1 files changed, 29 insertions, 0 deletions
diff --git a/scene/animation/easing_equations.h b/scene/animation/easing_equations.h
index 1b9c378b4f..9150191744 100644
--- a/scene/animation/easing_equations.h
+++ b/scene/animation/easing_equations.h
@@ -413,4 +413,33 @@ static real_t out_in(real_t t, real_t b, real_t c, real_t d) {
 }
 }; // namespace back
 
+namespace spring {
+static real_t out(real_t t, real_t b, real_t c, real_t d) {
+	t /= d;
+	real_t s = 1.0 - t;
+	t = (sin(t * Math_PI * (0.2 + 2.5 * t * t * t)) * pow(s, 2.2) + t) * (1.0 + (1.2 * s));
+	return c * t + b;
+}
+
+static real_t in(real_t t, real_t b, real_t c, real_t d) {
+	return c - out(d - t, 0, c, d) + b;
+}
+
+static real_t in_out(real_t t, real_t b, real_t c, real_t d) {
+	if (t < d / 2) {
+		return in(t * 2, b, c / 2, d);
+	}
+	real_t h = c / 2;
+	return out(t * 2 - d, b + h, h, d);
+}
+
+static real_t out_in(real_t t, real_t b, real_t c, real_t d) {
+	if (t < d / 2) {
+		return out(t * 2, b, c / 2, d);
+	}
+	real_t h = c / 2;
+	return in(t * 2 - d, b + h, h, d);
+}
+}; // namespace spring
+
 #endif // EASING_EQUATIONS_H