From 40df98ae2f71ead616cff50def026eeefbea9aab Mon Sep 17 00:00:00 2001
From: Yongwei Xing <yongwei.xing@liulishuo.com>
Date: Fri, 26 Feb 2021 16:13:11 +0800
Subject: [PATCH] add comment

---
 wave.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/wave.go b/wave.go
index f1d69eb..e10640e 100644
--- a/wave.go
+++ b/wave.go
@@ -11,10 +11,12 @@ type wave struct {
 	fn Formula
 }
 
+// NewWave returns a wave generator.
 func NewWave(fn Formula) *wave {
 	return &wave{fn: fn}
 }
 
+// GenerativePolar draws the image in polar coordinator system.
 func (w *wave) GenerativePolar(c *canva, rgba color.RGBA) {
 	for x := -math.Pi; x <= math.Pi; x += 0.01 {
 		for y := -math.Pi; y <= math.Pi; y += 0.01 {
@@ -28,6 +30,7 @@ func (w *wave) GenerativePolar(c *canva, rgba color.RGBA) {
 	}
 }
 
+// Generative draws the image in cartesian coordinator system.
 func (w *wave) Generative(c *canva, rgba color.RGBA) {
 	for x := -math.Pi; x <= math.Pi; x += 0.008 {
 		for y := -math.Pi; y <= math.Pi; y += 0.008 {