From 7299a150c3b4855da46014420fb7f27c81ab24f7 Mon Sep 17 00:00:00 2001
From: David Rose <david@ddrose.com>
Date: Fri, 2 Nov 2012 01:14:51 +0000
Subject: [PATCH] raise precision of 16-bit image processing

---
 panda/src/grutil/pfmVizzer.cxx          | 28 ++++++++++++-------------
 panda/src/grutil/pfmVizzer.h            |  6 +++---
 panda/src/pnmimage/pnm-image-filter.cxx |  4 ++--
 3 files changed, 18 insertions(+), 20 deletions(-)

diff --git a/panda/src/grutil/pfmVizzer.cxx b/panda/src/grutil/pfmVizzer.cxx
index 9ba8d32a35..a9193614e6 100644
--- a/panda/src/grutil/pfmVizzer.cxx
+++ b/panda/src/grutil/pfmVizzer.cxx
@@ -312,12 +312,12 @@ generate_vis_mesh(MeshFace face) const {
 //               map.  This can be passed to make_displacement(); see
 //               that function for more information.
 ////////////////////////////////////////////////////////////////////
-int PfmVizzer::
+double PfmVizzer::
 calc_max_u_displacement() const {
   int x_size = _pfm.get_x_size();
   int y_size = _pfm.get_y_size();
 
-  int max_u = 0;
+  double max_u = 0;
 
   for (int yi = 0; yi < y_size; ++yi) {
     for (int xi = 0; xi < x_size; ++xi) {
@@ -326,10 +326,9 @@ calc_max_u_displacement() const {
       }
 
       const LPoint3f &point = _pfm.get_point(xi, yi);
-      double nxi = point[0] * (double)(x_size - 1) + 0.5;
-      double nyi = point[1] * (double)(y_size - 1) + 0.5;
+      double nxi = point[0] * (double)(x_size - 1);
 
-      max_u = max(max_u, (int)cceil(cabs(nxi - (double)xi)));
+      max_u = max(max_u, cabs(nxi - (double)xi));
     }
   }
 
@@ -344,12 +343,12 @@ calc_max_u_displacement() const {
 //               map.  This can be passed to make_displacement(); see
 //               that function for more information.
 ////////////////////////////////////////////////////////////////////
-int PfmVizzer::
+double PfmVizzer::
 calc_max_v_displacement() const {
   int x_size = _pfm.get_x_size();
   int y_size = _pfm.get_y_size();
 
-  int max_v = 0;
+  double max_v = 0;
 
   for (int yi = 0; yi < y_size; ++yi) {
     for (int xi = 0; xi < x_size; ++xi) {
@@ -358,9 +357,9 @@ calc_max_v_displacement() const {
       }
 
       const LPoint3f &point = _pfm.get_point(xi, yi);
-      double nyi = point[1] * (double)(y_size - 1) + 0.5;
+      double nyi = point[1] * (double)(y_size - 1);
 
-      max_v = max(max_v, (int)cceil(cabs(nyi - (double)yi)));
+      max_v = max(max_v, cabs(nyi - (double)yi));
     }
   }
 
@@ -386,13 +385,12 @@ calc_max_v_displacement() const {
 //               for max_u and max_v.
 ////////////////////////////////////////////////////////////////////
 void PfmVizzer::
-make_displacement(PNMImage &result, int max_u, int max_v) const {
+make_displacement(PNMImage &result, double max_u, double max_v) const {
   int x_size = _pfm.get_x_size();
   int y_size = _pfm.get_y_size();
   result.clear(x_size, y_size, 3, PNM_MAXMAXVAL);
   result.fill(0.5);
 
-
   for (int yi = 0; yi < y_size; ++yi) {
     for (int xi = 0; xi < x_size; ++xi) {
       if (!_pfm.has_point(xi, yi)) {
@@ -400,11 +398,11 @@ make_displacement(PNMImage &result, int max_u, int max_v) const {
       }
 
       const LPoint3f &point = _pfm.get_point(xi, yi);
-      double nxi = point[0] * (double)(x_size - 1) + 0.5;
-      double nyi = point[1] * (double)(y_size - 1) + 0.5;
+      double nxi = point[0] * (double)(x_size - 1);
+      double nyi = point[1] * (double)(y_size - 1);
 
-      double u_shift = (nxi - (double)xi) / (double)max_u;
-      double v_shift = (nyi - (double)yi) / (double)max_v;
+      double u_shift = (nxi - (double)xi) / max_u;
+      double v_shift = (nyi - (double)yi) / max_v;
 
       result.set_red(xi, yi, u_shift * 0.5 + 0.5);
       result.set_green(xi, yi, v_shift * 0.5 + 0.5);
diff --git a/panda/src/grutil/pfmVizzer.h b/panda/src/grutil/pfmVizzer.h
index 0c80658a20..e33af79c5b 100644
--- a/panda/src/grutil/pfmVizzer.h
+++ b/panda/src/grutil/pfmVizzer.h
@@ -74,9 +74,9 @@ PUBLISHED:
   };
   BLOCKING NodePath generate_vis_mesh(MeshFace face = MF_front) const;
 
-  BLOCKING int calc_max_u_displacement() const;
-  BLOCKING int calc_max_v_displacement() const;
-  BLOCKING void make_displacement(PNMImage &result, int max_u, int max_v) const;
+  BLOCKING double calc_max_u_displacement() const;
+  BLOCKING double calc_max_v_displacement() const;
+  BLOCKING void make_displacement(PNMImage &result, double max_u, double max_v) const;
 
 private:
   void make_vis_mesh_geom(GeomNode *gnode, bool inverted) const;
diff --git a/panda/src/pnmimage/pnm-image-filter.cxx b/panda/src/pnmimage/pnm-image-filter.cxx
index d08906f30e..a54a936595 100644
--- a/panda/src/pnmimage/pnm-image-filter.cxx
+++ b/panda/src/pnmimage/pnm-image-filter.cxx
@@ -62,19 +62,19 @@
 // are usually 8 bits per channel), it doesn't cost any precision at all to
 // use shorts, and not very much to use chars.
 
-/*
 // To use double-precision floating point, 8 bytes: (strictly for the neurotic)
 typedef double WorkType;
 typedef double StoreType;
 static const WorkType source_max = 1.0;
 static const WorkType filter_max = 1.0;
-*/
 
+/*
 // To use single-precision floating point, 4 bytes:
 typedef double WorkType;
 typedef float StoreType;
 static const WorkType source_max = 1.0;
 static const WorkType filter_max = 1.0;
+*/
 
 /*
 // To use 16-bit integer arithmetic, 2 bytes: