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, 38 insertions, 0 deletions

diff --git a/source/blender/makesrna/intern/rna_tracking.c b/source/blender/makesrna/intern/rna_tracking.c
index 847efa2fad5..537ffe630a2 100644
--- a/source/blender/makesrna/intern/rna_tracking.c
+++ b/source/blender/makesrna/intern/rna_tracking.c
@@ -372,6 +372,17 @@ static void rna_tracking_stabTracks_active_index_range(PointerRNA *ptr, int *min
 	*max = max_ii(0, clip->tracking.stabilization.tot_track - 1);
 }
 
+static void rna_tracking_resetIntrinsics(Main *UNUSED(bmain), Scene *UNUSED(scene), PointerRNA *ptr)
+{
+	MovieClip *clip = (MovieClip *)ptr->id.data;
+	MovieTracking *tracking = &clip->tracking;
+
+	if (tracking->camera.intrinsics) {
+		BKE_tracking_distortion_free(tracking->camera.intrinsics);
+		tracking->camera.intrinsics = NULL;
+	}
+}
+
 static void rna_tracking_flushUpdate(Main *UNUSED(bmain), Scene *scene, PointerRNA *ptr)
 {
 	MovieClip *clip = (MovieClip *)ptr->id.data;
@@ -990,6 +1001,13 @@ static void rna_def_trackingCamera(BlenderRNA *brna)
 	StructRNA *srna;
 	PropertyRNA *prop;
 
+	static EnumPropertyItem distortion_model_items[] = {
+		{TRACKING_DISTORTION_MODEL_POLYNOMIAL, "POLYNOMIAL", 0, "Polynomial", "Radial distortion model which fits common cameras"},
+		{TRACKING_DISTORTION_MODEL_DIVISION, "DIVISION", 0, "Divisions", "Division distortion model which "
+		                                                                 "better represents wide-angle cameras"},
+		{0, NULL, 0, NULL, NULL}
+	};
+
 	static EnumPropertyItem camera_units_items[] = {
 		{CAMERA_UNITS_PX, "PIXELS", 0, "px", "Use pixels for units of focal length"},
 		{CAMERA_UNITS_MM, "MILLIMETERS", 0, "mm", "Use millimeters for units of focal length"},
@@ -1000,6 +1018,13 @@ static void rna_def_trackingCamera(BlenderRNA *brna)
 	RNA_def_struct_path_func(srna, "rna_trackingCamera_path");
 	RNA_def_struct_ui_text(srna, "Movie tracking camera data", "Match-moving camera data for tracking");
 
+	/* Distortion model */
+	prop = RNA_def_property(srna, "distortion_model", PROP_ENUM, PROP_NONE);
+	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
+	RNA_def_property_enum_items(prop, distortion_model_items);
+	RNA_def_property_ui_text(prop, "Distortion Model", "Distortion model used for camera lenses");
+	RNA_def_property_update(prop, NC_MOVIECLIP | NA_EDITED, "rna_tracking_resetIntrinsics");
+
 	/* Sensor */
 	prop = RNA_def_property(srna, "sensor_width", PROP_FLOAT, PROP_NONE);
 	RNA_def_property_float_sdna(prop, NULL, "sensor_width");
@@ -1065,6 +1090,19 @@ static void rna_def_trackingCamera(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "K3", "Third coefficient of third order polynomial radial distortion");
 	RNA_def_property_update(prop, NC_MOVIECLIP | NA_EDITED, "rna_tracking_flushUpdate");
 
+	/* Division distortion parameters */
+	prop = RNA_def_property(srna, "division_k1", PROP_FLOAT, PROP_NONE);
+	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
+	RNA_def_property_ui_range(prop, -10, 10, 0.1, 3);
+	RNA_def_property_ui_text(prop, "K1", "First coefficient of second order division distortion");
+	RNA_def_property_update(prop, NC_MOVIECLIP | NA_EDITED, "rna_tracking_flushUpdate");
+
+	prop = RNA_def_property(srna, "division_k2", PROP_FLOAT, PROP_NONE);
+	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
+	RNA_def_property_ui_range(prop, -10, 10, 0.1, 3);
+	RNA_def_property_ui_text(prop, "K2", "First coefficient of second order division distortion");
+	RNA_def_property_update(prop, NC_MOVIECLIP | NA_EDITED, "rna_tracking_flushUpdate");
+
 	/* pixel aspect */
 	prop = RNA_def_property(srna, "pixel_aspect", PROP_FLOAT, PROP_XYZ);
 	RNA_def_property_float_sdna(prop, NULL, "pixel_aspect");