[Teem-commit] SF.net SVN: teem:[7136] teem/trunk/src/seek/extract.c

[<kin...@us...>]

Revision: 7136
          http://sourceforge.net/p/teem/code/7136
Author:   kindlmann
Date:     2023-07-22 03:55:59 +0000 (Sat, 22 Jul 2023)
Log Message:
-----------
API CHANGE: adding another field to seekContext, to record the average (world-space) gradient magnitude, over the vertices in an isosurface (when there isn't a gageContext), with the hope that it is useful for some signed distance field computations. Also noting that Thomas Schultz commited some work to this file (other files in seek have a similar copyright attribution)

Modified Paths:
--------------
    teem/trunk/src/seek/extract.c

Modified: teem/trunk/src/seek/extract.c
===================================================================
--- teem/trunk/src/seek/extract.c	2023-07-22 03:51:29 UTC (rev 7135)
+++ teem/trunk/src/seek/extract.c	2023-07-22 03:55:59 UTC (rev 7136)
@@ -1,6 +1,7 @@
 /*
   Teem: Tools to process and visualize scientific data and images
   Copyright (C) 2009--2023  University of Chicago
+  Copyright (C) 2009, 2011  Thomas Schultz
   Copyright (C) 2005--2008  Gordon Kindlmann
   Copyright (C) 1998--2004  University of Utah
 
@@ -825,6 +826,9 @@
             if (sctx->normAns) {
               gageProbe(sctx->gctx, tvertB[0], tvertB[1], tvertB[2]);
               ELL_3V_SCALE_TT(lpld->norm + 3 * ovi, float, -1, sctx->normAns);
+              /* alas we can't increment sctx->gradMagAvg here because we only have the
+               * already-normalized normal, and updateSeek.c/updateAnswerPointers()
+               * actually prevents us from setting a gradAns if we wanted to */
               if (sctx->reverse) {
                 ELL_3V_SCALE(lpld->norm + 3 * ovi, -1, lpld->norm + 3 * ovi);
               }
@@ -832,6 +836,7 @@
               ELL_3V_LERP(grad, ww, vgrad[vi0], vgrad[vi1]);
               ELL_3MV_MUL(tvec, sctx->txfNormal, grad);
               ELL_3V_NORM_TT(lpld->norm + 3 * ovi, float, tvec, tlen);
+              sctx->gradMagAvg += tlen;
             }
           }
           sctx->vertNum++;
@@ -889,6 +894,9 @@
     return 1;
   }
 
+  sctx->gradMagAvg = 0; /* initalize per-vert accumulator, even though it will be
+                           incremented in a narrow range of circumstances (such as:
+                           isocontours without a gageContext) */
   if (sctx->verbose > 2) {
     fprintf(stderr, "%s: extracting ...       ", me);
   }
@@ -913,6 +921,9 @@
   if (sctx->verbose > 2) {
     fprintf(stderr, "%s\n", airDoneStr(0, zi, sz - 2, done));
   }
+  if (sctx->vertNum) {
+    sctx->gradMagAvg /= sctx->vertNum;
+  }
 
   /* this cleans up the airArrays in bag */
   baggageNix(bag);

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