Fix T42800: Blender suddenly closes after pressing solve camera motion

Couple of issues:

- Fist/last frame calculation was wrong

- Keyframe selection might silently fail leading to unpredictable math
  errors all over the place. Now if keyframe selection fails solver wouldn't
  run.

1 files changed, 6 insertions, 1 deletions

diff --git a/source/blender/blenkernel/intern/tracking_solver.c b/source/blender/blenkernel/intern/tracking_solver.c
index 6d4e7efa815..d5e2f24e9ed 100644
--- a/source/blender/blenkernel/intern/tracking_solver.c
+++ b/source/blender/blenkernel/intern/tracking_solver.c
@@ -391,7 +391,7 @@ MovieReconstructContext *BKE_tracking_reconstruction_context_new(MovieClip *clip
 			last_marker--;
 		}
 
-		if (first < track->markersnr - 1)
+		if (first <= track->markersnr - 1)
 			sfra = min_ii(sfra, first_marker->framenr);
 
 		if (last >= 0)
@@ -509,6 +509,11 @@ bool BKE_tracking_reconstruction_finish(MovieReconstructContext *context, MovieT
 	MovieTrackingReconstruction *reconstruction;
 	MovieTrackingObject *object;
 
+	if (!libmv_reconstructionIsValid(context->reconstruction)) {
+		printf("Failed solve the motion: most likely there are no good keyframes\n");
+		return false;
+	}
+
 	tracks_map_merge(context->tracks_map, tracking);
 	BKE_tracking_dopesheet_tag_update(tracking);