Frame matching methods for follow track constraint

This is needed in cases when using blender camera with different
resolution than original footage. Behaves in the same way as
background picture framing.

3 files changed, 57 insertions, 3 deletions

diff --git a/source/blender/blenkernel/intern/constraint.c b/source/blender/blenkernel/intern/constraint.c
index e08c9e9d39e..16edbc3f0a9 100644
--- a/source/blender/blenkernel/intern/constraint.c
+++ b/source/blender/blenkernel/intern/constraint.c
@@ -82,8 +82,6 @@
 #include "BKE_tessmesh.h"
 #include "BKE_tracking.h"
 #include "BKE_movieclip.h"
-#include "BKE_tracking.h"
-#include "BKE_movieclip.h"
 
 #ifdef WITH_PYTHON
 #include "BPY_extern.h"
@@ -3985,6 +3983,41 @@ static void followtrack_evaluate(bConstraint *con, bConstraintOb *cob, ListBase
 
 			add_v2_v2v2(pos, marker->pos, track->offset);
 
+			/* aspect correction */
+			if (data->frame_method != FOLLOWTRACK_FRAME_STRETCH) {
+				int width, height;
+				float w_src, h_src, w_dst, h_dst, asp_src, asp_dst;
+
+				BKE_movieclip_get_size(clip, NULL, &width, &height);
+
+				/* apply clip display aspect */
+				w_src = width * clip->aspx;
+				h_src = height * clip->aspy;
+
+				w_dst = scene->r.xsch * scene->r.xasp;
+				h_dst = scene->r.ysch * scene->r.yasp;
+
+				asp_src = w_src / h_src;
+				asp_dst = w_dst / h_dst;
+
+				if (fabsf(asp_src - asp_dst) >= FLT_EPSILON) {
+					if ((asp_src > asp_dst) == (data->frame_method == FOLLOWTRACK_FRAME_CROP)) {
+						/* fit X */
+						float div = asp_src / asp_dst;
+						float cent = (float) width / 2.0f;
+
+						pos[0] = (((pos[0] * width - cent) * div) + cent) / width;
+					}
+					else {
+						/* fit Y */
+						float div = asp_dst / asp_src;
+						float cent = (float) height / 2.0f;
+
+						pos[1] = (((pos[1] * height - cent) * div) + cent) / height;
+					}
+				}
+			}
+
 			BKE_camera_params_init(&params);
 			BKE_camera_params_from_object(&params, camob);
 
diff --git a/source/blender/makesdna/DNA_constraint_types.h b/source/blender/makesdna/DNA_constraint_types.h
index b6036840401..8d953079bdb 100644
--- a/source/blender/makesdna/DNA_constraint_types.h
+++ b/source/blender/makesdna/DNA_constraint_types.h
@@ -415,7 +415,8 @@ typedef struct bShrinkwrapConstraint {
 typedef struct bFollowTrackConstraint {
 	struct MovieClip	*clip;
 	char	track[64];	/* MAX_NAME */
-	int		flag, pad;
+	int		flag;
+	int		frame_method;
 	char		object[64];	/* MAX_NAME */
 	struct Object *camera;
 	struct Object *depth_ob;
@@ -780,6 +781,12 @@ typedef enum eFollowTrack_Flags {
 	FOLLOWTRACK_USE_3D_POSITION	= (1<<1)
 } eFollowTrack_Flags;
 
+typedef enum eFollowTrack_FrameMethod {
+	FOLLOWTRACK_FRAME_STRETCH = 0,
+	FOLLOWTRACK_FRAME_FIT = 1,
+	FOLLOWTRACK_FRAME_CROP = 2
+} eFollowTrack_FrameMethod;
+
 /* CameraSolver Constraint -> flag */
 typedef enum eCameraSolver_Flags {
 	CAMERASOLVER_ACTIVECLIP	= (1<<0)
diff --git a/source/blender/makesrna/intern/rna_constraint.c b/source/blender/makesrna/intern/rna_constraint.c
index 8d718715e5b..770bdb68e38 100644
--- a/source/blender/makesrna/intern/rna_constraint.c
+++ b/source/blender/makesrna/intern/rna_constraint.c
@@ -2207,6 +2207,13 @@ static void rna_def_constraint_follow_track(BlenderRNA *brna)
 	StructRNA *srna;
 	PropertyRNA *prop;
 
+	static const EnumPropertyItem frame_method_items[] = {
+		{FOLLOWTRACK_FRAME_STRETCH, "STRETCH", 0, "Stretch", ""},
+		{FOLLOWTRACK_FRAME_FIT, "FIT", 0, "Fit", ""},
+		{FOLLOWTRACK_FRAME_CROP, "CROP", 0, "Crop", ""},
+		{0, NULL, 0, NULL, NULL}
+	};
+
 	srna = RNA_def_struct(brna, "FollowTrackConstraint", "Constraint");
 	RNA_def_struct_ui_text(srna, "Follow Track Constraint", "Lock motion to the target motion track");
 	RNA_def_struct_sdna_from(srna, "bFollowTrackConstraint", "data");
@@ -2261,6 +2268,13 @@ static void rna_def_constraint_follow_track(BlenderRNA *brna)
 	RNA_def_property_update(prop, NC_OBJECT | ND_CONSTRAINT, "rna_Constraint_dependency_update");
 	RNA_def_property_pointer_funcs(prop, NULL, "rna_Constraint_followTrack_depthObject_set", NULL,
 	                               "rna_Constraint_followTrack_depthObject_poll");
+
+	/* frame method */
+	prop = RNA_def_property(srna, "frame_method", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_bitflag_sdna(prop, NULL, "frame_method");
+	RNA_def_property_enum_items(prop, frame_method_items);
+	RNA_def_property_ui_text(prop, "Frame Method", "How the footage fits in the camera frame");
+	RNA_def_property_update(prop, NC_OBJECT | ND_CONSTRAINT, "rna_Constraint_dependency_update");
 }
 
 static void rna_def_constraint_camera_solver(BlenderRNA *brna)