Initial checkin of the Minimal Scene Graph (MSG) library, intentended

for experimentation with both 3D and 2D/3D interaction.


git-svn-id: file:///usr/local/projects/SUN/JOGL/git-svn/svn-server-sync/joglutils/trunk@44 83d24430-9974-4f80-8418-2cc3294053b9

1 files changed, 97 insertions, 0 deletions

diff --git a/src/net/java/joglutils/msg/nodes/PerspectiveCamera.java b/src/net/java/joglutils/msg/nodes/PerspectiveCamera.java
new file mode 100644
index 0000000..b72507a
--- /dev/null
+++ b/src/net/java/joglutils/msg/nodes/PerspectiveCamera.java
@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2007 Sun Microsystems, Inc. All Rights Reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * 
+ * - Redistribution of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * 
+ * - Redistribution 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 Sun Microsystems, Inc. or the names of
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ * 
+ * This software is provided "AS IS," without a warranty of any kind. ALL
+ * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
+ * INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
+ * PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN
+ * MICROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL NOT BE LIABLE FOR
+ * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
+ * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR
+ * ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR
+ * DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE
+ * DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY,
+ * ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, EVEN IF
+ * SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
+ * 
+ * You acknowledge that this software is not designed or intended for use
+ * in the design, construction, operation or maintenance of any nuclear
+ * facility.
+ * 
+ */
+
+package net.java.joglutils.msg.nodes;
+
+import net.java.joglutils.msg.actions.*;
+import net.java.joglutils.msg.math.*;
+
+/** Represents a camera utilizing a perspective projection. <P>
+
+    The default height angle is Math.PI / 4 radians (45 degrees),
+    meaning that the camera has a total vertical field of view of 90
+    degrees.
+*/
+
+public class PerspectiveCamera extends Camera {
+  private static final float DEFAULT_HEIGHT_ANGLE = (float) (Math.PI / 4);
+  // Amount the most recently set height angle differed from the default
+  private float vertFOVScale = 1.0f;
+  
+  public Mat4f getProjectionMatrix() {
+    if (projDirty) {
+      projMatrix.makeIdent();
+      projDirty = false;
+
+      // Recompute matrix based on current parameters
+      float zNear = getNearDistance();
+      float zFar  = getFarDistance();
+      float deltaZ = zFar - zNear;
+      float aspect = getAspectRatio();
+      float radians = vertFOVScale * DEFAULT_HEIGHT_ANGLE;
+      float sine = (float) Math.sin(radians);
+      if ((deltaZ == 0) || (sine == 0) || (aspect == 0)) {
+        return projMatrix;
+      }
+      
+      float cotangent = (float) Math.cos(radians) / sine;
+      projMatrix.set(0, 0, cotangent / aspect);
+      projMatrix.set(1, 1, cotangent);
+      projMatrix.set(2, 2, -(zFar + zNear) / deltaZ);
+      projMatrix.set(3, 2, -1);
+      projMatrix.set(2, 3, -2 * zNear * zFar / deltaZ);
+      projMatrix.set(3, 3, 0);
+    }
+
+    return projMatrix;
+  }
+
+  /** Sets the height angle of this perspective camera. */
+  public void setHeightAngle(float heightAngle) {
+    vertFOVScale = heightAngle / DEFAULT_HEIGHT_ANGLE;
+    projDirty = true;
+  }
+
+  /** Returns the height angle of this perspective camera. */
+  public float getHeightAngle() {
+    return vertFOVScale * DEFAULT_HEIGHT_ANGLE;
+  }
+
+  public void doAction(Action action) {
+    action.visit(this);
+  }
+}