Support multiple distortion models, including a new division model

This commit makes it so CameraIntrinsics is no longer hardcoded
to use the traditional polynomial radial distortion model. Currently
the distortion code has generic logic which is shared between
different distortion models, but had no other models until now.

This moves everything specific to the polynomial radial distortion
to a subclass PolynomialDistortionCameraIntrinsics(), and adds a
new division distortion model suitable for cameras such as the
GoPro which have much stronger distortion due to their fisheye lens.

This also cleans up the internal API of CameraIntrinsics to make
it easier to understand and reduces old C-style code.

New distortion model is available in the Lens panel of MCE.

- Polynomial is the old well-known model
- Division is the new one which s intended to deal better with huge
  distortion.

Coefficients of this model works independent from each other
and for division model one probably want to have positive values
to have a barrel distortion.

1 files changed, 67 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/tracking_util.c b/source/blender/blenkernel/intern/tracking_util.c
index 4b3c354dd12..4ebe8494101 100644
--- a/source/blender/blenkernel/intern/tracking_util.c
+++ b/source/blender/blenkernel/intern/tracking_util.c
@@ -51,6 +51,8 @@
 
 #include "tracking_private.h"
 
+#include "libmv-capi.h"
+
 /*********************** Tracks map *************************/
 
 TracksMap *tracks_map_new(const char *object_name, bool is_camera, int num_tracks, int customdata_size)
@@ -386,3 +388,68 @@ void tracking_marker_insert_disabled(MovieTrackingTrack *track, const MovieTrack
 	if (overwrite || !BKE_tracking_track_has_marker_at_frame(track, marker_new.framenr))
 		BKE_tracking_marker_insert(track, &marker_new);
 }
+
+
+/* Fill in Libmv C-API camera intrinsics options from tracking structure.
+ */
+void tracking_cameraIntrinscisOptionsFromTracking(MovieTracking *tracking,
+                                                  int calibration_width, int calibration_height,
+                                                  libmv_CameraIntrinsicsOptions *camera_intrinsics_options)
+{
+	MovieTrackingCamera *camera = &tracking->camera;
+	float aspy = 1.0f / tracking->camera.pixel_aspect;
+
+	camera_intrinsics_options->focal_length = camera->focal;
+
+	camera_intrinsics_options->principal_point_x = camera->principal[0];
+	camera_intrinsics_options->principal_point_y = camera->principal[1] * aspy;
+
+	switch (camera->distortion_model) {
+		case TRACKING_DISTORTION_MODEL_POLYNOMIAL:
+			camera_intrinsics_options->distortion_model = LIBMV_DISTORTION_MODEL_POLYNOMIAL;
+			camera_intrinsics_options->polynomial_k1 = camera->k1;
+			camera_intrinsics_options->polynomial_k2 = camera->k2;
+			camera_intrinsics_options->polynomial_k3 = camera->k3;
+			camera_intrinsics_options->polynomial_p1 = 0.0;
+			camera_intrinsics_options->polynomial_p2 = 0.0;
+			break;
+		case TRACKING_DISTORTION_MODEL_DIVISION:
+			camera_intrinsics_options->distortion_model = LIBMV_DISTORTION_MODEL_DIVISION;
+			camera_intrinsics_options->division_k1 = camera->division_k1;
+			camera_intrinsics_options->division_k2 = camera->division_k2;
+			break;
+		default:
+			BLI_assert(!"Unknown distortion model");
+	}
+
+	camera_intrinsics_options->image_width = calibration_width;
+	camera_intrinsics_options->image_height = (int) (calibration_height * aspy);
+}
+
+void tracking_trackingCameraFromIntrinscisOptions(MovieTracking *tracking,
+                                                  const libmv_CameraIntrinsicsOptions *camera_intrinsics_options)
+{
+	float aspy = 1.0f / tracking->camera.pixel_aspect;
+	MovieTrackingCamera *camera = &tracking->camera;
+
+	camera->focal = camera_intrinsics_options->focal_length;
+
+	camera->principal[0] = camera_intrinsics_options->principal_point_x;
+	camera->principal[1] = camera_intrinsics_options->principal_point_y / (double) aspy;
+
+	switch (camera_intrinsics_options->distortion_model) {
+		case LIBMV_DISTORTION_MODEL_POLYNOMIAL:
+			camera->distortion_model = TRACKING_DISTORTION_MODEL_POLYNOMIAL;
+			camera->k1 = camera_intrinsics_options->polynomial_k1;
+			camera->k2 = camera_intrinsics_options->polynomial_k2;
+			camera->k3 = camera_intrinsics_options->polynomial_k3;
+			break;
+		case LIBMV_DISTORTION_MODEL_DIVISION:
+			camera->distortion_model = TRACKING_DISTORTION_MODEL_DIVISION;
+			camera->division_k1 = camera_intrinsics_options->division_k1;
+			camera->division_k2 = camera_intrinsics_options->division_k2;
+			break;
+		default:
+			BLI_assert(!"Unknown distortion model");
+	}
+}