From ee5d49dbd39f7313f805cd14221d53d80fbd31ea Mon Sep 17 00:00:00 2001
From: Seebs <seebs@seebs.net>
Date: Fri, 9 Jun 2017 22:22:27 -0500
Subject: [PATCH] Push: Don't convert pixel.RGBA to pixel.RGBA

Because that's expensive, even in the case where the conversion
is trivial. Use type assertion first. Reduces runtime cost of
imdraw.Push from ~15.3% to 8.4%, so not-quite-50% of runtime
cost of pushing points.

If you were setting imd.Color to Color objects that aren't RGBA
every single point, not much help. But if you set it and then
draw a bunch of points, this will be a big win.
---
 imdraw/imdraw.go | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/imdraw/imdraw.go b/imdraw/imdraw.go
index 7f72a4d..e616c39 100644
--- a/imdraw/imdraw.go
+++ b/imdraw/imdraw.go
@@ -128,7 +128,9 @@ func (imd *IMDraw) Draw(t pixel.Target) {
 // Push adds some points to the IM queue. All Pushed points will have the same properties except for
 // the position.
 func (imd *IMDraw) Push(pts ...pixel.Vec) {
-	imd.Color = pixel.ToRGBA(imd.Color)
+	if _, ok := imd.Color.(pixel.RGBA); !ok {
+		imd.Color = pixel.ToRGBA(imd.Color)
+	}
 	opts := point{
 		col:       imd.Color.(pixel.RGBA),
 		pic:       imd.Picture,