Add attenuation factors for point lights

For decent results the distance and the attenuation factors will have
to be taken into account.

Task-number: QTBUG-44875
Change-Id: Idc1b1d063802ea350a6da6509bf967e898712f4d
Reviewed-by: Andy Nichols <andy.nichols@theqtcompany.com>

3 files changed, 79 insertions, 0 deletions

diff --git a/src/render/lights/qpointlight.cpp b/src/render/lights/qpointlight.cpp
index 539e99b00..58ff5b25e 100644
--- a/src/render/lights/qpointlight.cpp
+++ b/src/render/lights/qpointlight.cpp
@@ -63,6 +63,7 @@ namespace Qt3DRender {
     \internal
 */
 QPointLightPrivate::QPointLightPrivate()
+    : m_attenuation(0.0f, 0.0f, 0.002f)
 {
 }
 
@@ -97,6 +98,66 @@ QPointLight::QPointLight(QPointLightPrivate &dd, QNode *parent)
 {
 }
 
+QVector3D QPointLight::attenuation() const
+{
+    Q_D(const QPointLight);
+    return d->m_attenuation;
+}
+
+void QPointLight::setAttenuation(const QVector3D &value)
+{
+    Q_D(QPointLight);
+    if (d->m_attenuation != value) {
+        d->m_attenuation = value;
+        emit attenuationChanged();
+    }
+}
+
+float QPointLight::constantAttenuation() const
+{
+    Q_D(const QPointLight);
+    return d->m_attenuation.x();
+}
+
+void QPointLight::setConstantAttenuation(float value)
+{
+    Q_D(QPointLight);
+    if (d->m_attenuation.x() != value) {
+        d->m_attenuation.setX(value);
+        emit attenuationChanged();
+    }
+}
+
+float QPointLight::linearAttenuation() const
+{
+    Q_D(const QPointLight);
+    return d->m_attenuation.y();
+}
+
+void QPointLight::setLinearAttenuation(float value)
+{
+    Q_D(QPointLight);
+    if (d->m_attenuation.y() != value) {
+        d->m_attenuation.setY(value);
+        emit attenuationChanged();
+    }
+}
+
+float QPointLight::quadraticAttenuation() const
+{
+    Q_D(const QPointLight);
+    return d->m_attenuation.z();
+}
+
+void QPointLight::setQuadraticAttenuation(float value)
+{
+    Q_D(QPointLight);
+    if (d->m_attenuation.z() != value) {
+        d->m_attenuation.setZ(value);
+        emit attenuationChanged();
+    }
+}
+
 } // namespace Qt3DRender
 
 QT_END_NAMESPACE
diff --git a/src/render/lights/qpointlight.h b/src/render/lights/qpointlight.h
index eb8b447d7..75b4671d0 100644
--- a/src/render/lights/qpointlight.h
+++ b/src/render/lights/qpointlight.h
@@ -48,10 +48,26 @@ class QPointLightPrivate;
 class QT3DRENDERSHARED_EXPORT QPointLight : public QLight
 {
     Q_OBJECT
+    Q_PROPERTY(QVector3D attenuation READ attenuation WRITE setAttenuation NOTIFY attenuationChanged)
 
 public:
     explicit QPointLight(Qt3DCore::QNode *parent = 0);
 
+    QVector3D attenuation() const;
+    void setAttenuation(const QVector3D &value);
+
+    float constantAttenuation() const;
+    void setConstantAttenuation(float value);
+
+    float linearAttenuation() const;
+    void setLinearAttenuation(float value);
+
+    float quadraticAttenuation() const;
+    void setQuadraticAttenuation(float value);
+
+Q_SIGNALS:
+    void attenuationChanged();
+
 protected:
     Q_DECLARE_PRIVATE(QPointLight)
     QPointLight(QPointLightPrivate &dd, Qt3DCore::QNode *parent);
diff --git a/src/render/lights/qpointlight_p.h b/src/render/lights/qpointlight_p.h
index 2e2cd652e..2929ffd97 100644
--- a/src/render/lights/qpointlight_p.h
+++ b/src/render/lights/qpointlight_p.h
@@ -61,6 +61,8 @@ class QPointLightPrivate : public QLightPrivate
 public:
     QPointLightPrivate();
 
+    QVector3D m_attenuation;
+
     Q_DECLARE_PUBLIC(QPointLight)
 };