From edd731b232ebb518eb173b4d3429402383587f04 Mon Sep 17 00:00:00 2001
From: David Rose <david@ddrose.com>
Date: Wed, 29 Jan 2014 17:30:40 +0000
Subject: [PATCH] copy_channel_masked()

---
 panda/src/pnmimage/pfmFile.cxx | 23 +++++++++++++++++++++++
 panda/src/pnmimage/pfmFile.h   |  1 +
 2 files changed, 24 insertions(+)

diff --git a/panda/src/pnmimage/pfmFile.cxx b/panda/src/pnmimage/pfmFile.cxx
index b78a3dcbab..06e13106bd 100644
--- a/panda/src/pnmimage/pfmFile.cxx
+++ b/panda/src/pnmimage/pfmFile.cxx
@@ -1467,6 +1467,29 @@ copy_channel(int to_channel, const PfmFile &other, int from_channel) {
   }
 }
 
+////////////////////////////////////////////////////////////////////
+//     Function: PfmFile::copy_channel_masked
+//       Access: Published
+//  Description: Copies just the specified channel values from the
+//               indicated PfmFile, but only where the other file has
+//               a data point.
+////////////////////////////////////////////////////////////////////
+void PfmFile::
+copy_channel_masked(int to_channel, const PfmFile &other, int from_channel) {
+  nassertv(is_valid() && other.is_valid());
+  nassertv(other._x_size == _x_size && other._y_size == _y_size);
+  nassertv(to_channel >= 0 && to_channel < get_num_channels() &&
+           from_channel >= 0 && from_channel < other.get_num_channels());
+
+  for (int yi = 0; yi < _y_size; ++yi) {
+    for (int xi = 0; xi < _x_size; ++xi) {
+      if (other.has_point(xi, yi)) {
+        set_channel(xi, yi, to_channel, other.get_channel(xi, yi, from_channel));
+      }
+    }
+  }
+}
+
 ////////////////////////////////////////////////////////////////////
 //     Function: PfmFile::apply_crop
 //       Access: Published
diff --git a/panda/src/pnmimage/pfmFile.h b/panda/src/pnmimage/pfmFile.h
index 723940ce5b..9a3cd444c4 100644
--- a/panda/src/pnmimage/pfmFile.h
+++ b/panda/src/pnmimage/pfmFile.h
@@ -121,6 +121,7 @@ PUBLISHED:
   BLOCKING void reverse_distort(const PfmFile &dist, PN_float32 scale_factor = 1.0);
   BLOCKING void merge(const PfmFile &other);
   BLOCKING void copy_channel(int to_channel, const PfmFile &other, int from_channel);
+  BLOCKING void copy_channel_masked(int to_channel, const PfmFile &other, int from_channel);
   BLOCKING void apply_crop(int x_begin, int x_end, int y_begin, int y_end);
   BLOCKING void clear_to_texcoords(int x_size, int y_size);