GP: New Time modifier

This modifier allows to offset the keyframe animated to get more variations in the animation when reuse the same datablock.

2 files changed, 55 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_gpencil_modifier.h b/source/blender/blenkernel/BKE_gpencil_modifier.h
index cce1d4b0a4a..5efc390015c 100644
--- a/source/blender/blenkernel/BKE_gpencil_modifier.h
+++ b/source/blender/blenkernel/BKE_gpencil_modifier.h
@@ -83,6 +83,8 @@ typedef enum {
 
 	/* can't be added manually by user */
 	eGpencilModifierTypeFlag_NoUserAdd = (1 << 5),
+	/* can't be applied */
+	eGpencilModifierTypeFlag_NoApply = (1 << 6),
 } GpencilModifierTypeFlag;
 
 /* IMPORTANT! Keep ObjectWalkFunc and IDWalkFunc signatures compatible. */
@@ -150,8 +152,18 @@ typedef struct GpencilModifierTypeInfo {
 	void (*bakeModifier)(struct Main *bmain, struct Depsgraph *depsgraph,
                            struct GpencilModifierData *md, struct Object *ob);
 
+
 	/********************* Optional functions *********************/
 
+	/* Callback for GP "time" modifiers that offset keyframe time
+	 * Returns the frame number to be used after apply the modifier. This is
+	 * usually an offset of the animation for duplicated datablocks.
+	 *
+	 * This function is optional.
+	 */
+	int (*remapTime)(struct GpencilModifierData *md, struct Depsgraph *depsgraph,
+		struct Scene *scene, struct Object *ob, struct bGPDlayer *gpl, int cfra);
+
 	/* Initialize new instance data for this modifier type, this function
 	 * should set modifier variables to their default values.
 	 *
@@ -242,6 +254,7 @@ void BKE_gpencil_modifiers_foreachIDLink(struct Object *ob, GreasePencilIDWalkFu
 void BKE_gpencil_modifiers_foreachTexLink(struct Object *ob, GreasePencilTexWalkFunc walk, void *userData);
 
 bool BKE_gpencil_has_geometry_modifiers(struct Object *ob);
+bool BKE_gpencil_has_time_modifiers(struct Object *ob);
 
 void BKE_gpencil_stroke_modifiers(
 	struct Depsgraph *depsgraph, struct Object *ob,
@@ -249,6 +262,9 @@ void BKE_gpencil_stroke_modifiers(
 void BKE_gpencil_geometry_modifiers(
 	struct Depsgraph *depsgraph, struct Object *ob,
 	struct bGPDlayer *gpl, struct bGPDframe *gpf, bool is_render);
+int BKE_gpencil_time_modifier(
+	struct Depsgraph *depsgraph, struct Scene *scene, struct Object *ob,
+	struct bGPDlayer *gpl, int cfra, bool is_render);
 
 void BKE_gpencil_lattice_init(struct Object *ob);
 void BKE_gpencil_lattice_clear(struct Object *ob);
diff --git a/source/blender/blenkernel/intern/gpencil_modifier.c b/source/blender/blenkernel/intern/gpencil_modifier.c
index 1e05a8c271c..d5c1c831c2c 100644
--- a/source/blender/blenkernel/intern/gpencil_modifier.c
+++ b/source/blender/blenkernel/intern/gpencil_modifier.c
@@ -402,6 +402,20 @@ bool BKE_gpencil_has_geometry_modifiers(Object *ob)
 	return false;
 }
 
+/* check if exist time modifiers */
+bool BKE_gpencil_has_time_modifiers(Object *ob)
+{
+	GpencilModifierData *md;
+	for (md = ob->greasepencil_modifiers.first; md; md = md->next) {
+		const GpencilModifierTypeInfo *mti = BKE_gpencil_modifierType_getInfo(md->type);
+
+		if (mti && mti->remapTime) {
+			return true;
+		}
+	}
+	return false;
+}
+
 /* apply stroke modifiers */
 void BKE_gpencil_stroke_modifiers(Depsgraph *depsgraph, Object *ob, bGPDlayer *gpl, bGPDframe *UNUSED(gpf), bGPDstroke *gps, bool is_render)
 {
@@ -459,6 +473,31 @@ void BKE_gpencil_geometry_modifiers(Depsgraph *depsgraph, Object *ob, bGPDlayer
 	}
 }
 
+/* apply time modifiers */
+int BKE_gpencil_time_modifier(Depsgraph *depsgraph, Scene *scene, Object *ob,
+	bGPDlayer *gpl, int cfra, bool is_render)
+{
+	GpencilModifierData *md;
+	bGPdata *gpd = ob->data;
+	const bool is_edit = GPENCIL_ANY_EDIT_MODE(gpd);
+
+	for (md = ob->greasepencil_modifiers.first; md; md = md->next) {
+		if (GPENCIL_MODIFIER_ACTIVE(md, is_render)) {
+			const GpencilModifierTypeInfo *mti = BKE_gpencil_modifierType_getInfo(md->type);
+
+			if (GPENCIL_MODIFIER_EDIT(md, is_edit)) {
+				continue;
+			}
+
+			if (mti->remapTime) {
+				return mti->remapTime(md, depsgraph, scene, ob, gpl, cfra);
+			}
+		}
+	}
+
+	/* if no time modifier, return original frame number */
+	return cfra;
+}
 /* *************************************************** */
 
 void BKE_gpencil_eval_geometry(Depsgraph *depsgraph,