Surface gradient to theme and drawing implementation to renderer.

Change-Id: I78a3f3d0aa9bd24a05368545cf8e779dda65ef4c
Reviewed-by: Mika Salmela <mika.salmela@digia.com>

13 files changed, 127 insertions, 73 deletions

diff --git a/examples/surfacechart/chartmodifier.cpp b/examples/surfacechart/chartmodifier.cpp
index a78b2d2e..010c0b6f 100644
--- a/examples/surfacechart/chartmodifier.cpp
+++ b/examples/surfacechart/chartmodifier.cpp
@@ -85,7 +85,7 @@ void ChartModifier::toggleSqrtSin(bool enable)
         for (qreal i = -8.0 + stepZ / 2.0 ; i < 8.0 ; i += stepZ) {
             for (qreal j = -8.0 + stepX / 2.0; j < 8.0; j += stepX) {
                 qreal R = qSqrt(i*i + j*j) + 0.01;
-                qreal y = sin(R)/R + 1.0;
+                qreal y = (sin(R)/R + 0.24) * 1.61;
                 series << y;
                 if (y > biggest) biggest = y;
                 if (y < smallest) smallest = y;
@@ -101,6 +101,24 @@ void ChartModifier::toggleSqrtSin(bool enable)
     }
 }
 
+void ChartModifier::togglePlane(bool enable)
+{
+    qDebug() << "ChartModifier::togglePlane " << enable;
+    if (enable) {
+        QList<qreal> series;
+
+        qreal y = 2.0 / qreal(m_xCount - 1);
+        for (int i = 0; i < m_zCount; i++) {
+            for (int j = 0; j < m_xCount; j++) {
+                series << j * y;
+            }
+        }
+
+        m_chart->setTickCount(4, 0.5f);
+        m_chart->appendSeries(series, m_xCount, m_zCount);
+    }
+}
+
 void ChartModifier::toggleGridSliderLock(bool enable)
 {
     m_gridSlidersLocked = enable;
diff --git a/examples/surfacechart/chartmodifier.h b/examples/surfacechart/chartmodifier.h
index 8b84efbb..3daf96ed 100644
--- a/examples/surfacechart/chartmodifier.h
+++ b/examples/surfacechart/chartmodifier.h
@@ -56,6 +56,7 @@ public:
     void toggleSmooth(bool enabled);
     void toggleSurfaceGrid(bool enable);
     void toggleSqrtSin(bool enable);
+    void togglePlane(bool enable);
     void toggleGridSliderLock(bool enable);
     void setGridSliderX(QSlider *slider) { m_gridSliderX = slider; }
     void setGridSliderZ(QSlider *slider) { m_gridSliderZ = slider; }
diff --git a/examples/surfacechart/main.cpp b/examples/surfacechart/main.cpp
index 474f273b..c9d95c67 100644
--- a/examples/surfacechart/main.cpp
+++ b/examples/surfacechart/main.cpp
@@ -51,6 +51,8 @@
 #include <QSlider>
 #include <QLabel>
 #include <QScreen>
+#include <QPainter>
+#include <QDebug>
 
 using namespace QtDataVis3D;
 
@@ -89,6 +91,10 @@ int main(int argc, char *argv[])
     sqrtSinCB->setText(QStringLiteral("Sqrt & Sin"));
     sqrtSinCB->setChecked(false);
 
+    QCheckBox *planeCB = new QCheckBox(widget);
+    planeCB->setText(QStringLiteral("Plane"));
+    planeCB->setChecked(false);
+
     QCheckBox *gridSlidersLockCB = new QCheckBox(widget);
     gridSlidersLockCB->setText(QStringLiteral("Lock"));
     gridSlidersLockCB->setChecked(false);
@@ -106,16 +112,32 @@ int main(int argc, char *argv[])
     gridSliderZ->setMaximum(200);
     gridSliderZ->setEnabled(true);
 
+    QLinearGradient gr(0, 0, 100, 1);
+    gr.setColorAt(0.0, Qt::green);
+    gr.setColorAt(0.5, Qt::yellow);
+    gr.setColorAt(1.0, Qt::red);
+    QPixmap pm(100, 24);
+    QPainter pmp(&pm);
+    pmp.setBrush(QBrush(gr));
+    pmp.setPen(Qt::NoPen);
+    pmp.drawRect(0, 0, 100, 24);
+    //pm.save("C:\\Users\\misalmel\\Work\\test.png", "png");
+    QPushButton *color = new QPushButton();
+    color->setIcon(QIcon(pm));
+    color->setIconSize(QSize(100, 24));
+    color->setFlat(true);
 
     // Add controls to the layout
     vLayout->addWidget(smoothCB);
     vLayout->addWidget(surfaceGridCB);
-    vLayout->addWidget(new QLabel(QStringLiteral("Select surface")));
+    vLayout->addWidget(new QLabel(QStringLiteral("Select surface sample")));
     vLayout->addWidget(sqrtSinCB);
+    vLayout->addWidget(planeCB);
     vLayout->addWidget(new QLabel(QStringLiteral("Adjust sample count")));
     vLayout->addWidget(gridSlidersLockCB);
     vLayout->addWidget(gridSliderX);
     vLayout->addWidget(gridSliderZ);
+    vLayout->addWidget(color);
 
     widget->show();
 
@@ -128,6 +150,8 @@ int main(int argc, char *argv[])
                      modifier, &ChartModifier::toggleSurfaceGrid);
     QObject::connect(sqrtSinCB, &QCheckBox::stateChanged,
                      modifier, &ChartModifier::toggleSqrtSin);
+    QObject::connect(planeCB, &QCheckBox::stateChanged,
+                     modifier, &ChartModifier::togglePlane);
     QObject::connect(gridSlidersLockCB, &QCheckBox::stateChanged,
                      modifier, &ChartModifier::toggleGridSliderLock);
     QObject::connect(gridSliderX, &QSlider::valueChanged,
diff --git a/src/datavis3d/engine/q3dsurface.cpp b/src/datavis3d/engine/q3dsurface.cpp
index 951c3e58..c4465165 100644
--- a/src/datavis3d/engine/q3dsurface.cpp
+++ b/src/datavis3d/engine/q3dsurface.cpp
@@ -147,6 +147,11 @@ void Q3DSurface::setTickCount(int tickCount, qreal step, qreal minimum)
     d_ptr->m_shared->setTickCount(GLint(tickCount), GLfloat(step), GLfloat(minimum));
 }
 
+void Q3DSurface::setGradientColorAt(qreal pos, const QColor &color)
+{
+    d_ptr->m_shared->setGradientColorAt(pos, color);
+}
+
 // TODO /////////////////////////////////////////
 void Q3DSurface::appendSeries(QList<qreal> series, int width, int depth )
 {
diff --git a/src/datavis3d/engine/q3dsurface.h b/src/datavis3d/engine/q3dsurface.h
index 03be2f17..3c169a84 100644
--- a/src/datavis3d/engine/q3dsurface.h
+++ b/src/datavis3d/engine/q3dsurface.h
@@ -67,6 +67,8 @@ public:
     void setSurfaceGrid(bool enable);
     bool surfaceGrid();
 
+    void setGradientColorAt(qreal pos, const QColor &color);
+
     // Set tick count and step. Note; tickCount * step should be the maximum possible value of data
     // set. Minimum is the absolute minimum possible value a bar can have. This is especially
     // important to set if values can be negative.
diff --git a/src/datavis3d/engine/shaders/surface.frag b/src/datavis3d/engine/shaders/surface.frag
index af75cbb9..c67055fe 100644
--- a/src/datavis3d/engine/shaders/surface.frag
+++ b/src/datavis3d/engine/shaders/surface.frag
@@ -7,13 +7,15 @@ varying highp vec3 normal_cmr;
 varying highp vec3 eyeDirection_cmr;
 varying highp vec3 lightDirection_cmr;
 
+uniform sampler2D textureSampler;
 uniform highp vec3 lightPosition_wrld;
-uniform highp vec3 color_mdl;
+//uniform highp vec3 color_mdl;
 uniform highp float lightStrength;
 uniform highp float ambientStrength;
 
 void main() {
-    highp vec3 materialDiffuseColor = vec3(position_wrld.y, 1.0 - position_wrld.y, 0.0);
+    highp vec2 guv = vec2(0.5, (coords_mdl.y + 1.0) / 2.0);
+    highp vec3 materialDiffuseColor = texture2D(textureSampler, guv).xyz;
     highp vec3 materialAmbientColor = vec3(ambientStrength, ambientStrength, ambientStrength) * materialDiffuseColor;
     highp vec3 materialSpecularColor = vec3(1.0, 1.0, 1.0);
 
diff --git a/src/datavis3d/engine/shaders/surfaceFlat.frag b/src/datavis3d/engine/shaders/surfaceFlat.frag
index b07acbad..32efe274 100644
--- a/src/datavis3d/engine/shaders/surfaceFlat.frag
+++ b/src/datavis3d/engine/shaders/surfaceFlat.frag
@@ -7,13 +7,15 @@ flat in highp vec3 normal_cmr;
 varying highp vec3 eyeDirection_cmr;
 varying highp vec3 lightDirection_cmr;
 
+uniform sampler2D textureSampler;
 uniform highp vec3 lightPosition_wrld;
-uniform highp vec3 color_mdl;
+//uniform highp vec3 color_mdl;
 uniform highp float lightStrength;
 uniform highp float ambientStrength;
 
 void main() {
-    highp vec3 materialDiffuseColor = vec3(position_wrld.y, 1.0 - position_wrld.y, 0.0);
+    highp vec2 guv = vec2(0.5, (coords_mdl.y + 1.0) / 2.0);
+    highp vec3 materialDiffuseColor = texture2D(textureSampler, guv).xyz;
     highp vec3 materialAmbientColor = vec3(ambientStrength, ambientStrength, ambientStrength) * materialDiffuseColor;
     highp vec3 materialSpecularColor = vec3(1.0, 1.0, 1.0);
 
@@ -27,7 +29,7 @@ void main() {
     highp vec3 R = reflect(-l, n);
     highp float cosAlpha = clamp(dot(E, R), 0.0, 1.0);
 
-//    gl_FragColor.rgb = n;
+//    gl_FragColor.rgb = materialDiffuseColor;
     gl_FragColor.rgb =
         materialAmbientColor +
         materialDiffuseColor * lightStrength * pow(cosTheta, 2) / distance +
diff --git a/src/datavis3d/engine/surface3dcontroller.cpp b/src/datavis3d/engine/surface3dcontroller.cpp
index ca24da09..9996e1b8 100644
--- a/src/datavis3d/engine/surface3dcontroller.cpp
+++ b/src/datavis3d/engine/surface3dcontroller.cpp
@@ -191,6 +191,12 @@ void Surface3dController::setTickCount(GLint tickCount, GLfloat step, GLfloat mi
     emit tickCountChanged(m_tickCount, m_tickStep, m_tickMinimum);
 }
 
+void Surface3dController::setGradientColorAt(qreal pos, const QColor &color)
+{
+    Theme t = theme();
+    t.m_surfaceGradient.setColorAt(pos, color);
+    emit themeChanged(t);
+}
 
 // TODO: Temp
 void Surface3dController::setData(QList<qreal> series, int width, int depth)
diff --git a/src/datavis3d/engine/surface3dcontroller_p.h b/src/datavis3d/engine/surface3dcontroller_p.h
index 3207f6f3..021e32d3 100644
--- a/src/datavis3d/engine/surface3dcontroller_p.h
+++ b/src/datavis3d/engine/surface3dcontroller_p.h
@@ -55,6 +55,8 @@
 #include "abstract3dcontroller_p.h"
 #include "datavis3dglobal_p.h"
 
+#include <QLinearGradient>
+
 QT_DATAVIS3D_BEGIN_NAMESPACE
 
 class Surface3dRenderer;
@@ -101,6 +103,8 @@ public:
     void setSurfaceGrid(bool enable);
     bool surfaceGrid();
 
+    void setGradientColorAt(qreal pos, const QColor &color);
+
     // Set tick count and step. Note; tickCount * step should be the maximum possible value of data
     // set. Minimum is the absolute minimum possible value a bar can have. This is especially
     // important to set if values can be negative.
diff --git a/src/datavis3d/engine/surface3drenderer.cpp b/src/datavis3d/engine/surface3drenderer.cpp
index 1cd9231e..01bb8c7e 100644
--- a/src/datavis3d/engine/surface3drenderer.cpp
+++ b/src/datavis3d/engine/surface3drenderer.cpp
@@ -54,6 +54,9 @@
 #include <QMouseEvent>
 #include <qmath.h>
 
+#include <QLinearGradient>
+#include <QPainter>
+
 #include <QDebug>
 
 QT_DATAVIS3D_BEGIN_NAMESPACE
@@ -63,7 +66,6 @@ Surface3dRenderer::Surface3dRenderer(Surface3dController *controller)
       m_controller(controller),
       m_mousePressed(MouseNone),
       m_mousePos(QPoint(0, 0)),
-      m_theme(new Theme()),
       m_isGridEnabled(true),
       m_isBackgroundEnabled(true),
       m_shadowQuality(ShadowLow),
@@ -92,8 +94,9 @@ Surface3dRenderer::Surface3dRenderer(Surface3dController *controller)
       m_surfaceObj(0),
       m_depthTexture(0),
       m_depthFrameBuffer(0),
+      m_gradientTexture(0),
       m_shadowQualityToShader(33.3f),
-      m_drawer(new Drawer(*m_theme, m_font, m_labelTransparency))
+      m_drawer(new Drawer(m_cachedTheme, m_font, m_labelTransparency))
 {
     // Listen to changes in the controller
     QObject::connect(m_controller, &Surface3dController::smoothStatusChanged, this,
@@ -102,9 +105,12 @@ Surface3dRenderer::Surface3dRenderer(Surface3dController *controller)
                      &Surface3dRenderer::updateSurfaceGridStatus);
     QObject::connect(m_controller, &Surface3dController::tickCountChanged, this,
                      &Surface3dRenderer::updateTickCount);
+    QObject::connect(m_controller, &Surface3dController::themeChanged, this,
+                     &Surface3dRenderer::updateTheme);
 
     m_cachedSmoothSurface =  m_controller->smoothSurface();
     updateSurfaceGridStatus(m_controller->surfaceGrid());
+    updateTheme(m_controller->theme());
 
     initializeOpenGL();
 }
@@ -117,8 +123,8 @@ Surface3dRenderer::~Surface3dRenderer()
     if (m_backgroundShader)
         delete m_backgroundShader;
 
-    if (m_depthTexture)
-        m_textureHelper->deleteTexture(&m_depthTexture);
+    m_textureHelper->deleteTexture(&m_depthTexture);
+    m_textureHelper->deleteTexture(&m_gradientTexture);
 
     delete m_backgroundObj;
     delete m_surfaceObj;
@@ -204,7 +210,7 @@ void Surface3dRenderer::render(CameraHelper *camera, const GLuint defaultFboHand
         glCullFace(GL_BACK);
     }
 
-    QVector3D clearColor = Utils::vectorFromColor(m_theme->m_windowColor);
+    QVector3D clearColor = Utils::vectorFromColor(m_cachedTheme.m_windowColor);
     glClearColor(clearColor.x(), clearColor.y(), clearColor.z(), 1.0f);
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
@@ -294,25 +300,22 @@ void Surface3dRenderer::drawScene(CameraHelper *camera, const GLuint defaultFboH
         // TODO Check the usage?
         depthMVPMatrix = depthProjectionMatrix * depthViewMatrix * modelMatrix;
 
-        QVector3D baseColor = Utils::vectorFromColor(QColor(Qt::red)/*m_theme->m_baseColor*/);
-
         // Set shader bindings
         m_surfaceShader->setUniformValue(m_surfaceShader->lightP(), lightPos);
         m_surfaceShader->setUniformValue(m_surfaceShader->view(), viewMatrix);
         m_surfaceShader->setUniformValue(m_surfaceShader->model(), modelMatrix);
         m_surfaceShader->setUniformValue(m_surfaceShader->nModel(), itModelMatrix.inverted().transposed());
         m_surfaceShader->setUniformValue(m_surfaceShader->MVP(), MVPMatrix);
-        m_surfaceShader->setUniformValue(m_surfaceShader->color(), baseColor);
-        m_surfaceShader->setUniformValue(m_surfaceShader->ambientS(), m_theme->m_ambientStrength);
+        m_surfaceShader->setUniformValue(m_surfaceShader->ambientS(), m_cachedTheme.m_ambientStrength);
 
         //IF QT_OPENGL_ES_2 TODO
         // Shadow quality etc.
         //m_backgroundShader->setUniformValue(m_backgroundShader->shadowQ(), m_shadowQualityToShader);
         //m_backgroundShader->setUniformValue(m_backgroundShader->depth(), depthMVPMatrix);
         m_surfaceShader->setUniformValue(m_surfaceShader->lightS(),
-                                            m_theme->m_lightStrength * 2.0f);
+                                            m_cachedTheme.m_lightStrength * 2.0f);
 
-        m_drawer->drawObject(m_surfaceShader, m_surfaceObj, 0, m_depthTexture);
+        m_drawer->drawObject(m_surfaceShader, m_surfaceObj, m_gradientTexture, m_depthTexture);
         m_surfaceShader->release();
 
         if (m_cachedSurfaceGridOn) {
@@ -370,7 +373,7 @@ void Surface3dRenderer::drawScene(CameraHelper *camera, const GLuint defaultFboH
 #endif
         depthMVPMatrix = depthProjectionMatrix * depthViewMatrix * modelMatrix;
 
-        QVector3D backgroundColor = Utils::vectorFromColor(m_theme->m_backgroundColor);
+        QVector3D backgroundColor = Utils::vectorFromColor(m_cachedTheme.m_backgroundColor);
 
         // Set shader bindings
         m_backgroundShader->setUniformValue(m_backgroundShader->lightP(), lightPos);
@@ -381,7 +384,7 @@ void Surface3dRenderer::drawScene(CameraHelper *camera, const GLuint defaultFboH
         m_backgroundShader->setUniformValue(m_backgroundShader->MVP(), MVPMatrix);
         m_backgroundShader->setUniformValue(m_backgroundShader->color(), backgroundColor);
         m_backgroundShader->setUniformValue(m_backgroundShader->ambientS(),
-                                            m_theme->m_ambientStrength * 2.0f);
+                                            m_cachedTheme.m_ambientStrength * 2.0f);
 
 #if !defined(QT_OPENGL_ES_2)
         if (m_shadowQuality > ShadowNone) {
@@ -390,7 +393,7 @@ void Surface3dRenderer::drawScene(CameraHelper *camera, const GLuint defaultFboH
                                                 m_shadowQualityToShader);
             m_backgroundShader->setUniformValue(m_backgroundShader->depth(), depthMVPMatrix);
             m_backgroundShader->setUniformValue(m_backgroundShader->lightS(),
-                                                m_theme->m_lightStrength / 10.0f);
+                                                m_cachedTheme.m_lightStrength / 10.0f);
 
             // Draw the object
             m_drawer->drawObject(m_backgroundShader, m_backgroundObj, 0, m_depthTexture);
@@ -399,7 +402,7 @@ void Surface3dRenderer::drawScene(CameraHelper *camera, const GLuint defaultFboH
         {
             // Set shadowless shader bindings
             m_backgroundShader->setUniformValue(m_backgroundShader->lightS(),
-                                                m_theme->m_lightStrength);
+                                                m_cachedTheme.m_lightStrength);
 
             // Draw the object
             m_drawer->drawObject(m_backgroundShader, m_backgroundObj);
@@ -443,16 +446,33 @@ void Surface3dRenderer::setXZStuff(GLint tickXCount, GLint tickZCount)
     calculateSceneScalingFactors();
 }
 
+void Surface3dRenderer::updateTheme(Theme theme)
+{
+    m_cachedTheme.setFromTheme(theme);
+
+    // Update things depending from the theme
+    updateSurfaceGradient();
+}
+
+void Surface3dRenderer::updateSurfaceGradient()
+{
+    QImage image(QSize(4, 100), QImage::Format_RGB32);
+    QPainter pmp(&image);
+    pmp.setBrush(QBrush(m_cachedTheme.m_surfaceGradient));
+    pmp.setPen(Qt::NoPen);
+    pmp.drawRect(0, 0, 4, 100);
+    image.save("C:\\Users\\misalmel\\Work\\image.png", "png");
+
+    if (m_gradientTexture) {
+        m_textureHelper->deleteTexture(&m_gradientTexture);
+        m_gradientTexture = 0;
+    }
+
+    m_gradientTexture = m_textureHelper->create2DTexture(image, false, true);
+}
+
 void Surface3dRenderer::setSeries(QList<qreal> series)
 {
-//    QList<qreal> temp;
-//    temp.append(10);temp.append(150);temp.append(50);
-//    temp.append(10);temp.append(150);temp.append(50);
-//    temp.append(10);temp.append(150);temp.append(50);
-//    if (m_smoothSurface)
-//        m_surfaceObj->setUpSmoothData(temp, 3, 3, m_yRange);
-//    else
-//        m_surfaceObj->setUpData(temp, 3, 3, m_yRange);
     m_series = series;
 
     // TODO temp solution
@@ -600,40 +620,6 @@ int Surface3dRenderer::y()
     return m_boundingRect.y();
 }
 
-#if defined(Q_OS_ANDROID)
-void Surface3dRenderer::mouseDoubleClickEvent(QMouseEvent *event)
-{
-
-}
-
-void Surface3dRenderer::touchEvent(QTouchEvent *event)
-{
-
-}
-#endif
-void Surface3dRenderer::mousePressEvent(QMouseEvent *event, const QPoint &mousePos)
-{
-    Q_UNUSED(event)
-    Q_UNUSED(mousePos)
-}
-
-void Surface3dRenderer::mouseReleaseEvent(QMouseEvent *event, const QPoint &mousePos)
-{
-    Q_UNUSED(event)
-    Q_UNUSED(mousePos)
-}
-
-void Surface3dRenderer::mouseMoveEvent(QMouseEvent *event, const QPoint &mousePos)
-{
-    Q_UNUSED(event)
-    Q_UNUSED(mousePos)
-}
-
-void Surface3dRenderer::wheelEvent(QWheelEvent *event)
-{
-    Q_UNUSED(event)
-}
-
 void Surface3dRenderer::handleResize()
 {
     if (!m_isInitialized)
diff --git a/src/datavis3d/engine/surface3drenderer_p.h b/src/datavis3d/engine/surface3drenderer_p.h
index 1d6ffafe..7c3ca040 100644
--- a/src/datavis3d/engine/surface3drenderer_p.h
+++ b/src/datavis3d/engine/surface3drenderer_p.h
@@ -56,6 +56,7 @@
 #include <QtCore/QObject>
 #include <QtGui/QOpenGLFunctions>
 #include <QtGui/QFont>
+#include <QLinearGradient>
 #include <QWindow>
 
 #include "datavis3dglobal_p.h"
@@ -96,7 +97,7 @@ public:
 
     // Visual parameters
     QRect m_boundingRect;
-    Theme *m_theme;
+    Theme m_cachedTheme;
     LabelTransparency m_labelTransparency;
     QFont m_font;
     bool m_isGridEnabled;
@@ -134,6 +135,7 @@ private:
     SurfaceObject *m_surfaceObj;
     GLuint m_depthTexture;
     GLuint m_depthFrameBuffer;
+    GLuint m_gradientTexture;
     GLfloat m_shadowQualityToShader;
     bool m_cachedSmoothSurface;
     bool m_cachedSurfaceGridOn;
@@ -151,8 +153,10 @@ public:
     Drawer *drawer() { return m_drawer; }
 
 public slots:
+    void updateTheme(Theme theme);
     void updateSmoothStatus(bool enable);
     void updateSurfaceGridStatus(bool enable);
+    void updateSurfaceGradient();
     void updateTickCount(GLint tickCount, GLfloat step, GLfloat minimum = 0.0f);
 
 public:
@@ -169,14 +173,6 @@ public:
     void setY(const int y);
     int y();
 
-#if defined(Q_OS_ANDROID)
-    void mouseDoubleClickEvent(QMouseEvent *event);
-    void touchEvent(QTouchEvent *event);
-#endif
-    void mousePressEvent(QMouseEvent *event, const QPoint &mousePos);
-    void mouseReleaseEvent(QMouseEvent *event, const QPoint &mousePos);
-    void mouseMoveEvent(QMouseEvent *event, const QPoint &mousePos);
-    void wheelEvent(QWheelEvent *event);
     void handleResize();
 
 #if !defined(QT_OPENGL_ES_2)
diff --git a/src/datavis3d/engine/theme.cpp b/src/datavis3d/engine/theme.cpp
index 796d32e6..5b6ff87a 100644
--- a/src/datavis3d/engine/theme.cpp
+++ b/src/datavis3d/engine/theme.cpp
@@ -60,11 +60,16 @@ Theme::Theme()
       m_highlightBarColor(QColor(Qt::red)),
       m_highlightRowColor(QColor(Qt::darkRed)),
       m_highlightColumnColor(QColor(Qt::darkMagenta)),
+      m_surfaceGradient(QLinearGradient(1, 100, 0, 0)),
       m_lightStrength(4.0f),
       m_ambientStrength(0.3f),
       m_highlightLightStrength(8.0f),
       m_uniformColor(true)
 {
+    // Default values for surface gradient
+    m_surfaceGradient.setColorAt(0.0, Qt::green);
+    m_surfaceGradient.setColorAt(0.5, Qt::yellow);
+    m_surfaceGradient.setColorAt(1.0, Qt::red);
 }
 
 Theme::~Theme()
@@ -315,6 +320,7 @@ void Theme::setFromTheme(Theme &theme)
     m_highlightBarColor = theme.m_highlightBarColor;
     m_highlightRowColor = theme.m_highlightRowColor;
     m_highlightColumnColor = theme.m_highlightColumnColor;
+    m_surfaceGradient = theme.m_surfaceGradient;
     m_lightStrength = theme.m_lightStrength;
     m_ambientStrength = theme.m_ambientStrength;
     m_highlightLightStrength = theme.m_highlightLightStrength;
diff --git a/src/datavis3d/engine/theme_p.h b/src/datavis3d/engine/theme_p.h
index 91275fd5..3de1c9ea 100644
--- a/src/datavis3d/engine/theme_p.h
+++ b/src/datavis3d/engine/theme_p.h
@@ -54,6 +54,7 @@
 
 #include "datavis3dglobal_p.h"
 #include "q3dbars.h"
+#include <QLinearGradient>
 
 class QColor;
 
@@ -89,6 +90,7 @@ private:
     QColor m_highlightBarColor;
     QColor m_highlightRowColor;
     QColor m_highlightColumnColor;
+    QLinearGradient m_surfaceGradient;
     float m_lightStrength;
     float m_ambientStrength;
     float m_highlightLightStrength;