--- ray/src/common/interp2d.h	2013/02/11 22:56:22	2.4
+++ ray/src/common/interp2d.h	2013/02/15 01:26:47	2.8
@@ -1,4 +1,4 @@
-/* RCSid $Id: interp2d.h,v 2.4 2013/02/11 22:56:22 greg Exp $ */
+/* RCSid $Id: interp2d.h,v 2.8 2013/02/15 01:26:47 greg Exp $ */
 /*
  * Header for interpolation of anisotropic samples on 2-D plane.
  *
@@ -15,13 +15,20 @@ extern "C" {
 #define	NI2DSMF	0.42f			/* minimal smoothing factor */
 
 #define NI2DIR	(2*4)			/* # interpolation directions */
+#define NI2DIM	16			/* size of black flag array */
 
 /* Data structure for interpolant */
 typedef struct {
 	int		ns;		/* number of sample positions */
 	float		dmin;		/* minimum diameter (default=1) */
 	float		smf;		/* smoothing factor (def=NI2DSMF) */
-	unsigned short	(*da)[NI2DIR];	/* anisotropic distances (private) */
+	float		smin[2];	/* sample minima */
+	float		smax[2];	/* sample maxima */
+	float		grid2;		/* grid diameter squared */
+	struct interp2_samp {
+		unsigned short	dia[NI2DIR];
+		unsigned short	blkflg[NI2DIM];
+	}		*da;		/* direction array (private) */
 	float		spt[1][2];	/* sample positions (extends struct) */
 } INTERP2;
 
@@ -31,6 +38,12 @@ extern INTERP2	*interp2_alloc(int nsamps);
 /* Resize interpolation array (caller must assign any new values) */
 extern INTERP2	*interp2_realloc(INTERP2 *ip, int nsamps);
 
+/* Set minimum distance under which samples will start to merge */
+extern void	interp2_spacing(INTERP2 *ip, double mind);
+
+/* Modify smoothing parameter by the given factor */
+extern void	interp2_smooth(INTERP2 *ip, double sf);
+
 /* Assign full set of normalized weights to interpolate the given location */
 extern int	interp2_weights(float wtv[], INTERP2 *ip, double x, double y);
 
@@ -43,6 +56,9 @@ extern void	interp2_free(INTERP2 *ip);
 /* (Re)compute anisotropic basis function interpolant (normally automatic) */
 extern int	interp2_analyze(INTERP2 *ip);
 
+/* Compute unnormalized weight for a position relative to a sample */
+double		interp2_wti(INTERP2 *ip, const int i, double x, double y);
+
 /***************************************************************
  * Typical use is to allocate an INTERP2 struct and assign the
  * spt[] array with the ordered sample locations in x & y.  (The
@@ -52,19 +68,20 @@ extern int	interp2_analyze(INTERP2 *ip);
  * vector for all the samples, or interp2_topsamp() is called to
  * get the most important N samples for the specified location.
  * The weights (and indexes in the case of interp2_topsamp)
- * are then used as coefficients for corresponding sample values
- * in a vector sum together that interpolates the function at that
- * location.  Between the initial allocation call and the first
- * weight evaluation, the dmin member may be adjusted to
- * the distance under which samples will start to merge.  If this
- * parameter is later changed, interp2_analyze() should be called
- * to recompute the interpolant.
- * The smf member sets the smoothing factor for interpolation.
- * The default setting of NI2DSMF produces near-optimal
- * interpolation when well-separated sample values are known
- * precisely.  If a greater degree of mixing is desired, this
- * paremter may be increased and it will affect the next call
- * to interp2_weights() or interp2_topsamp().
+ * are then used as coefficients for corresponding sample
+ * values in a vector sum that interpolates the function at
+ * that location.
+ * The minimum distance between sample positions defaults to 1.0.
+ * Values spaced closer than this will be merged/averaged.
+ * The interp2_spacing() call may be used to alter this distance,
+ * causing the interpolant to be recalculated during the
+ * next call to the sampling functions.
+ * The default smoothing factor NI2DSMF provides near-optimal
+ * interpolation when well-separated values are known
+ * precisely.  Increase this setting by a factor > 1
+ * with the interp2_smooth() call if greater mixing is desired.
+ * A call of interp2_smooth(ip,0) resets to the minimum
+ * default.  It is not possible to "sharpen" the data.
  **************************************************************/
  
 #ifdef __cplusplus