Patch T22084: Robert Penner Easing Equations for FCurves

This commit introduces support for a number of new interpolation types
which are useful for motion-graphics work. These define a number of
"easing equations" (basically, equations which define some preset
ways that one keyframe transitions to another) which reduce the amount
of manual work (inserting and tweaking keyframes) to achieve certain
common effects. For example, snappy movements, and fake-physics such
as bouncing/springing effects.

The additional interpolation types introduced in this commit can be found
in many packages and toolkits (notably Qt and all modern web browsers).
For more info and a few live demos, see [1] and [2].


Credits:
* Dan Eicher (dna)              - Original patch
* Thomas Beck (plasmasolutions) - Porting/updating patch to 2.70 codebase
* Joshua Leung (aligorith)      - Code review and a few polishing tweaks

Additional Resources:
[1] http://easings.net
[2] http://www.robertpenner.com/easing/

7 files changed, 228 insertions, 3 deletions

diff --git a/source/blender/editors/animation/keyframes_edit.c b/source/blender/editors/animation/keyframes_edit.c
index 6b294c93b42..b14bbe821e8 100644
--- a/source/blender/editors/animation/keyframes_edit.c
+++ b/source/blender/editors/animation/keyframes_edit.c
@@ -922,15 +922,109 @@ static short set_bezt_bezier(KeyframeEditData *UNUSED(ked), BezTriple *bezt)
 	return 0;
 }
 
+static short set_bezt_back(KeyframeEditData *UNUSED(ked), BezTriple *bezt)
+{
+	if (bezt->f2 & SELECT)
+		bezt->ipo = BEZT_IPO_BACK;
+	return 0;
+}
+
+static short set_bezt_bounce(KeyframeEditData *UNUSED(ked), BezTriple *bezt)
+{
+	if (bezt->f2 & SELECT)
+		bezt->ipo = BEZT_IPO_BOUNCE;
+	return 0;
+}
+
+static short set_bezt_circle(KeyframeEditData *UNUSED(ked), BezTriple *bezt)
+{
+	if (bezt->f2 & SELECT)
+		bezt->ipo = BEZT_IPO_CIRC;
+	return 0;
+}
+
+static short set_bezt_cubic(KeyframeEditData *UNUSED(ked), BezTriple *bezt)
+{
+	if (bezt->f2 & SELECT)
+		bezt->ipo = BEZT_IPO_CUBIC;
+	return 0;
+}
+
+static short set_bezt_elastic(KeyframeEditData *UNUSED(ked), BezTriple *bezt)
+{
+	if (bezt->f2 & SELECT)
+		bezt->ipo = BEZT_IPO_ELASTIC;
+	return 0;
+}
+
+static short set_bezt_expo(KeyframeEditData *UNUSED(ked), BezTriple *bezt)
+{
+	if (bezt->f2 & SELECT)
+		bezt->ipo = BEZT_IPO_EXPO;
+	return 0;
+}
+
+static short set_bezt_quad(KeyframeEditData *UNUSED(ked), BezTriple *bezt)
+{
+	if (bezt->f2 & SELECT)
+		bezt->ipo = BEZT_IPO_QUAD;
+	return 0;
+}
+
+static short set_bezt_quart(KeyframeEditData *UNUSED(ked), BezTriple *bezt)
+{
+	if (bezt->f2 & SELECT)
+		bezt->ipo = BEZT_IPO_QUART;
+	return 0;
+}
+
+static short set_bezt_quint(KeyframeEditData *UNUSED(ked), BezTriple *bezt)
+{
+	if (bezt->f2 & SELECT)
+		bezt->ipo = BEZT_IPO_QUINT;
+	return 0;
+}
+
+static short set_bezt_sine(KeyframeEditData *UNUSED(ked), BezTriple *bezt)
+{
+	if (bezt->f2 & SELECT)
+		bezt->ipo= BEZT_IPO_SINE;
+	return 0;
+}
+
 /* Set the interpolation type of the selected BezTriples in each F-Curve to the specified one */
 // ANIM_editkeyframes_ipocurve_ipotype() !
 KeyframeEditFunc ANIM_editkeyframes_ipo(short code)
 {
 	switch (code) {
+		/* interpolation */
 		case BEZT_IPO_CONST: /* constant */
 			return set_bezt_constant;
 		case BEZT_IPO_LIN: /* linear */
 			return set_bezt_linear;
+			
+		/* easing */
+		case BEZT_IPO_BACK:
+			return set_bezt_back;
+		case BEZT_IPO_BOUNCE:
+			return set_bezt_bounce;
+		case BEZT_IPO_CIRC:
+			return set_bezt_circle;
+		case BEZT_IPO_CUBIC:
+			return set_bezt_cubic;
+		case BEZT_IPO_ELASTIC:
+			return set_bezt_elastic;
+		case BEZT_IPO_EXPO:
+			return set_bezt_expo;
+		case BEZT_IPO_QUAD:
+			return set_bezt_quad;
+		case BEZT_IPO_QUART:
+			return set_bezt_quart;
+		case BEZT_IPO_QUINT:
+			return set_bezt_quint;
+		case BEZT_IPO_SINE:
+			return set_bezt_sine;
+			
 		default: /* bezier */
 			return set_bezt_bezier;
 	}
@@ -985,6 +1079,45 @@ KeyframeEditFunc ANIM_editkeyframes_keytype(short code)
 	}
 }
 
+/* ------- */
+
+static short set_easingtype_easein(KeyframeEditData *UNUSED(ked), BezTriple *bezt)
+{
+	if (bezt->f2 & SELECT)
+		bezt->easing = BEZT_IPO_EASE_IN;
+	return 0;
+}
+
+static short set_easingtype_easeout(KeyframeEditData *UNUSED(ked), BezTriple *bezt)
+{
+	if (bezt->f2 & SELECT)
+		bezt->easing = BEZT_IPO_EASE_OUT;
+	return 0;
+}
+
+static short set_easingtype_easeinout(KeyframeEditData *UNUSED(ked), BezTriple *bezt)
+{
+	if (bezt->f2 & SELECT)
+		bezt->easing = BEZT_IPO_EASE_IN_OUT;
+	return 0;
+}
+
+/* Set the easing type of the selected BezTriples in each F-Curve to the specified one */
+KeyframeEditFunc ANIM_editkeyframes_easing(short mode)
+{
+	switch (mode) {
+		case BEZT_IPO_EASE_IN: /* ease in */
+			return set_easingtype_easein;
+		
+		case BEZT_IPO_EASE_OUT: /* ease out */
+			return set_easingtype_easeout;
+		
+		case BEZT_IPO_EASE_IN_OUT: /* both */
+		default:
+			return set_easingtype_easeinout;
+	}
+}
+
 /* ******************************************* */
 /* Selection */
 
diff --git a/source/blender/editors/include/ED_keyframes_edit.h b/source/blender/editors/include/ED_keyframes_edit.h
index 4e68b6a9494..c8365689803 100644
--- a/source/blender/editors/include/ED_keyframes_edit.h
+++ b/source/blender/editors/include/ED_keyframes_edit.h
@@ -217,6 +217,7 @@ KeyframeEditFunc ANIM_editkeyframes_select(short mode);
 KeyframeEditFunc ANIM_editkeyframes_handles(short mode);
 KeyframeEditFunc ANIM_editkeyframes_ipo(short mode);
 KeyframeEditFunc ANIM_editkeyframes_keytype(short mode);
+KeyframeEditFunc ANIM_editkeyframes_easing(short mode);
 
 /* -------- BezTriple Callbacks (Selection Map) ---------- */
 
diff --git a/source/blender/editors/space_graph/graph_buttons.c b/source/blender/editors/space_graph/graph_buttons.c
index 42aa9935251..671a4c3afd3 100644
--- a/source/blender/editors/space_graph/graph_buttons.c
+++ b/source/blender/editors/space_graph/graph_buttons.c
@@ -291,7 +291,26 @@ static void graph_panel_key_properties(const bContext *C, Panel *pa)
 		/* interpolation */
 		col = uiLayoutColumn(layout, FALSE);
 		uiItemR(col, &bezt_ptr, "interpolation", 0, NULL, ICON_NONE);
-			
+		
+		/* easing type */
+		if (bezt->ipo > BEZT_IPO_BEZ)
+			uiItemR(col, &bezt_ptr, "easing", 0, NULL, 0);
+
+		/* easing extra */
+		switch (bezt->ipo) {
+			case BEZT_IPO_BACK:
+				col = uiLayoutColumn(layout, 1);
+				uiItemR(col, &bezt_ptr, "back", 0, NULL, 0);
+				break;
+			case BEZT_IPO_ELASTIC:
+				col = uiLayoutColumn(layout, 1);
+				uiItemR(col, &bezt_ptr, "amplitude", 0, NULL, 0);
+				uiItemR(col, &bezt_ptr, "period", 0, NULL, 0);
+				break;
+			default:
+				break;
+		}
+		
 		/* numerical coordinate editing 
 		 *  - we use the button-versions of the calls so that we can attach special update handlers
 		 *    and unit conversion magic that cannot be achieved using a purely RNA-approach
diff --git a/source/blender/editors/space_graph/graph_draw.c b/source/blender/editors/space_graph/graph_draw.c
index ab69dc9e7b9..eb36abe6eef 100644
--- a/source/blender/editors/space_graph/graph_draw.c
+++ b/source/blender/editors/space_graph/graph_draw.c
@@ -623,6 +623,7 @@ static void draw_fcurve_curve_samples(bAnimContext *ac, ID *id, FCurve *fcu, Vie
 	glPopMatrix();
 }
 
+#if 0
 /* helper func - draw one repeat of an F-Curve */
 static void draw_fcurve_curve_bezts(bAnimContext *ac, ID *id, FCurve *fcu, View2D *v2d)
 {
@@ -778,7 +779,8 @@ static void draw_fcurve_curve_bezts(bAnimContext *ac, ID *id, FCurve *fcu, View2
 	
 	glEnd();
 	glPopMatrix();
-} 
+}
+#endif
 
 /* Debugging -------------------------------- */
 
@@ -995,7 +997,8 @@ void graph_draw_curves(bAnimContext *ac, SpaceIpo *sipo, ARegion *ar, View2DGrid
 			else if (((fcu->bezt) || (fcu->fpt)) && (fcu->totvert)) {
 				/* just draw curve based on defined data (i.e. no modifiers) */
 				if (fcu->bezt)
-					draw_fcurve_curve_bezts(ac, ale->id, fcu, &ar->v2d);
+					//draw_fcurve_curve_bezts(ac, ale->id, fcu, &ar->v2d);
+					draw_fcurve_curve(ac, ale->id, fcu, &ar->v2d, grid);  // XXX: better to do an optimised integration here instead, but for now, this works
 				else if (fcu->fpt)
 					draw_fcurve_curve_samples(ac, ale->id, fcu, &ar->v2d);
 			}
diff --git a/source/blender/editors/space_graph/graph_edit.c b/source/blender/editors/space_graph/graph_edit.c
index 93d103e11a6..0fa6edd0011 100644
--- a/source/blender/editors/space_graph/graph_edit.c
+++ b/source/blender/editors/space_graph/graph_edit.c
@@ -1502,6 +1502,72 @@ void GRAPH_OT_interpolation_type(wmOperatorType *ot)
 	ot->prop = RNA_def_enum(ot->srna, "type", beztriple_interpolation_mode_items, 0, "Type", "");
 }
 
+/* ******************** Set Easing Operator *********************** */
+
+static void seteasing_graph_keys(bAnimContext *ac, short mode)
+{
+	ListBase anim_data = {NULL, NULL};
+	bAnimListElem *ale;
+	int filter;
+	KeyframeEditFunc set_cb = ANIM_editkeyframes_easing(mode);
+	
+	/* filter data */
+	filter = (ANIMFILTER_DATA_VISIBLE | ANIMFILTER_CURVE_VISIBLE | ANIMFILTER_FOREDIT | ANIMFILTER_NODUPLIS);
+	ANIM_animdata_filter(ac, &anim_data, filter, ac->data, ac->datatype);
+	
+	/* loop through setting BezTriple easing
+	 * Note: we do not supply KeyframeEditData to the looper yet. Currently that's not necessary here...
+	 */
+	for (ale = anim_data.first; ale; ale = ale->next)
+		ANIM_fcurve_keyframes_loop(NULL, ale->key_data, NULL, set_cb, calchandles_fcurve);
+	
+	/* cleanup */
+	BLI_freelistN(&anim_data);
+}
+
+static int graphkeys_easing_exec(bContext *C, wmOperator *op)
+{
+	bAnimContext ac;
+	short mode;
+	
+	/* get editor data */
+	if (ANIM_animdata_get_context(C, &ac) == 0)
+		return OPERATOR_CANCELLED;
+	
+	/* get handle setting mode */
+	mode = RNA_enum_get(op->ptr, "type");
+	
+	/* set handle type */
+	seteasing_graph_keys(&ac, mode);
+	
+	/* validate keyframes after editing */
+	ANIM_editkeyframes_refresh(&ac);
+	
+	/* set notifier that keyframe properties have changed */
+	WM_event_add_notifier(C, NC_ANIMATION | ND_KEYFRAME_PROP, NULL);
+	
+	return OPERATOR_FINISHED;
+}
+
+void GRAPH_OT_easing_type(wmOperatorType *ot)
+{
+	/* identifiers */
+	ot->name = "Set Keyframe Easing Type";
+	ot->idname = "GRAPH_OT_easing_type";
+	ot->description = "Set easing type for the F-Curve segments starting from the selected keyframes";
+	
+	/* api callbacks */
+	ot->invoke = WM_menu_invoke;
+	ot->exec = graphkeys_easing_exec;
+	ot->poll = graphop_editable_keyframes_poll;
+	
+	/* flags */
+	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
+	
+	/* id-props */
+	ot->prop = RNA_def_enum(ot->srna, "type", beztriple_interpolation_easing_items, 0, "Type", "");
+}
+
 /* ******************** Set Handle-Type Operator *********************** */
 
 /* this function is responsible for setting handle-type of selected keyframes */
diff --git a/source/blender/editors/space_graph/graph_intern.h b/source/blender/editors/space_graph/graph_intern.h
index 567b0a60bb0..fe1378679d8 100644
--- a/source/blender/editors/space_graph/graph_intern.h
+++ b/source/blender/editors/space_graph/graph_intern.h
@@ -112,6 +112,7 @@ void GRAPH_OT_euler_filter(struct wmOperatorType *ot);
 void GRAPH_OT_handle_type(struct wmOperatorType *ot);
 void GRAPH_OT_interpolation_type(struct wmOperatorType *ot);
 void GRAPH_OT_extrapolation_type(struct wmOperatorType *ot);
+void GRAPH_OT_easing_type(struct wmOperatorType *ot);
 
 void GRAPH_OT_frame_jump(struct wmOperatorType *ot);
 void GRAPH_OT_snap(struct wmOperatorType *ot);
diff --git a/source/blender/editors/space_graph/graph_ops.c b/source/blender/editors/space_graph/graph_ops.c
index 0b9936ff14e..1041c885697 100644
--- a/source/blender/editors/space_graph/graph_ops.c
+++ b/source/blender/editors/space_graph/graph_ops.c
@@ -227,6 +227,7 @@ void graphedit_operatortypes(void)
 	WM_operatortype_append(GRAPH_OT_handle_type);
 	WM_operatortype_append(GRAPH_OT_interpolation_type);
 	WM_operatortype_append(GRAPH_OT_extrapolation_type);
+	WM_operatortype_append(GRAPH_OT_easing_type);
 	WM_operatortype_append(GRAPH_OT_sample);
 	WM_operatortype_append(GRAPH_OT_bake);
 	WM_operatortype_append(GRAPH_OT_sound_bake);
@@ -376,6 +377,7 @@ static void graphedit_keymap_keyframes(wmKeyConfig *keyconf, wmKeyMap *keymap)
 	WM_keymap_add_item(keymap, "GRAPH_OT_handle_type", VKEY, KM_PRESS, 0, 0);
 
 	WM_keymap_add_item(keymap, "GRAPH_OT_interpolation_type", TKEY, KM_PRESS, 0, 0);
+	WM_keymap_add_item(keymap, "GRAPH_OT_easing_type", EKEY, KM_PRESS, KM_CTRL, 0);
 	
 	/* destructive */
 	WM_keymap_add_item(keymap, "GRAPH_OT_clean", OKEY, KM_PRESS, 0, 0);