1 files changed, 81 insertions, 0 deletions
diff --git a/engine/src/core/com/jme3/shadow/PssmShadowUtil.java b/engine/src/core/com/jme3/shadow/PssmShadowUtil.java
new file mode 100644
index 0000000..2633625
--- /dev/null
+++ b/engine/src/core/com/jme3/shadow/PssmShadowUtil.java
@@ -0,0 +1,81 @@
+/*
+ * 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.shadow;
+
+import com.jme3.bounding.BoundingBox;
+import com.jme3.math.FastMath;
+import com.jme3.math.Matrix4f;
+import com.jme3.renderer.Camera;
+import com.jme3.renderer.queue.GeometryList;
+import static java.lang.Math.max;
+import static java.lang.Math.min;
+
+/**
+ * Includes various useful shadow mapping functions.
+ *
+ * @see
+ * <ul>
+ * <li><a href="http://appsrv.cse.cuhk.edu.hk/~fzhang/pssm_vrcia/">http://appsrv.cse.cuhk.edu.hk/~fzhang/pssm_vrcia/</a></li>
+ * <li><a href="http://http.developer.nvidia.com/GPUGems3/gpugems3_ch10.html">http://http.developer.nvidia.com/GPUGems3/gpugems3_ch10.html</a></li>
+ * </ul>
+ * for more info.
+ */
+public final class PssmShadowUtil {
+
+    /**
+     * Updates the frustum splits stores in <code>splits</code> using PSSM.
+     */
+    public static void updateFrustumSplits(float[] splits, float near, float far, float lambda) {
+        for (int i = 0; i < splits.length; i++) {
+            float IDM = i / (float) splits.length;
+            float log = near * FastMath.pow((far / near), IDM);
+            float uniform = near + (far - near) * IDM;
+            splits[i] = log * lambda + uniform * (1.0f - lambda);
+        }
+
+        // This is used to improve the correctness of the calculations. Our main near- and farplane
+        // of the camera always stay the same, no matter what happens.
+        splits[0] = near;
+        splits[splits.length - 1] = far;
+    }
+
+    /**
+     * Compute the Zfar in the model vieuw to adjust the Zfar distance for the splits calculation
+     */
+    public static float computeZFar(GeometryList occ, GeometryList recv, Camera cam) {
+        Matrix4f mat = cam.getViewMatrix();
+        BoundingBox bbOcc = ShadowUtil.computeUnionBound(occ, mat);
+        BoundingBox bbRecv = ShadowUtil.computeUnionBound(recv, mat);
+
+        return min(max(bbOcc.getZExtent() - bbOcc.getCenter().z, bbRecv.getZExtent() - bbRecv.getCenter().z), cam.getFrustumFar());
+    }
+}