From ea2b188b64fb89ff51bd9bdf3c958757296afb4c Mon Sep 17 00:00:00 2001
From: Atlante45 <clement.brisset@gmail.com>
Date: Tue, 2 May 2017 17:07:50 -0700
Subject: [PATCH] Recompute Y from X/Z for normal maps

---
 libraries/render-utils/src/MaterialTextures.slh | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/libraries/render-utils/src/MaterialTextures.slh b/libraries/render-utils/src/MaterialTextures.slh
index 7b73896cc5..a530f4faf2 100644
--- a/libraries/render-utils/src/MaterialTextures.slh
+++ b/libraries/render-utils/src/MaterialTextures.slh
@@ -64,7 +64,9 @@ float fetchRoughnessMap(vec2 uv) {
 uniform sampler2D normalMap;
 vec3 fetchNormalMap(vec2 uv) {
     // unpack normal, swizzle to get into hifi tangent space with Y axis pointing out
-    return normalize(texture(normalMap, uv).rbg -vec3(0.5, 0.5, 0.5));
+    vec2 t = 2.0 * (texture(normalMap, uv).rg - vec2(0.5, 0.5));
+    vec2 t2 = t*t;
+    return normalize(vec3(t.x, sqrt(1 - t2.x - t2.y), t.y));
 }
 <@endif@>