Save per-fragment normalization by doing it CPU side once when set

The spot light local direction was being normalized in the fragment
shader which is a lot of work. Much better to normalize it once on the
CPU side when it is updated.

Change-Id: I87045462b6b09fad4262f5755493b87595d29f11
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/src/render/lights/qspotlight.cpp b/src/render/lights/qspotlight.cpp
index 54ed8da63..81c18387b 100644
--- a/src/render/lights/qspotlight.cpp
+++ b/src/render/lights/qspotlight.cpp
@@ -221,8 +221,9 @@ void QSpotLight::setLocalDirection(const QVector3D &direction)
 {
     Q_D(QSpotLight);
     if (localDirection() != direction) {
-        d->m_shaderData->setProperty("direction", direction);
-        emit localDirectionChanged(direction);
+        const QVector3D dir = direction.normalized();
+        d->m_shaderData->setProperty("direction", dir);
+        emit localDirectionChanged(dir);
     }
 }