Add 'best' game piece

Chooses the best game piece based on proximity to (x, y) cordinates.

Signed-off-by: Filip Kujawa <filip.j.kujawa@gmail.com>
Change-Id: I67ddbd749137e95b99a1d215373aeb044c949667
diff --git a/y2023/vision/game_pieces.cc b/y2023/vision/game_pieces.cc
index 868d5b0..0e2546f 100644
--- a/y2023/vision/game_pieces.cc
+++ b/y2023/vision/game_pieces.cc
@@ -1,44 +1,96 @@
 #include "y2023/vision/game_pieces.h"
 
+#include <ctime>
+
 #include "aos/events/event_loop.h"
 #include "aos/events/shm_event_loop.h"
 #include "frc971/vision/vision_generated.h"
 
+// The best_x and best_y are pixel (x, y) cordinates. The 'best'
+// game piece is picked on proximity to the specified cordinates.
+// The cordinate should represent where we want to intake a game piece.
+// (0, 360) was chosen without any testing, just a cordinate that
+// seemed reasonable.
+
+DEFINE_uint32(
+    best_x, 0,
+    "The 'best' game piece is picked based on how close it is to this x value");
+
+DEFINE_uint32(
+    best_y, 360,
+    "The 'best' game piece is picked based on how close it is to this y value");
+
 namespace y2023 {
 namespace vision {
 GamePiecesDetector::GamePiecesDetector(aos::EventLoop *event_loop)
-    : game_pieces_sender_(
-          event_loop->MakeSender<GamePieces>("/camera")) {
+    : game_pieces_sender_(event_loop->MakeSender<GamePieces>("/camera")) {
   event_loop->MakeWatcher("/camera", [this](const CameraImage &camera_image) {
     this->ProcessImage(camera_image);
   });
 }
 
+// TODO(FILIP): Actually do inference.
+
 void GamePiecesDetector::ProcessImage(const CameraImage &image) {
   // Param is not used for now.
   (void)image;
 
+  const int detection_count = 5;
+
   auto builder = game_pieces_sender_.MakeBuilder();
 
-  auto box_builder = builder.MakeBuilder<Box>();
-  box_builder.add_h(10);
-  box_builder.add_w(20);
-  box_builder.add_x(30);
-  box_builder.add_y(40);
-  auto box_offset = box_builder.Finish();
+  std::vector<flatbuffers::Offset<GamePiece>> game_pieces_offsets;
 
-  auto game_piece_builder = builder.MakeBuilder<GamePiece>();
-  game_piece_builder.add_piece_class(y2023::vision::Class::CONE_DOWN);
-  game_piece_builder.add_box(box_offset);
-  game_piece_builder.add_confidence(0.9);
-  auto game_piece = game_piece_builder.Finish();
+  float lowest_distance = std::numeric_limits<float>::max();
+  int best_distance_index = 0;
+  srand(time(0));
+
+  for (int i = 0; i < detection_count; i++) {
+    int h = rand() % 1000;
+    int w = rand() % 1000;
+    int x = rand() % 250;
+    int y = rand() % 250;
+
+    auto box_builder = builder.MakeBuilder<Box>();
+    box_builder.add_h(h);
+    box_builder.add_w(w);
+    box_builder.add_x(x);
+    box_builder.add_y(y);
+    auto box_offset = box_builder.Finish();
+
+    auto game_piece_builder = builder.MakeBuilder<GamePiece>();
+    game_piece_builder.add_piece_class(y2023::vision::Class::CONE_DOWN);
+    game_piece_builder.add_box(box_offset);
+    game_piece_builder.add_confidence(0.9);
+    auto game_piece = game_piece_builder.Finish();
+    game_pieces_offsets.push_back(game_piece);
+
+    // Center x and y values.
+    // Inference returns the top left corner of the bounding box
+    // but we want the center of the box for this.
+
+    const int center_x = x + w / 2;
+    const int center_y = y + h / 2;
+
+    // Find difference between target x, y and the x, y
+    // of the bounding box using Euclidean distance.
+
+    const int dx = FLAGS_best_x - center_x;
+    const int dy = FLAGS_best_y - center_y;
+    const float distance = std::sqrt(dx * dx + dy * dy);
+
+    if (distance < lowest_distance) {
+      lowest_distance = distance;
+      best_distance_index = i;
+    }
+  };
 
   flatbuffers::FlatBufferBuilder fbb;
-  auto game_pieces_vector =
-      fbb.CreateVector(std::vector<flatbuffers::Offset<GamePiece>>{game_piece});
+  auto game_pieces_vector = fbb.CreateVector(game_pieces_offsets);
 
   auto game_pieces_builder = builder.MakeBuilder<GamePieces>();
   game_pieces_builder.add_game_pieces(game_pieces_vector);
+  game_pieces_builder.add_best_piece(best_distance_index);
 
   builder.CheckOk(builder.Send(game_pieces_builder.Finish()));
 }