Fixed a bug with the texture controllers and moved some shared code into

a utility class.


git-svn-id: svn+ssh://src.earth.threerings.net/nenya/trunk@132 ed5b42cb-e716-0410-a449-f6a68f950b19

src/java/com/threerings/jme/util/JmeUtil.java

@@ -0,0 +1,127 @@
+//
+// $Id: SpatialVisitor.java 119 2007-01-24 00:22:12Z dhoover $
+
+package com.threerings.jme.util;
+
+import com.jme.math.Vector3f;
+import com.jme.scene.Controller;
+
+import com.samskivert.util.StringUtil;
+
+import com.threerings.jme.Log;
+
+/**
+ * Some static classes and methods of general utility to applications using JME.
+ */
+public class JmeUtil
+{
+    /**
+     * Represents the current position and direction in an animation composed of a fixed number of
+     * discrete frames using one of the repeat types defined in {@link Controller}.
+     */
+    public static class FrameState
+    {
+        /** The index of the current frame. */
+        public int idx;
+        
+        /** The current direction of animation. */
+        public int dir = +1;
+        
+        /** The fractional progress towards the next frame. */
+        public float accum;
+        
+        /**
+         * Resets the state back to the beginning.
+         */
+        public void reset ()
+        {
+            set(0, +1, 0f);
+        }
+        
+        /**
+         * Sets the entire frame state.
+         */
+        public void set (int idx, int dir, float accum)
+        {
+            this.idx = idx;
+            this.dir = dir;
+            this.accum = accum;
+        }
+        
+        /**
+         * Updates the frame state after some amount of time has elapsed.
+         */
+        public void update (float elapsed, float frameRate, int frameCount, int repeatType)
+        {
+            float frames = elapsed * frameRate;
+            for (accum += frames; accum >= 1f; accum -= 1f) {
+                advance(frameCount, repeatType);
+            }
+        }
+        
+        /**
+         * Advances the position by one frame.
+         */
+        public void advance (int frameCount, int repeatType)
+        {
+            if ((idx += dir) >= frameCount) {
+                if (repeatType == Controller.RT_CLAMP) {
+                    idx = frameCount - 1;
+                    dir = 0;
+                } else if (repeatType == Controller.RT_WRAP) {
+                    idx = 0;
+                } else { // repeatType == Controller.RT_CYCLE
+                    idx = frameCount - 2;
+                    dir = -1;
+                }
+            } else if (idx < 0) {
+                idx = 1;
+                dir = +1;
+            }
+        }
+    }
+    
+    /**
+     * Attempts to parse a string containing an axis: either "x", "y", or "z", or three
+     * comma-delimited values representing an axis vector.  The value returned may be one of
+     * JME's "constant" vectors (for example, {@link Vector3f#UNIT_X}), so don't modify it.
+     */
+    public static Vector3f parseAxis (String axis)
+    {
+        if (axis == null) {
+            return null;
+        }
+        if (axis.equalsIgnoreCase("x")) {
+            return Vector3f.UNIT_X;
+        } else if (axis.equalsIgnoreCase("y")) {
+            return Vector3f.UNIT_Y;
+        } else if (axis.equalsIgnoreCase("z")) {
+            return Vector3f.UNIT_Z;
+        }
+        float[] vals = StringUtil.parseFloatArray(axis);
+        if (vals != null && vals.length == 3) {
+            return new Vector3f(vals[0], vals[1], vals[2]).normalizeLocal();
+        } else {
+            Log.warning("Invalid axis [axis=" + axis + "].");
+            return null;
+        }
+    }
+    
+    /**
+     * Attempts to parse a string describing one of the repeat types defined in {@link Controller}:
+     * "clamp", "cycle", or "wrap".  Will return {@link Controller#RT_WRAP} if the type is
+     * <code>null</code> or invalid.
+     */
+    public static int parseRepeatType (String type)
+    {
+        if ("clamp".equals(type)) {
+            return Controller.RT_CLAMP;
+        } else if ("cycle".equals(type)) {
+            return Controller.RT_CYCLE;
+        }
+        if (type != null && !"wrap".equals(type)) {
+            Log.warning("Invalid repeat type [type=" + type + "].");
+        }
+        return Controller.RT_WRAP;   
+    }
+}