Added OrthographicCamera class and factored out computation of start

point for ray picking into abstract Camera.getRayStartPoint(). Tested
by temporarily modifying DisplayShelf demo to use an orthographic
camera -- appears to be working.


git-svn-id: file:///usr/local/projects/SUN/JOGL/git-svn/svn-server-sync/joglutils/trunk@63 83d24430-9974-4f80-8418-2cc3294053b9

3 files changed, 125 insertions, 4 deletions

diff --git a/src/net/java/joglutils/msg/nodes/Camera.java b/src/net/java/joglutils/msg/nodes/Camera.java
index 04380f1..8dc63d4 100644
--- a/src/net/java/joglutils/msg/nodes/Camera.java
+++ b/src/net/java/joglutils/msg/nodes/Camera.java
@@ -216,18 +216,21 @@ public abstract class Camera extends Node {
     Vec3f to = new Vec3f(unproj.x() * ooZ,
                          unproj.y() * ooZ,
                          unproj.z() * ooZ);
-    // FIXME: for orthographic projections, need to do something
-    // different; can't just use the eye point
-    Vec3f from = getPosition();
+    Vec3f from = getRayStartPoint(point, to);
     Vec3f dir  = to.minus(from);
 
-    //    System.err.println("unprojected point: " + from);
+    //    System.err.println("unprojected point: " + to);
     //    System.err.println("unprojected dir  : " + dir);
 
     line.setPoint(from);
     line.setDirection(dir);
   }
 
+  /** Computes the start point of a ray for picking, given a point in
+      normalized screen coordinates ((0, 0) to (1, 1)) and a 3D point
+      which that point unprojects to. */
+  protected abstract Vec3f getRayStartPoint(Vec2f point, Vec3f unprojectedPoint);
+
   public void doAction(Action action) {
     if (ViewingMatrixElement.isEnabled(action.getState())) {
       ViewingMatrixElement.set(action.getState(), getViewingMatrix());
diff --git a/src/net/java/joglutils/msg/nodes/OrthographicCamera.java b/src/net/java/joglutils/msg/nodes/OrthographicCamera.java
new file mode 100644
index 0000000..0678acd
--- /dev/null
+++ b/src/net/java/joglutils/msg/nodes/OrthographicCamera.java
@@ -0,0 +1,114 @@
+/*
+ * 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.*;
+
+public class OrthographicCamera extends Camera {
+  private static final float DEFAULT_HEIGHT = 2.0f;
+  // Amount the most recently set height differed from the default
+  private float heightScale = 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 height = heightScale * DEFAULT_HEIGHT;
+      float width  = height * aspect;
+
+      if ((height == 0) || (width == 0) || (deltaZ == 0))
+        return projMatrix;
+
+      // This is a simplified version of the orthographic camera
+      // matrix where it's symmetric about the origin
+      projMatrix.set(0, 0,  2.0f / width);
+      projMatrix.set(1, 1,  2.0f / height);
+      projMatrix.set(2, 2, -2.0f / deltaZ);
+    }
+
+    return projMatrix;
+  }
+
+  /** Sets the height, in units, of the volume this orthographic
+      camera views. The default height is 2.0 units. */
+  public void setHeight(float height) {
+    heightScale = height / DEFAULT_HEIGHT;
+  }
+
+  /** Returns the height, in units, of the volume this orthographic
+      camera views. */
+  public float getHeight() {
+    return heightScale * DEFAULT_HEIGHT;
+  }
+
+  /** Returns the width, in units, of the volume this orthographic
+      camera views, assuming the passed-in aspect ratio. */
+  public float getWidth(float aspectRatio) {
+    return getHeight() * aspectRatio;
+  }
+
+  /** Returns the width, in units, of the volume this orthographic
+      camera views, assuming the camera's currently-set aspect
+      ratio. */
+  public float getWidth() {
+    return getWidth(getAspectRatio());
+  }
+
+  protected Vec3f getRayStartPoint(Vec2f point, Vec3f unprojectedPoint) {
+    // The easiest way to compute a reasonable ray start point is to
+    // start from the unprojected 3D point and go back along the Z-axis
+    Vec3f backward = Vec3f.Z_AXIS.times(getNearDistance());
+    backward = getOrientation().rotateVector(backward);
+    return unprojectedPoint.plus(backward);
+  }
+
+  public void render(GLRenderAction action) {
+    // FIXME: unclear whether we should be doing this, or whether we
+    // should have a mechanism which doesn't require mutation of the
+    // camera
+    setAspectRatio(action.getCurAspectRatio());
+    doAction(action);
+  }
+}
diff --git a/src/net/java/joglutils/msg/nodes/PerspectiveCamera.java b/src/net/java/joglutils/msg/nodes/PerspectiveCamera.java
index 0bffd88..d2eb082 100644
--- a/src/net/java/joglutils/msg/nodes/PerspectiveCamera.java
+++ b/src/net/java/joglutils/msg/nodes/PerspectiveCamera.java
@@ -105,6 +105,10 @@ public class PerspectiveCamera extends Camera {
     return getWidthAngle(getAspectRatio());
   }
 
+  protected Vec3f getRayStartPoint(Vec2f point, Vec3f unprojectedPoint) {
+    return getPosition();
+  }
+
   public void render(GLRenderAction action) {
     // FIXME: unclear whether we should be doing this, or whether we
     // should have a mechanism which doesn't require mutation of the