add trival tool to dump three.js json mesh files

tool/threejs_json_dumper.dart

@@ -0,0 +1,145 @@
+import 'dart:io';
+import 'dart:convert';
+import 'package:args/args.dart';
+
+void DumpFaces(Map json, bool verbose) {
+  final List<int> faces = json["faces"];
+  int i = 0;
+  int count = 0;
+
+  int mVertex = 9;
+  int mUv = 0;
+  int mNormal = 0;
+  int mMat = 0;
+
+  while (i < faces.length) {
+    count++;
+    final int t = faces[i++];
+    final int d = (t & 1) == 0 ? 3 : 4; // quad or triangle
+    final bool hasMaterial = (t & 2) != 0;
+    final bool hasFaceVertexUv = (t & 8) != 0;
+    final bool hasFaceNormal = (t & 16) != 0;
+    final bool hasFaceVertexNormal = (t & 32) != 0;
+    final bool hasFaceColor = (t & 64) != 0;
+    final bool hasFaceVertexColor = (t & 128) != 0;
+    List<String> tokens = [];
+    tokens.add(t.toString());
+
+    tokens.add("  v: ");
+    for (int j = 0; j < d; j++) {
+      int x = faces[i++];
+      if (x > mVertex) mVertex = x;
+      tokens.add(x.toString());
+      tokens.add(" ");
+    }
+
+    if (hasMaterial) {
+      tokens.add("  m: ");
+      int x = faces[i++];
+      if (x > mMat) mMat = x;
+      tokens.add(x.toString());
+      tokens.add(" ");
+    }
+
+    if (hasFaceVertexUv) {
+      tokens.add("  uv: ");
+      for (int j = 0; j < d; j++) {
+        int x = faces[i++];
+        if (x > mUv) mUv = x;
+        tokens.add(x.toString());
+        tokens.add(" ");
+      }
+    }
+
+    if (hasFaceNormal) {
+      tokens.add("  fn: ");
+      int x = faces[i++];
+      if (x > mNormal) mNormal = x;
+      tokens.add(x.toString());
+      tokens.add(" ");
+    }
+
+    if (hasFaceVertexNormal) {
+      tokens.add("  n: ");
+      for (int j = 0; j < d; j++) {
+        int x = faces[i++];
+        if (x > mNormal) mNormal = x;
+        tokens.add(x.toString());
+        tokens.add(" ");
+      }
+    }
+
+    if (hasFaceColor) {
+      tokens.add("  fc: ");
+      int x = faces[i++];
+      tokens.add(x.toString());
+      tokens.add(" ");
+    }
+
+    if (hasFaceVertexColor) {
+      tokens.add("  c: ");
+      for (int j = 0; j < d; j++) {
+        int x = faces[i++];
+        tokens.add(x.toString());
+        tokens.add(" ");
+      }
+    }
+    if (verbose) {
+      print(tokens.join(""));
+    }
+  }
+
+  print("processed faces: ${count}");
+  print("max Material: ${mMat}");
+  print("max Vertex: ${mVertex}");
+  print("max UV: ${mUv}");
+  print("max Normal: ${mNormal}");
+}
+
+void ShowInfo(Map json) {
+  List materials = json["materials"];
+  List<double> vertices = json["vertices"];
+  List<double> normals = json["normals"];
+  List<double> colors = json["colors"];
+  List<double> uvs = [];
+  assert(json["uvs"].length <= 1);
+  if (json["uvs"].length == 1) {
+    uvs = json["uvs"][0];
+  }
+  List<int> faces = json["faces"];
+  List bones = json["bones"];
+  List<int> skinIndices = json["skinIndices"];
+  List<double> skinWeights = json["skinWeights"];
+  Map animation = json["animation"];
+  var metadata = json["metadata"];
+
+  print("meta: ${metadata}");
+  print("materials: ${materials.length}");
+  print("vertices: ${vertices.length}  ${vertices.length ~/ 3}");
+  print("normals: ${normals.length} ${normals.length ~/3}");
+  print("colors: ${colors.length}");
+  print("uvs: ${uvs.length}  ${uvs.length ~/ 2}");
+  print("faces: ${faces.length} ${faces.length ~/ 3}");
+  print("bones: ${bones.length}");
+  print("skinIndices: ${skinIndices.length} ${skinIndices.length ~/ 2}");
+  print("skinWeigths: ${skinWeights.length}");
+  print("animation: ${animation['name']}");
+}
+
+void main(List<String> arguments) {
+  final parser = new ArgParser()
+    ..addFlag("verbose", negatable: false, abbr: 'v');
+
+  ArgResults argResults = parser.parse(arguments);
+  List<String> paths = argResults.rest;
+  for (var p in paths) {
+    print("reading  ${p}");
+
+    print("reading mesh from: ${p}");
+    var meshData = new File(p).readAsStringSync();
+    var json = JSON.decode(meshData);
+    ShowInfo(json);
+    DumpFaces(json, argResults['verbose']);
+  }
+  return;
+}