Gradient support Part 1

TODO:
 - Finish scatter
 - QML (maybe left until data set is sorted, though)

Change-Id: I87a8117cb29f147080e0662c55b1098cb2e71689
Reviewed-by: Tomi Korpipää <tomi.korpipaa@digia.com>

4 files changed, 35 insertions, 1 deletions

diff --git a/src/datavisualization/utils/shaderhelper.cpp b/src/datavisualization/utils/shaderhelper.cpp
index e27103af..7eb48945 100644
--- a/src/datavisualization/utils/shaderhelper.cpp
+++ b/src/datavisualization/utils/shaderhelper.cpp
@@ -90,7 +90,8 @@ void ShaderHelper::initialize()
     m_colorUniform = m_program->uniformLocation("color_mdl");
     m_textureUniform = m_program->uniformLocation("textureSampler");
     m_shadowUniform = m_program->uniformLocation("shadowMap");
-
+    m_gradientMinUniform = m_program->uniformLocation("gradMin");
+    m_gradientHeightUniform = m_program->uniformLocation("gradHeight");
     m_initialized = true;
 }
 
@@ -230,6 +231,20 @@ GLuint ShaderHelper::shadow()
     return m_shadowUniform;
 }
 
+GLuint ShaderHelper::gradientMin()
+{
+    if (!m_initialized)
+        qFatal("Shader not initialized");
+    return m_gradientMinUniform;
+}
+
+GLuint ShaderHelper::gradientHeight()
+{
+    if (!m_initialized)
+        qFatal("Shader not initialized");
+    return m_gradientHeightUniform;
+}
+
 GLuint ShaderHelper::posAtt()
 {
     if (!m_initialized)
diff --git a/src/datavisualization/utils/shaderhelper_p.h b/src/datavisualization/utils/shaderhelper_p.h
index 73e5b9ee..191b7bf6 100644
--- a/src/datavisualization/utils/shaderhelper_p.h
+++ b/src/datavisualization/utils/shaderhelper_p.h
@@ -71,6 +71,8 @@ class ShaderHelper
     GLuint color();
     GLuint texture();
     GLuint shadow();
+    GLuint gradientMin();
+    GLuint gradientHeight();
 
     GLuint posAtt();
     GLuint uvAtt();
@@ -102,6 +104,8 @@ class ShaderHelper
     GLuint m_shadowQualityUniform;
     GLuint m_textureUniform;
     GLuint m_shadowUniform;
+    GLuint m_gradientMinUniform;
+    GLuint m_gradientHeightUniform;
 
     GLboolean m_initialized;
 };
diff --git a/src/datavisualization/utils/texturehelper.cpp b/src/datavisualization/utils/texturehelper.cpp
index 9e2b9811..8e556b44 100644
--- a/src/datavisualization/utils/texturehelper.cpp
+++ b/src/datavisualization/utils/texturehelper.cpp
@@ -20,6 +20,7 @@
 #include "utils_p.h"
 
 #include <QImage>
+#include <QPainter>
 
 #include <QDebug>
 
@@ -152,6 +153,18 @@ GLuint TextureHelper::createSelectionTexture(const QSize &size, GLuint &frameBuf
     return textureid;
 }
 
+GLuint TextureHelper::createGradientTexture(const QLinearGradient &gradient)
+{
+    QImage image(QSize(int(gradientTextureWidth), int(gradientTextureHeight)),
+                 QImage::Format_RGB32);
+    QPainter pmp(&image);
+    pmp.setBrush(QBrush(gradient));
+    pmp.setPen(Qt::NoPen);
+    pmp.drawRect(0, 0, int(gradientTextureWidth), int(gradientTextureHeight));
+
+    return create2DTexture(image, false, true);
+}
+
 #if !defined(QT_OPENGL_ES_2)
 GLuint TextureHelper::createDepthTexture(const QSize &size, GLuint &frameBuffer, GLuint textureSize)
 {
diff --git a/src/datavisualization/utils/texturehelper_p.h b/src/datavisualization/utils/texturehelper_p.h
index 8371825e..b2657083 100644
--- a/src/datavisualization/utils/texturehelper_p.h
+++ b/src/datavisualization/utils/texturehelper_p.h
@@ -32,6 +32,7 @@
 #include "datavisualizationglobal_p.h"
 #include <QOpenGLFunctions>
 #include <QRgb>
+#include <QLinearGradient>
 
 QT_DATAVISUALIZATION_BEGIN_NAMESPACE
 
@@ -47,6 +48,7 @@ class TextureHelper : protected QOpenGLFunctions
     GLuint createCubeMapTexture(const QImage &image, bool useTrilinearFiltering = false);
     // Returns selection texture and inserts generated framebuffers to framebuffer parameters
     GLuint createSelectionTexture(const QSize &size, GLuint &frameBuffer, GLuint &depthBuffer);
+    GLuint createGradientTexture(const QLinearGradient &gradient);
 #if !defined(QT_OPENGL_ES_2)
     // Returns depth texture and inserts generated framebuffer to parameter
     GLuint createDepthTexture(const QSize &size, GLuint &frameBuffer, GLuint textureSize = 1);