GDScript: Clarified/fixed inaccuracies in the built-in function docs.

The input to smoothstep is not actually a weight, and the decscription
of smoothstep was pretty hard to understand and easy to misinterpret.

Clarified what it means to be approximately equal.

nearest_po2 does not do what the descriptions says it does. For one,
it returns the same power if the input is a power of 2. Second, it
returns 0 if the input is negative or 0, while the smallest possible
integral power of 2 actually is 1 (2^0 = 1). Due to the implementation
and how it is used in a lot of places, it does not seem wise to change
such a core function however, and I decided it is better to alter the
description of the built-in.

Added a few examples/clarifications/edge-cases.

1 files changed, 6 insertions, 6 deletions

diff --git a/core/math/math_funcs.h b/core/math/math_funcs.h
index 7a9fd60e23..9f8d4da5b3 100644
--- a/core/math/math_funcs.h
+++ b/core/math/math_funcs.h
@@ -231,19 +231,19 @@ public:
 	static _ALWAYS_INLINE_ double range_lerp(double p_value, double p_istart, double p_istop, double p_ostart, double p_ostop) { return Math::lerp(p_ostart, p_ostop, Math::inverse_lerp(p_istart, p_istop, p_value)); }
 	static _ALWAYS_INLINE_ float range_lerp(float p_value, float p_istart, float p_istop, float p_ostart, float p_ostop) { return Math::lerp(p_ostart, p_ostop, Math::inverse_lerp(p_istart, p_istop, p_value)); }
 
-	static _ALWAYS_INLINE_ double smoothstep(double p_from, double p_to, double p_weight) {
+	static _ALWAYS_INLINE_ double smoothstep(double p_from, double p_to, double p_s) {
 		if (is_equal_approx(p_from, p_to)) {
 			return p_from;
 		}
-		double x = CLAMP((p_weight - p_from) / (p_to - p_from), 0.0, 1.0);
-		return x * x * (3.0 - 2.0 * x);
+		double s = CLAMP((p_s - p_from) / (p_to - p_from), 0.0, 1.0);
+		return s * s * (3.0 - 2.0 * s);
 	}
-	static _ALWAYS_INLINE_ float smoothstep(float p_from, float p_to, float p_weight) {
+	static _ALWAYS_INLINE_ float smoothstep(float p_from, float p_to, float p_s) {
 		if (is_equal_approx(p_from, p_to)) {
 			return p_from;
 		}
-		float x = CLAMP((p_weight - p_from) / (p_to - p_from), 0.0f, 1.0f);
-		return x * x * (3.0f - 2.0f * x);
+		float s = CLAMP((p_s - p_from) / (p_to - p_from), 0.0f, 1.0f);
+		return s * s * (3.0f - 2.0f * s);
 	}
 	static _ALWAYS_INLINE_ double move_toward(double p_from, double p_to, double p_delta) { return abs(p_to - p_from) <= p_delta ? p_to : p_from + SGN(p_to - p_from) * p_delta; }
 	static _ALWAYS_INLINE_ float move_toward(float p_from, float p_to, float p_delta) { return abs(p_to - p_from) <= p_delta ? p_to : p_from + SGN(p_to - p_from) * p_delta; }