From 7215265523612fdda6a2429b7409f9da76a83f76 Mon Sep 17 00:00:00 2001
From: Seebs <seebs@seebs.net>
Date: Fri, 9 Jun 2017 00:07:08 -0500
Subject: [PATCH] Don't duplicate computations in gltriangles.go
The computation including a call to Stride() can't be optimized away
safely because the compiler can't tell that Stride() is effectively
constant, but we know it won't change so we can make a slice pointing
at that part of the array.
CPU time for updateData goes from 26.35% to 18.65% in my test case.
---
pixelgl/gltriangles.go | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)
diff --git a/pixelgl/gltriangles.go b/pixelgl/gltriangles.go
index 64b7355..bf7a895 100644
--- a/pixelgl/gltriangles.go
+++ b/pixelgl/gltriangles.go
@@ -103,15 +103,17 @@ func (gt *GLTriangles) updateData(t pixel.Triangles) {
tx, ty = (*t)[i].Picture.XY()
in = (*t)[i].Intensity
)
- gt.data[i*gt.vs.Stride()+0] = float32(px)
- gt.data[i*gt.vs.Stride()+1] = float32(py)
- gt.data[i*gt.vs.Stride()+2] = float32(col.R)
- gt.data[i*gt.vs.Stride()+3] = float32(col.G)
- gt.data[i*gt.vs.Stride()+4] = float32(col.B)
- gt.data[i*gt.vs.Stride()+5] = float32(col.A)
- gt.data[i*gt.vs.Stride()+6] = float32(tx)
- gt.data[i*gt.vs.Stride()+7] = float32(ty)
- gt.data[i*gt.vs.Stride()+8] = float32(in)
+ s := gt.vs.Stride()
+ d := gt.data[i*s : i*s+9]
+ d[0] = float32(px)
+ d[1] = float32(py)
+ d[2] = float32(col.R)
+ d[3] = float32(col.G)
+ d[4] = float32(col.B)
+ d[5] = float32(col.A)
+ d[6] = float32(tx)
+ d[7] = float32(ty)
+ d[8] = float32(in)
}
return
}
--
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