[Bf-blender-cvs] [13ce25d24c9] master: Tracking: Clarify tracks and options storage once again

[Sergey Sharybin]

Commit: 13ce25d24c9d667282784f34fd5e5e875b350c91
Author: Sergey Sharybin
Date:   Mon Nov 30 16:14:06 2020 +0100
Branches: master
https://developer.blender.org/rB13ce25d24c9d667282784f34fd5e5e875b350c91

Tracking: Clarify tracks and options storage once again

This is something not-so-trivial to see from just reading code, which
shown an important of proper comments and clear naming.

Main source of confusion was that it is not immediately clear that
AutoTrack context is to see all tracks, but tracking to only operate on
selected ones.

===================================================================

M	source/blender/blenkernel/intern/tracking_auto.c

===================================================================

diff --git a/source/blender/blenkernel/intern/tracking_auto.c b/source/blender/blenkernel/intern/tracking_auto.c
index d49d6779d64..edd798b162a 100644
--- a/source/blender/blenkernel/intern/tracking_auto.c
+++ b/source/blender/blenkernel/intern/tracking_auto.c
@@ -76,19 +76,13 @@ typedef struct AutoTrackContext {
   MovieClip *clips[MAX_ACCESSOR_CLIP];
 
   /* Tracks for which the context has been created for.
-   * Most usually this is all track selected in the interface when tracking in initialized.
-   *
-   * NOTE: Actually being-tracked tracks is a subset of those, as the tracker might loose track of
-   * where markers are. For example, if feature gets occluded, corresponding marker can not be
-   * tracked, and hence track is considered finished.
-   *
-   * The need of knowledge of all tracks which might potentially be modified during tracking comes
-   * form plane tracks: plane tracks needs adjustment if any of their tracks changed during
-   * tracking.
+   * This is a flat array of all tracks coming from all clips, regardless of whether track is
+   * actually being tracked or not. This allows the AutoTrack to see a big picture of hat is going
+   * on in the scene, and request information it needs.
    *
    * Indexed by AutoTrackOptions::track_index. */
-  int num_input_tracks;
-  MovieTrackingTrack **input_tracks;
+  int num_all_tracks;
+  MovieTrackingTrack **all_tracks;
 
   /* Dimensions of movie frame, in pixels.
    *
@@ -107,6 +101,7 @@ typedef struct AutoTrackContext {
    * NOTE: Is accessed from multiple threads at once. */
   struct libmv_AutoTrack *autotrack;
 
+  int num_track_options;
   AutoTrackOptions *track_options; /* Per-tracking track options. */
 
   int sync_frame;
@@ -340,15 +335,17 @@ static void create_per_track_tracking_options(const MovieClip *clip,
   /* Count number of trackable tracks. */
   LISTBASE_FOREACH (MovieTrackingTrack *, track, tracksbase) {
     if (check_track_trackable(clip, track, user)) {
-      context->num_input_tracks++;
+      context->num_track_options++;
     }
   }
   /* Allocate required memory. */
-  context->track_options = MEM_callocN(sizeof(AutoTrackOptions) * context->num_input_tracks,
+  context->track_options = MEM_callocN(sizeof(AutoTrackOptions) * context->num_track_options,
                                        "auto track options");
   /* Fill in all the settings. */
   int i = 0, track_index = 0;
   LISTBASE_FOREACH (MovieTrackingTrack *, track, tracksbase) {
+    context->all_tracks[track_index] = track;
+
     if (!check_track_trackable(clip, track, user)) {
       track_index++;
       continue;
@@ -364,7 +361,6 @@ static void create_per_track_tracking_options(const MovieClip *clip,
 
     tracking_configure_tracker(track, NULL, &track_options->track_region_options);
 
-    context->input_tracks[track_index] = track;
     track_index++;
   }
 }
@@ -390,19 +386,19 @@ AutoTrackContext *BKE_autotrack_context_new(MovieClip *clip,
   context->sync_frame = user->framenr;
   context->first_sync = true;
   BLI_spin_init(&context->spin_lock);
-  const int num_total_tracks = BLI_listbase_count(tracksbase);
-  context->input_tracks = MEM_callocN(sizeof(MovieTrackingTrack *) * num_total_tracks,
-                                      "auto track pointers");
+  context->num_all_tracks = BLI_listbase_count(tracksbase);
+  context->all_tracks = MEM_callocN(sizeof(MovieTrackingTrack *) * context->num_all_tracks,
+                                    "auto track pointers");
+  /* Create per-track tracking options. */
+  create_per_track_tracking_options(clip, user, tracksbase, context);
   /* Initialize image accessor. */
   context->image_accessor = tracking_image_accessor_new(
-      context->clips, 1, context->input_tracks, num_total_tracks);
+      context->clips, 1, context->all_tracks, context->num_all_tracks);
   /* Initialize auto track context and provide all information about currently
    * tracked markers.
    */
   context->autotrack = libmv_autoTrackNew(context->image_accessor->libmv_accessor);
   fill_autotrack_tracks(frame_width, frame_height, tracksbase, is_backwards, context->autotrack);
-  /* Create per-track tracking options. */
-  create_per_track_tracking_options(clip, user, tracksbase, context);
   return context;
 }
 
@@ -485,9 +481,9 @@ bool BKE_autotrack_context_step(AutoTrackContext *context)
 
   TaskParallelSettings settings;
   BLI_parallel_range_settings_defaults(&settings);
-  settings.use_threading = (context->num_input_tracks > 1);
+  settings.use_threading = (context->num_track_options > 1);
   BLI_task_parallel_range(
-      0, context->num_input_tracks, context, autotrack_context_step_cb, &settings);
+      0, context->num_track_options, context, autotrack_context_step_cb, &settings);
 
   /* Advance the frame. */
   BLI_spin_lock(&context->spin_lock);
@@ -508,7 +504,7 @@ void BKE_autotrack_context_sync(AutoTrackContext *context)
     MovieTrackingMarker marker;
     libmv_Marker libmv_marker;
     int clip = 0;
-    for (int i = 0; i < context->num_input_tracks; i++) {
+    for (int i = 0; i < context->num_track_options; i++) {
       AutoTrackOptions *track_options = &context->track_options[i];
       MovieTrackingTrack *track = track_options->track;
       const int clip_index = track_options->clip_index;
@@ -574,7 +570,7 @@ void BKE_autotrack_context_finish(AutoTrackContext *context)
       if ((plane_track->flag & PLANE_TRACK_AUTOKEY)) {
         continue;
       }
-      for (int i = 0; i < context->num_input_tracks; i++) {
+      for (int i = 0; i < context->num_track_options; i++) {
         const AutoTrackOptions *track_options = &context->track_options[i];
         MovieTrackingTrack *track = track_options->track;
         if (BKE_tracking_plane_track_has_point_track(plane_track, track)) {
@@ -591,7 +587,7 @@ void BKE_autotrack_context_free(AutoTrackContext *context)
   libmv_autoTrackDestroy(context->autotrack);
   tracking_image_accessor_destroy(context->image_accessor);
   MEM_freeN(context->track_options);
-  MEM_freeN(context->input_tracks);
+  MEM_freeN(context->all_tracks);
   BLI_spin_end(&context->spin_lock);
   MEM_freeN(context);
 }