From c6e7a834679b85a464b2f1617280f600d0fdf61c Mon Sep 17 00:00:00 2001
From: Seebs <seebs@seebs.net>
Date: Mon, 5 Jun 2017 20:12:35 -0500
Subject: [PATCH] Reduce copying in fillPolygon

A slice of points means copying every point into the slice, then
copying every point's data from the slice to TrianglesData. An
array of indicies lets the compiler make better choices.
---
 imdraw/imdraw.go | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/imdraw/imdraw.go b/imdraw/imdraw.go
index 0d40452..e5a8c95 100644
--- a/imdraw/imdraw.go
+++ b/imdraw/imdraw.go
@@ -354,11 +354,12 @@ func (imd *IMDraw) fillPolygon() {
 	imd.tri.SetLen(imd.tri.Len() + 3*(len(points)-2))
 
 	for i, j := 1, off; i+1 < len(points); i, j = i+1, j+3 {
-		for k, p := range []point{points[0], points[i], points[i+1]} {
-			(*imd.tri)[j+k].Position = p.pos
-			(*imd.tri)[j+k].Color = p.col
-			(*imd.tri)[j+k].Picture = p.pic
-			(*imd.tri)[j+k].Intensity = p.in
+		for k, p := range []int{0, i, i + 1} {
+			tri := &(*imd.tri)[j+k]
+			tri.Position = points[p].pos
+			tri.Color = points[p].col
+			tri.Picture = points[p].pic
+			tri.Intensity = points[p].in
 		}
 	}