--- ray/src/common/interp2d.h	2013/02/11 23:33:35	2.5
+++ ray/src/common/interp2d.h	2013/02/14 19:57:10	2.7
@@ -1,4 +1,4 @@
-/* RCSid $Id: interp2d.h,v 2.5 2013/02/11 23:33:35 greg Exp $ */
+/* RCSid $Id: interp2d.h,v 2.7 2013/02/14 19:57:10 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		smul[2];	/* NI2DIM/(smax-smin) */
+	float		grid2;		/* twice 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;
 
@@ -49,6 +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
@@ -58,19 +68,19 @@ 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 that interpolates the function at that
- * location.
+ * 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 member,
+ * 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 either of the sampling functions.
+ * 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 > 1.0
+ * precisely.  Increase this setting by a factor > 1
  * with the interp2_smooth() call if greater mixing is desired.
- * A call of interp2_smooth(ip,0.0) resets to the minimum
+ * A call of interp2_smooth(ip,0) resets to the minimum
  * default.  It is not possible to "sharpen" the data.
  **************************************************************/