Add Draco 1.3.6 to third_party.

third_party/draco/docs/spec/sequential.integer.attribute.decoder.md

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+
+## Sequential Integer Attribute Decoder
+
+### ConvertSymbolToSignedInt()
+
+~~~~~
+int ConvertSymbolToSignedInt(val) {
+  is_positive = !(val & 1);
+  val >>= 1;
+  if (is_positive) {
+    return val;
+  }
+  val = -val - 1;
+  return val;
+}
+~~~~~
+{:.draco-syntax }
+
+
+### ConvertSymbolsToSignedInts()
+
+~~~~~
+void ConvertSymbolsToSignedInts() {
+  decoded_symbols = seq_int_att_dec_decoded_values[curr_att_dec][curr_att];
+  for (i = 0; i < decoded_symbols.size(); ++i) {
+    val = ConvertSymbolToSignedInt(decoded_symbols[i]);
+    seq_int_att_dec_symbols_to_signed_ints[i] = val;
+  }
+}
+~~~~~
+{:.draco-syntax }
+
+
+### SequentialIntegerAttributeDecoder_DecodeIntegerValues()
+
+~~~~~
+void SequentialIntegerAttributeDecoder_DecodeIntegerValues() {
+  num_components = GetNumComponents();
+  num_entries = att_dec_num_values_to_decode[curr_att_dec][curr_att];
+  num_values = num_entries * num_components;
+  if (seq_int_att_dec_compressed[curr_att_dec][curr_att] > 0) {
+    DecodeSymbols(num_values, num_components, &decoded_symbols);
+  }
+  seq_int_att_dec_decoded_values[curr_att_dec][curr_att] = decoded_symbols;
+  if (num_values > 0) {
+    if (seq_att_dec_prediction_transform_type[curr_att_dec][curr_att] ==
+          PREDICTION_TRANSFORM_NORMAL_OCTAHEDRON_CANONICALIZED) {
+      decoded_symbols = seq_int_att_dec_decoded_values[curr_att_dec][curr_att];
+      for (i = 0; i < decoded_symbols.size(); ++i) {
+        signed_vals[i] = decoded_symbols[i];
+      }
+      seq_int_att_dec_symbols_to_signed_ints[curr_att_dec][curr_att] = signed_vals;
+    } else {
+      ConvertSymbolsToSignedInts();
+    }
+  }
+  if (seq_att_dec_prediction_scheme[curr_att_dec][curr_att] != PREDICTION_NONE) {
+    DecodePredictionData(seq_att_dec_prediction_scheme[curr_att_dec][curr_att]);
+    PredictionScheme_ComputeOriginalValues(
+        seq_att_dec_prediction_scheme[curr_att_dec][curr_att], num_entries);
+  }
+}
+~~~~~
+{:.draco-syntax }