add :powertwo option

pandatool/src/egg-palettize/eggPalettize.cxx

@@ -430,6 +430,12 @@ describe_input_file() {
             "also be overridden for a particular texture using the 'coverage' "
             "keyword on the texture line.\n\n");
 
+  show_text("  :powertwo flag", 10,
+            "Specifies whether textures should be forced to a power of two "
+            "size when they are not placed within a palette.  Use 1 for true, "
+            "to force textures to a power of two; or 0 to leave them exactly "
+            "the size they are specified.  The default is true.\n\n");
+
   show_text("  :round fraction fuzz", 10,
             "When the coverage area is computed, it may optionally be "
             "rounded up to the next sizeable unit before placing the "

pandatool/src/palettizer/txaFile.cxx

@@ -77,6 +77,9 @@ read(istream &in, const string &filename) {
       } else if (words[0] == ":coverage") {
         okflag = parse_coverage_line(words);
 
+      } else if (words[0] == ":powertwo") {
+        okflag = parse_powertwo_line(words);
+
       } else if (words[0] == ":imagetype") {
         okflag = parse_imagetype_line(words);
 
@@ -400,6 +403,37 @@ parse_coverage_line(const vector_string &words) {
   return true;
 }
 
+////////////////////////////////////////////////////////////////////
+//     Function: TxaFile::parse_powertwo_line
+//       Access: Private
+//  Description: Handles the line in a .txa file that begins with the
+//               keyword ":powertwo" and indicates whether textures
+//               should by default be forced to a power of two.
+////////////////////////////////////////////////////////////////////
+bool TxaFile::
+parse_powertwo_line(const vector_string &words) {
+  if (words.size() != 2) {
+    nout << "Exactly one parameter required for :powertwo, either a 0 "
+         << "or a 1.\n";
+    return false;
+  }
+
+  int flag;
+  if (!string_to_int(words[1], flag)) {
+    nout << "Invalid powertwo flag: " << words[1] << "\n";
+    return false;
+  }
+
+  if (flag != 0 && flag != 1) {
+    nout << "Invalid powertwo flag: " << flag << "\n";
+    return false;
+  }
+
+  pal->_force_power_2 = (flag != 0);
+
+  return true;
+}
+
 ////////////////////////////////////////////////////////////////////
 //     Function: TxaFile::parse_imagetype_line
 //       Access: Private

pandatool/src/palettizer/txaFile.h

@@ -53,6 +53,7 @@ private:
   bool parse_margin_line(const vector_string &words);
   bool parse_background_line(const vector_string &words);
   bool parse_coverage_line(const vector_string &words);
+  bool parse_powertwo_line(const vector_string &words);
   bool parse_imagetype_line(const vector_string &words);
   bool parse_shadowtype_line(const vector_string &words);
   bool parse_round_line(const vector_string &words);