Add a special case for 0-time interpolations

2 files changed, 5 insertions, 0 deletions

diff --git a/doc/classes/Tween.xml b/doc/classes/Tween.xml
index ede6e2fdd5..f94018c96b 100644
--- a/doc/classes/Tween.xml
+++ b/doc/classes/Tween.xml
@@ -86,6 +86,7 @@
 				[code]initial_value[/code] is the starting value of the interpolation.
 				[code]delta_value[/code] is the change of the value in the interpolation, i.e. it's equal to [code]final_value - initial_value[/code].
 				[code]duration[/code] is the total time of the interpolation.
+				[b]Note:[/b] If [code]duration[/code] is equal to [code]0[/code], the method will always return the final value, regardless of [code]elapsed_time[/code] provided.
 			</description>
 		</method>
 		<method name="is_running">
diff --git a/thirdparty/misc/easing_equations.cpp b/thirdparty/misc/easing_equations.cpp
index ce32c1a362..d164e3d560 100644
--- a/thirdparty/misc/easing_equations.cpp
+++ b/thirdparty/misc/easing_equations.cpp
@@ -312,6 +312,10 @@ Tween::interpolater Tween::interpolaters[Tween::TRANS_MAX][Tween::EASE_MAX] = {
 };
 
 real_t Tween::run_equation(TransitionType p_trans_type, EaseType p_ease_type, real_t t, real_t b, real_t c, real_t d) {
+	if (d == 0) {
+		// Special case to avoid dividing by 0 in equations.
+		return b + c;
+	}
 
 	interpolater cb = interpolaters[p_trans_type][p_ease_type];
 	ERR_FAIL_COND_V(cb == NULL, b);