first commit

nodes/track/vp_track_node.h

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+
+#pragma once
+
+#include <map>
+#include <assert.h>
+#include "../vp_node.h"
+
+namespace vp_nodes {
+    // track node applied to which type of target (vp_frame_target, vp_frame_face_target or others)
+    enum class vp_track_for {
+        NORMAL = 1,    // vp_frame_target
+        FACE = 2       // vp_frame_face_target
+                       // others to extend
+    };
+
+    // base class for tracking, can not be initialized directly.
+    // note that a track node can work on different channels at the same time
+    class vp_track_node: public vp_node {
+    private:
+        // track for
+        vp_track_for track_for = vp_track_for::NORMAL;
+        
+        // cache tracks at previous frames
+        // std::map<int, std::vector<vp_objects::vp_rect>> tracks_by_id;
+        std::map<int, std::map<int, std::vector<vp_objects::vp_rect>>> all_tracks_by_id;
+
+        // stamp
+        // std::map<int, int> last_tracked_frame_indexes;
+        std::map<int, std::map<int, int>> all_last_tracked_frame_indexes;
+
+        // remove cache tracks if it has been long time since last tracked.
+        const int max_allowed_disappear_frames = 25;
+    protected:
+        virtual std::shared_ptr<vp_objects::vp_meta> handle_frame_meta(std::shared_ptr<vp_objects::vp_frame_meta> meta) override final;
+        virtual std::shared_ptr<vp_objects::vp_meta> handle_control_meta(std::shared_ptr<vp_objects::vp_control_meta> meta) override final;
+
+        // prepare data according to `track_for`
+        void preprocess(std::shared_ptr<vp_objects::vp_frame_meta> frame_meta, 
+                        std::vector<vp_objects::vp_rect>& target_rects, 
+                        std::vector<std::vector<float>>& target_embeddings);
+        
+        // track api
+        // it is a pure virtual function which should be implemented by derived class.
+        // In:  rects & embeddings whose size() can be zero
+        // Out: track ids
+        virtual void track(int channel_index, const std::vector<vp_objects::vp_rect>& target_rects, 
+                        const std::vector<std::vector<float>>& target_embeddings, 
+                        std::vector<int>& track_ids) = 0;
+
+        // write track_ids back to frame meta
+        // we can also cache history rects for each target, and then push them back to tracks field (like vp_frame_target::tracks)
+        void postprocess(std::shared_ptr<vp_objects::vp_frame_meta> frame_meta, 
+                        const std::vector<vp_objects::vp_rect>& target_rects, 
+                        const std::vector<std::vector<float>>& target_embeddings, 
+                        const std::vector<int>& track_ids);
+    public:
+        vp_track_node(std::string node_name, vp_track_for track_for = vp_track_for::NORMAL);
+        virtual ~vp_track_node();
+    };
+}