[GitHub] mlampert commented on a change in pull request #947: Refactor/easing library

[GitBox <gi...@apache.org>]

mlampert commented on a change in pull request #947: Refactor/easing library
URL: https://github.com/apache/mynewt-core/pull/947#discussion_r178365725
 
 

 ##########
 File path: util/easing/src/easing.c
 ##########
 @@ -69,125 +69,128 @@ static inline float quadratic_in(float step, float max_steps, float max_val)
 {
 	float ratio = step / max_steps;
 
-	return max_val * pow(ratio, 2);
+	return max_val * (ratio * ratio);
 }
 
 static inline float quadratic_out(float step, float max_steps, float max_val)
 {
     float ratio = step / max_steps;
 
-	return -max_val * ratio * (ratio - 2.0);
+	return -max_val * ratio * (ratio - 2.0f);
 }
 
 static inline float quadratic_io(float step, float max_steps, float max_val)
 {
-	float ratio = step / (max_steps / 2.0);
+	float ratio = step / (max_steps / 2.0f);
 
 	if (ratio < 1)
-		return max_val / 2.0 * pow(ratio, 2);
+		return max_val / 2.0f * (ratio * ratio);
 
-    ratio = (step - (max_steps/2.0)) / (max_steps/2.0);
-    return (max_val / 2.0) - (max_val / 2.0) * ratio * (ratio - 2.0);
+    ratio = (step - (max_steps/2.0f)) / (max_steps/2.0f);
+    return (max_val / 2.0f) - (max_val / 2.0f) * ratio * (ratio - 2.0f);
 }
 
 /* Cubic */
 static inline float cubic_in(float step, float max_steps, float max_val)
 {
 	float ratio = step / max_steps;
 
-	return max_val * pow(ratio, 3);
+	return max_val * (ratio * ratio * ratio);
 }
 
 static inline float cubic_out(float step, float max_steps, float max_val)
 {
-	float ratio = step / (max_steps - 1.0);
+	float ratio = step / (max_steps - 1.0f);
 
-	return max_val * (pow(ratio, 3) + 1);
+	return max_val * ((ratio * ratio * ratio) + 1);
 }
 
 static inline float cubic_io(float step, float max_steps, float max_val)
 {
-	float ratio = step / (max_steps / 2.0);
+	float ratio = step / (max_steps / 2.0f);
 
 	if (ratio < 1)
-		return max_val / 2 * pow(ratio, 3);
+		return max_val / 2 * (ratio * ratio * ratio);
 
-	return max_val / 2 * (pow(ratio - 2, 3) + 2);
+    ratio -= 2;
+	return max_val / 2 * ((ratio * ratio * ratio) + 2);
 }
 
 /* Quartic */
 static inline float quartic_in(float step, float max_steps, float max_val)
 {
 	float ratio = step / max_steps;
 
-	return max_val * pow(ratio, 4);
+	return max_val * (ratio * ratio * ratio * ratio);
 }
 
 static inline float quartic_out(float step, float max_steps, float max_val)
 {
-	float ratio = (step / max_steps) - 1.0;
+	float ratio = (step / max_steps) - 1.0f;
 
-	return max_val + max_val * pow(ratio, 5);
+	return max_val + max_val * (ratio * ratio * ratio * ratio * ratio);
 }
 
 static inline float quartic_io(float step, float max_steps, float max_val)
 {
-	float ratio = step / (max_steps / 2.0);
+	float ratio = step / (max_steps / 2.0f);
 
 	if (ratio < 1)
-		return max_val / 2 * pow(ratio, 4);
+		return max_val / 2 * (ratio * ratio * ratio * ratio);
 
-	return max_val + max_val / 2 * pow(ratio -2, 5);
+    ratio -= 2;
 
 Review comment:
   the weird identation comes from the original source code having tab characters in some places and github uses tabstop=8. I didn't clean up the tabs because it introduces a lot of noise into the code review but can certainly do that.

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