diff --git a/playground/shapes/Gradient.cpp b/playground/shapes/Gradient.cpp
index 4c83c47c..c03b9b42 100644
--- a/playground/shapes/Gradient.cpp
+++ b/playground/shapes/Gradient.cpp
@@ -6,6 +6,31 @@
 #include "Gradient.h"
 #include <cassert>
 
+Gradient::Gradient( const Gradient& other ) noexcept
+    : m_stops( other.m_stops )
+    , m_values{ other.m_values[0], other.m_values[1], other.m_values[2],
+        other.m_values[3], other.m_values[4], other.m_values[5] }
+    , m_type( other.m_type )
+    , m_spread( other.m_spread )
+{
+}
+
+Gradient& Gradient::operator=( const Gradient& other ) noexcept
+{
+    m_type = other.m_type;
+    m_spread = other.m_spread;
+    m_stops = other.m_stops;
+
+    m_values[0] = other.m_values[0];
+    m_values[1] = other.m_values[1];
+    m_values[2] = other.m_values[2];
+    m_values[3] = other.m_values[3];
+    m_values[4] = other.m_values[4];
+    m_values[5] = other.m_values[5];
+
+    return *this;
+}
+
 bool Gradient::operator==( const Gradient& other ) const noexcept
 {
     if ( m_type != other.m_type )
@@ -210,12 +235,12 @@ void RadialGradient::setFocalPoint( qreal x, qreal y ) noexcept
     m_values[4] = y;
 }
 
-constexpr void RadialGradient::setCenterRadius( qreal radius ) noexcept
+void RadialGradient::setCenterRadius( qreal radius ) noexcept
 {
     m_values[2] = radius;
 }
 
-constexpr void RadialGradient::setFocalRadius( qreal radius ) noexcept
+void RadialGradient::setFocalRadius( qreal radius ) noexcept
 {
     m_values[5] = radius;
 }
diff --git a/playground/shapes/Gradient.h b/playground/shapes/Gradient.h
index 56e464ae..bdb1fc33 100644
--- a/playground/shapes/Gradient.h
+++ b/playground/shapes/Gradient.h
@@ -22,8 +22,10 @@ class ConicGradient;
 class Gradient
 {
   public:
-    constexpr Gradient() noexcept = default;
-    Gradient( const Gradient& ) noexcept = default;
+    Gradient() noexcept = default;
+    Gradient( const Gradient& ) noexcept;
+
+    Gradient& operator=( const Gradient& ) noexcept;
 
     bool operator==( const Gradient& ) const noexcept;
     bool operator!=( const Gradient& ) const noexcept;
@@ -60,8 +62,8 @@ class Gradient
     friend class RadialGradient;
     friend class ConicGradient;
 
-    constexpr Gradient( QGradient::Type ) noexcept;
-    constexpr Gradient( QGradient::Type,
+    Gradient( QGradient::Type ) noexcept;
+    Gradient( QGradient::Type,
         qreal, qreal, qreal, qreal, qreal, qreal ) noexcept;
 
     QVector< QskGradientStop > m_stops;
@@ -80,9 +82,9 @@ class Gradient
 class LinearGradient : public Gradient
 {
   public:
-    constexpr LinearGradient() noexcept;
-    constexpr LinearGradient( const QPointF&, const QPointF& ) noexcept;
-    constexpr LinearGradient( qreal x1, qreal y1, qreal x2, qreal y2 ) noexcept;
+    LinearGradient() noexcept;
+    LinearGradient( const QPointF&, const QPointF& ) noexcept;
+    LinearGradient( qreal x1, qreal y1, qreal x2, qreal y2 ) noexcept;
 
     void setStart(const QPointF& start) noexcept;
     void setStart( qreal x, qreal y ) noexcept;
@@ -104,15 +106,15 @@ QDebug operator<<( QDebug, const Gradient& );
 class RadialGradient : public Gradient
 {
   public:
-    constexpr RadialGradient() noexcept;
+    RadialGradient() noexcept;
 
-    constexpr RadialGradient( const QPointF& center, qreal radius ) noexcept;
-    constexpr RadialGradient( qreal cx, qreal cy, qreal radius ) noexcept;
+    RadialGradient( const QPointF& center, qreal radius ) noexcept;
+    RadialGradient( qreal cx, qreal cy, qreal radius ) noexcept;
 
-    constexpr RadialGradient( const QPointF& center, qreal centerRadius,
+    RadialGradient( const QPointF& center, qreal centerRadius,
         const QPointF& focalPoint, qreal focalRadius = 0.0 ) noexcept;
 
-    constexpr RadialGradient(qreal cx, qreal cy, qreal centerRadius,
+    RadialGradient(qreal cx, qreal cy, qreal centerRadius,
         qreal fx, qreal fy, qreal focalRadius = 0.0 ) noexcept;
 
     constexpr QPointF center() const noexcept;
@@ -124,18 +126,18 @@ class RadialGradient : public Gradient
     void setFocalPoint( qreal x, qreal y ) noexcept;
 
     constexpr qreal centerRadius() const noexcept;
-    constexpr void setCenterRadius( qreal radius ) noexcept;
+    void setCenterRadius( qreal radius ) noexcept;
 
     constexpr qreal focalRadius() const noexcept;
-    constexpr void setFocalRadius( qreal radius ) noexcept;
+    void setFocalRadius( qreal radius ) noexcept;
 };
 
 class ConicGradient : public Gradient
 {
   public:
-    constexpr ConicGradient() noexcept;
-    constexpr ConicGradient( const QPointF&, qreal degrees ) noexcept;
-    constexpr ConicGradient( qreal cx, qreal cy, qreal degrees ) noexcept;
+    ConicGradient() noexcept;
+    ConicGradient( const QPointF&, qreal degrees ) noexcept;
+    ConicGradient( qreal cx, qreal cy, qreal degrees ) noexcept;
 
     constexpr QPointF center() const noexcept;
     void setCenter(const QPointF& center) noexcept;
@@ -145,12 +147,12 @@ class ConicGradient : public Gradient
     void setDegrees(qreal ) noexcept;
 };
 
-constexpr Gradient::Gradient( QGradient::Type type ) noexcept
+inline Gradient::Gradient( QGradient::Type type ) noexcept
     : m_type( type )
 {
 }
 
-constexpr Gradient::Gradient( QGradient::Type type,
+inline Gradient::Gradient( QGradient::Type type,
         qreal v1, qreal v2, qreal v3,
         qreal v4 = 0.0, qreal v5 = 0.0, qreal v6 = 0.0  ) noexcept
     : m_values{ v1, v2, v3, v4, v5, v6 }
@@ -183,18 +185,18 @@ inline constexpr QGradient::Spread Gradient::spread() const noexcept
     return m_spread;
 }
 
-inline constexpr LinearGradient::LinearGradient() noexcept
+inline LinearGradient::LinearGradient() noexcept
     : Gradient( QGradient::LinearGradient, 0.0, 0.0, 1.0, 1.0 )
 {
 }
 
-inline constexpr LinearGradient::LinearGradient(
+inline LinearGradient::LinearGradient(
         const QPointF& start, const QPointF& stop ) noexcept
     : LinearGradient( start.x(), start.y(), stop.x(), stop.y() )
 {
 }
 
-inline constexpr LinearGradient::LinearGradient(
+inline LinearGradient::LinearGradient(
         qreal x1, qreal y1, qreal x2, qreal y2 ) noexcept
     : Gradient( QGradient::LinearGradient, x1, y1, x2, y2 )
 {
@@ -210,12 +212,12 @@ inline constexpr QPointF LinearGradient::stop() const noexcept
     return QPointF( m_values[2], m_values[3] );
 }
 
-inline constexpr RadialGradient::RadialGradient() noexcept
+inline RadialGradient::RadialGradient() noexcept
     : Gradient( QGradient::RadialGradient, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0 )
 {
 }
 
-inline constexpr RadialGradient::RadialGradient(
+inline RadialGradient::RadialGradient(
         const QPointF& center, qreal radius,
         const QPointF& focalPoint, qreal focalRadius ) noexcept
     : RadialGradient( center.x(), center.y(), radius,
@@ -223,19 +225,19 @@ inline constexpr RadialGradient::RadialGradient(
 {
 }
 
-inline constexpr RadialGradient::RadialGradient(
+inline RadialGradient::RadialGradient(
         const QPointF& center, qreal radius ) noexcept
     : RadialGradient( center.x(), center.y(), radius )
 {
 }
 
-inline constexpr RadialGradient::RadialGradient(
+inline RadialGradient::RadialGradient(
         qreal cx, qreal cy, qreal radius ) noexcept
     : RadialGradient( cx, cy, radius, cx, cy, 0.0 )
 {
 }
 
-inline constexpr RadialGradient::RadialGradient(
+inline RadialGradient::RadialGradient(
         qreal cx, qreal cy, qreal radius,
         qreal fx, qreal fy, qreal focalRadius  ) noexcept
     : Gradient( QGradient::RadialGradient, cx, cy, radius, fx, fy, focalRadius )
@@ -262,18 +264,18 @@ inline constexpr qreal RadialGradient::focalRadius() const noexcept
     return m_values[5];
 }
 
-inline constexpr ConicGradient::ConicGradient() noexcept
+inline ConicGradient::ConicGradient() noexcept
     : Gradient( QGradient::ConicalGradient, 0.0, 0.0, 0.0 )
 {
 }
 
-inline constexpr ConicGradient::ConicGradient(
+inline ConicGradient::ConicGradient(
         const QPointF& center, qreal degrees ) noexcept
     : ConicGradient( center.x(), center.y(), degrees )
 {
 }
 
-inline constexpr ConicGradient::ConicGradient(
+inline ConicGradient::ConicGradient(
         qreal cx, qreal cy, qreal degrees ) noexcept
     : Gradient( QGradient::ConicalGradient, cx, cy, degrees )
 {
diff --git a/src/nodes/QskGradientMaterial.cpp b/src/nodes/QskGradientMaterial.cpp
index 8fc1c297..f9a4da8c 100644
--- a/src/nodes/QskGradientMaterial.cpp
+++ b/src/nodes/QskGradientMaterial.cpp
@@ -601,8 +601,8 @@ namespace
 
             auto p = program();
 
-            m_centerPointId = p->uniformLocation( "translationPoint" );
-            m_focalPointId = p->uniformLocation( "focalToCenter" );
+            m_focalPointId = p->uniformLocation( "translationPoint" );
+            m_focalToCenterId = p->uniformLocation( "focalToCenter" );
             m_centerRadiusId = p->uniformLocation( "centerRadius" );
             m_focalRadiusId = p->uniformLocation( "focalRadius" );
         }
@@ -613,14 +613,14 @@ namespace
 
             auto p = program();
 
-            p->setUniformValue( m_centerPointId, material->m_center );
+            p->setUniformValue( m_focalToCenterId, material->m_focalToCenter );
             p->setUniformValue( m_centerRadiusId, material->m_centerRadius);
             p->setUniformValue( m_focalRadiusId, material->m_focalRadius);
             p->setUniformValue( m_focalPointId, material->m_focalPoint);
         }
 
       private:
-        int m_centerPointId = -1;
+        int m_focalToCenterId = -1;
         int m_focalPointId = -1;
         int m_centerRadiusId = -1;
         int m_focalRadiusId = -1;