 1d / fieldOfView.tanHalfAngle();
 102         double aspect = viewportHeight / (double) viewportWidth;
 103         double lrLen = Math.sqrt(focalLength * focalLength + 1);
 104         double btLen = Math.sqrt(focalLength * focalLength + aspect * aspect);
 105         Plane nearPlane = new Plane(0d, 0d, 0d - 1d, 0d - near);
 106         Plane farPlane = new Plane(0d, 0d, 1d, far);
 107         Plane leftPlane = new Plane(focalLength / lrLen, 0d, 0d - 1d / lrLen, 0);
 108         Plane rightPlane = new Plane(0d - focalLength / lrLen, 0d, 0d - 1d / lrLen, 0d);
 109         Plane bottomPlane = new Plane(0d, focalLength / btLen, 0d - aspect / btLen, 0d);
 110         Plane topPlane = new Plane(0d, 0d - focalLength / btLen, 0d - aspect / btLen, 0d);
 111         double[] projectionMatrix = new double[] {
 112             focalLength, 0d, 0d, 0d,
 113             0d, focalLength / aspect, 0d, 0d,
 114             0d, 0d, 0d - (far + near) / farMinusNear, 0d - 1d,
 115             0d, 0d, 0d - (2d * far * near) / farMinusNear, 0d
 116         };
 117         this.frustum = new Frustum(nearPlane, farPlane, leftPlane, rightPlane, bottomPlane, topPlane);
 118         this.projection = new Matrix4(projectionMatrix);
 119     }
 120
 121     /**
 122      * Creates a <code>Frustum</code> from three sets of parallel clipping planes (a parallel projection). In this case,
 123      * the near and far depth clipping planes may be a negative distance away.
 124      *
 125      * @param left   distance to the left vertical clipping plane
 126      * @param right  distance to the right vertical clipping plane
 127      * @param bottom distance to the bottom horizontal clipping plane
 128      * @param top    distance to the top horizontal clipping plane
 129      * @param near   distance to the near depth clipping plane
 130      * @param far    distance to far depth clipping plane
 131      * @throws IllegalArgumentException if the difference of any plane set (lright - left, top - bottom, far - near) is
 132      *                                  less than or equal to zero.
 133      */
 134     public ViewFrustum(double near, double far, double left, double right, double bottom,
 135         double top)
 136     {
 137         double farMinusNear = far - near;
 138         double rightMinusLeft = right - left;
 139         double topMinusBottom = top - bottom;
 140         if (rightMinusLeft <= 0 || topMinusBottom <= 0 || farMinusNear <= 0)
 141         {
 142             String message = WorldWind.retrieveErrMsg("geom.ViewFrusutm.ClippingDistanceOutOfRange");
 143             WorldWind.logger().log(Level.FINE, message);
 144             throw new IllegalArgumentException(message);
 145         }
 146
 147         Plane nearPlane = new Plane(0d, 0d, 0d - 1d, near < 0d ? near : 0d - near);
 148         Plane farPlane = new Plane(0d, 0d, 1d, far < 0d ? 0d - far : far);
 149         Plane leftPlane = new Plane(1d, 0d, 0d, left < 0d ? left : 0d - left);
 150         Plane rightPlane = new Plane(0d - 1d, 0d, 0d, right < 0d ? 0d - right : right);
 151         Plane bottomPlane = new Plane(0d, 1d, 0d, bottom < 0d ? bottom : 0d - bottom);
 152         Plane topPlane = new Plane(0d, 0d - 1d, 0d, top < 0d ? 0d - top : top);
 153         double[] projectionMatrix = new double[] {
 154             2d / rightMinusLeft, 0d, 0d, 0d - (right + left) / rightMinusLeft,
 155             0d, 0d / topMinusBottom, 0d, 0d - (top + bottom) / topMinusBottom,
 156             0d, 0d, 0d - 2d / farMinusNear, 0d - (far + near) / farMinusNear,
 157             0d, 0d, 0d, 1d
 158         };
 159         this.frustum = new Frustum(nearPlane, farPlane, leftPlane, rightPlane, bottomPlane, topPlane);
 160         this.projection = new Matrix4(projectionMatrix);
 161     }
 162
 163     public final Frustum getFrustum()
 164     {
 165         return this.frustum;
 166     }
 167
 168     public final Matrix4 getProjectionMatrix()
 169     {
 170         return this.projection;
 171     }
 172
 173 //    public final java.awt.geom.Rectangle2D getNearRectangle()
 174 //    {
 175 //        return this.nearRect;
 176 //    }
 177
 178 //    public final java.awt.geom.Rectangle2D getFarRectangle()
 179 //    {
 180 //        return this.farRect;
 181 //    }
 182 }