1 files changed, 153 insertions, 0 deletions
diff --git a/proto/vector_tile.proto b/proto/vector_tile.proto
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+// Protocol Version 1
+
+package llmr.vector;
+
+option optimize_for = LITE_RUNTIME;
+
+enum geom_type {
+    Unknown = 0;
+    Point = 1;
+    LineString = 2;
+    Polygon = 3;
+}
+
+// Variant type encoding
+message value {
+    // Exactly one of these values may be present in a valid message
+    optional string string_value = 1;
+    optional float float_value = 2;
+    optional double double_value = 3;
+    optional int64 int_value = 4;
+    optional uint64 uint_value = 5;
+    optional sint64 sint_value = 6;
+    optional bool bool_value = 7;
+
+    extensions 8 to max;
+}
+
+message feature {
+    optional uint64 id = 1;
+
+    // Tags of this feature. Even numbered values refer to the nth
+    // value in the keys list on the tile message, odd numbered
+    // values refer to the nth value in the values list on the tile
+    // message.
+    repeated uint32 tags = 2 [ packed = true ];
+
+    // The type of geometry stored in this feature.
+    optional geom_type type = 3 [ default = Unknown ];
+
+    // Contains a stream of commands and parameters (vertices). The
+    // repeat count is shifted to the left by 3 bits. This means
+    // that the command has 3 bits (0-15). The repeat count
+    // indicates how often this command is to be repeated. Defined
+    // commands are:
+    // - MoveTo:    1   (2 parameters follow)
+    // - LineTo:    2   (2 parameters follow)
+    // - ClosePath: 15  (no parameters follow)
+    //
+    // Ex.: MoveTo(3, 6), LineTo(8, 12), LineTo(20, 34), ClosePath
+    // Encoded as: [ 3 6 18 5 6 12 22 15 ]
+    //                                == command type 15 (ClosePath)
+    //                          ===== relative LineTo(+12, +22) == LineTo(20, 34)
+    //                      === relative LineTo(+5, +6) == LineTo(8, 12)
+    //                   == [00010 010] = command type 2 (LineTo), length 2
+    //               === relative MoveTo(+3, +6)
+    //             = implicit command type 1 (MoveTo), length 1
+    // Commands are encoded as uint32 varints, vertex parameters are
+    // encoded as sint32 varints (zigzag). Vertex parameters are
+    // also encoded as deltas to the previous position. The original
+    // position is (0,0)
+    repeated uint32 geometry = 4 [ packed = true ];
+
+    // A list of indices to the geometry array that specify a triangulation of
+    // this geometry. This must only exist if this feature is a polygon.
+    // These are the valid indices for the example above:
+    //     0 ==>  (3/6)
+    //     1 ==>  (8/12)
+    //     2 ==> (20/34)
+    // Indices beyond 2 are invalid, as the total number of vertices is 3.
+    repeated sint32 triangulation = 5 [ packed = true ];
+
+    // The total number of vertices encoded in the geometry field. This is can
+    // be deduced by manually iterating through the geometry field, but we can
+    // just as well store the number to avoid the overhead on parsing.
+    optional uint32 vertex_count = 6;
+}
+
+// Stores a glyph with metrics and optional SDF bitmap information.
+message glyph {
+    required uint32 id = 1;
+
+    // A signed distance field of the glyph with a border of 3 pixels.
+    optional bytes bitmap = 2;
+
+    // Glyph metrics.
+    required uint32 width = 3;
+    required uint32 height = 4;
+    required sint32 left = 5;
+    required sint32 top = 6;
+    required uint32 advance = 7;
+}
+
+// Stores font face information and a list of glyphs.
+message face {
+    required string family = 1;
+    required string style = 2;
+    repeated glyph glyphs = 5;
+}
+
+// Stores the shaping information for the label with a given text
+message label {
+    // The original value ID this shaping information is for.
+    required uint32 text = 1;
+
+    // References the index of the font stack in the layer's fontstack array.
+    required uint32 stack = 2;
+
+    // Parallel arrays of face ID, glyph ID and position.
+    repeated uint32 faces = 3  [packed = true];
+    repeated uint32 glyphs = 4 [packed = true];
+    repeated uint32 x = 5  [packed = true];
+    repeated uint32 y = 6  [packed = true];
+}
+
+message layer {
+    // Any compliant implementation must first read the version
+    // number encoded in this message and choose the correct
+    // implementation for this version number before proceeding to
+    // decode other parts of this message.
+    required uint32 version = 15 [ default = 1 ];
+
+    required string name = 1;
+
+    // The actual features in this tile.
+    repeated feature features = 2;
+
+    // Dictionary encoding for keys
+    repeated string keys = 3;
+
+    // Dictionary encoding for values
+    repeated value values = 4;
+
+    // The bounding box in this tile spans from 0..4095 units
+    optional uint32 extent = 5 [ default = 4096 ];
+
+    // Total vertex count in this layer.
+    optional uint32 vertex_count = 6;
+
+    // Shaping information for labels contained in this tile.
+    repeated string faces = 7;
+    repeated label labels = 8;
+    repeated string stacks = 9;
+
+    extensions 16 to max;
+}
+
+message tile {
+    repeated layer layers = 3;
+
+    repeated face faces = 4;
+
+    extensions 16 to 8191;
+}