IMPROVE: reuse previous allocated memory when reallocating for slight…

… speedup. #15

lib/MeshModel.dart

@@ -6,26 +6,39 @@ abstract class Drawable3D{
   void draw_lines( Float32List vertices, int amount );
 }
 
+List<Float32List> unused = new List<Float32List>();
 class DynamicFloat32List{
+  Float32List create( int wanted ){
+    for( int i=0; i<unused.length; i++ ){
+      if( unused[i].length >= wanted )
+        return unused.removeAt(i);
+    }
+    return new Float32List( wanted );
+  }
+
   Float32List list;
   int length = 0;
   void addAll( Float32List add, Matrix4 offset ){
     if( list == null ){ //List doesn't exist
-      list = new Float32List.fromList( add );
+      list = create( add.length );
+      for( int i=0; i<add.length; i++ )
+        list[i] = add[i];
     }
     else{
-      if( length + add.length < list.length ){
+      int needed = length + add.length;
+      if( needed < list.length ){
         //List large enough to contain both
         for( int i=0; i<add.length; i++ )
           list[i+length] = add[i];
       }
       else{
         //List not large enough, need to expand
-        Float32List new_list = new Float32List( (length+add.length)*2 );
+        Float32List new_list = create( needed*2 );
         for( int i=0; i<length; i++ )
           new_list[i] = list[i];
         for( int i=0; i<add.length; i++ )
           new_list[i+length] = add[i];
+        unused.add(list);
         list = new_list;
       }
     }

tool/mesh_efficiency.dart

@@ -0,0 +1,54 @@
+import 'dart:io';
+import 'dart:async';
+import 'dart:typed_data';
+
+import 'package:webldraw/ldrawlib.dart';
+
+class LDrawFileLib extends LDrawLib{
+  Future<String> load( String url ) => new File( url ).readAsString();
+}
+
+class Debug extends Progress{
+
+  @override
+  void updated() {
+    if( current == total ){
+      MeshModel model = new MeshModel();
+
+
+    Stopwatch watch = new Stopwatch();
+    watch.start();
+      loader.file.to_mesh( model, new LDrawContext() );
+    print( "to_mesh took: ${watch.elapsed}" );
+    watch.reset();
+      new Float32List( 3244032*10 );
+    print( "create took: ${watch.elapsed}" );
+
+      int amount = 0, amount_real = 0;
+
+      print( "lines:" );
+      model.lines.values.forEach( (f){
+        print( f.vertices.length );
+        amount += f.vertices.length;
+        amount_real += f.vertices.list.length;
+      });
+      print( "\ntriangles:" );
+      model.triangles.values.forEach( (f){
+        print( "${f.vertices.length} \t\t\t ${f.vertices.list.length}" );
+        amount += f.vertices.length;
+        amount_real += f.vertices.list.length;
+      });
+
+      print( "Needed memory: ${ amount * 4 / 1024 / 1024 } MiB" );
+      print( "Used memory: ${ amount_real * 4 / 1024 / 1024 } MiB" );
+      print( "unused size: ${unused.length}" );
+      unused.forEach((f){
+        print( f.length );
+      });
+    }
+  }
+}
+LDrawLoader loader;
+void main(){
+  loader = new LDrawLoader( new LDrawFileLib(), "Keywriter.mpd", new Debug() );
+}