From 50621aec50fdc78536222890af1934f9b0651fc0 Mon Sep 17 00:00:00 2001
From: Ryan Oldenburg <ryan@guzba.com>
Date: Sun, 28 Nov 2021 03:08:25 -0600
Subject: [PATCH] faster packAlphaValues, better test

---
 src/pixie/internal.nim | 19 ++++---------------
 tests/test_images.nim  |  2 +-
 2 files changed, 5 insertions(+), 16 deletions(-)

diff --git a/src/pixie/internal.nim b/src/pixie/internal.nim
index c46af28..4a19cf1 100644
--- a/src/pixie/internal.nim
+++ b/src/pixie/internal.nim
@@ -105,18 +105,7 @@ when defined(amd64) and not defined(pixieNoSimd):
 
   proc unpackAlphaValues*(v: M128i): M128i {.inline, raises: [].} =
     ## Unpack the first 32 bits into 4 rgba(0, 0, 0, value)
-    let mask = cast[M128i]([uint8.high.uint64, 0])
-
-    var
-      i = mm_and_si128(v, mask)
-      j = mm_and_si128(v, mm_slli_si128(mask, 1))
-      k = mm_and_si128(v, mm_slli_si128(mask, 2))
-      l = mm_and_si128(v, mm_slli_si128(mask, 3))
-
-    # Shift the values to uint32 `a`
-    i = mm_slli_si128(i, 3)
-    j = mm_slli_si128(j, 6)
-    k = mm_slli_si128(k, 9)
-    l = mm_slli_si128(l, 12)
-
-    result = mm_or_si128(mm_or_si128(i, j), mm_or_si128(k, l))
+    let
+      a = mm_unpacklo_epi8(v, mm_setzero_si128())
+      b = mm_unpacklo_epi8(a, mm_setzero_si128())
+    result = mm_slli_epi32(b, 24) # Shift the values to uint32 `a`
diff --git a/tests/test_images.nim b/tests/test_images.nim
index 8d5ad7e..2e471d7 100644
--- a/tests/test_images.nim
+++ b/tests/test_images.nim
@@ -145,7 +145,7 @@ block: # Test conversion between image and mask
     originalMask = newMask(100, 100)
 
   let p = newPath()
-  p.rect(10, 10, 80, 80)
+  p.circle(50, 50, 25)
 
   originalImage.fillPath(p, rgba(255, 0, 0, 255))
   originalMask.fillPath(p)