path: root/kde-frameworks/kdeclarative/files/kdeclarative-5.57.0-fix-plotter-crash.patch

From 0aab7d23a2ce155c4beb5cf77fcac02c93b183b7 Mon Sep 17 00:00:00 2001
From: David Edmundson <kde@davidedmundson.co.uk>
Date: Thu, 18 Apr 2019 11:15:06 +0100
Subject: Plotter: Scope GL Program to lifespan of scenegraph node

Summary:
Currently the QOpenGLProgram was static. This works when you only have
one OpenGL context that is never invalidated.

Instead we shoul have a new program created for each context. There is
no benefit of being static when we can use the cached shader loading.

As we need a program per context, we would need to handle windowChanged
and sceneGraphInvalidated manually. Instead we can scope the program to
the QSGNode which will be deleted and recreated on the render thread
automatically by the scene graph backend.

We can also drop ManagedTextureNode and use
QSGSimpleTextureNode::setOwnsTexture which does the same thing.

BUG: 403453

Test Plan:
Created a CPU load viewer on my panel
Dragged it to my desktop
Previously that didn't render anything
Now it does

It should fix the crashes that we
see on window moves and handling sceneGraphInvalidated

Reviewers: #plasma

Subscribers: kde-frameworks-devel

Tags: #frameworks

Differential Revision: https://phabricator.kde.org/D20656
---
 src/qmlcontrols/kquickcontrolsaddons/plotter.cpp | 106 ++++++++++++++---------
 src/qmlcontrols/kquickcontrolsaddons/plotter.h   |  11 +--
 2 files changed, 68 insertions(+), 49 deletions(-)

diff --git a/src/qmlcontrols/kquickcontrolsaddons/plotter.cpp b/src/qmlcontrols/kquickcontrolsaddons/plotter.cpp
index 650151d..8495bbd 100644
--- a/src/qmlcontrols/kquickcontrolsaddons/plotter.cpp
+++ b/src/qmlcontrols/kquickcontrolsaddons/plotter.cpp
@@ -44,8 +44,6 @@
 
 #include <QDebug>
 
-#include <QuickAddons/ManagedTextureNode>
-
 #include <math.h>
 
 //completely arbitrary
@@ -262,16 +260,58 @@ void PlotTexture::recreate(const QSize &size)
     m_size = size;
 }
 
+class PlotSGNode: public QSGSimpleTextureNode
+{
+public:
+    PlotSGNode();
+    void bind() {
+        m_program->bind();
+    }
+    void setMatrix(const QMatrix4x4 &matrix) {
+        m_program->setUniformValue(u_matrix, matrix);
+    }
+    void setColor1(const QColor &color) {
+        m_program->setUniformValue(u_color1, color);
+    }
+    void setColor2(const QColor &color) {
+        m_program->setUniformValue(u_color2, color);
+    }
+    void setYMin(float min) {
+        m_program->setUniformValue(u_yMin, min);
+    }
+    void setYMax(float max) {
+        m_program->setUniformValue(u_yMax, max);
+    }
+    ~PlotSGNode() = default;
+private:
+    QScopedPointer<QOpenGLShaderProgram> m_program;
+    int u_matrix;
+    int u_color1;
+    int u_color2;
+    int u_yMin;
+    int u_yMax;
 
+};
+
+PlotSGNode::PlotSGNode():
+    m_program(new QOpenGLShaderProgram)
+{
+    setOwnsTexture(true);
+    m_program->addCacheableShaderFromSourceCode(QOpenGLShader::Vertex, vs_source);
+    m_program->addCacheableShaderFromSourceCode(QOpenGLShader::Fragment, fs_source);
+    m_program->bindAttributeLocation("vertex", 0);
+    m_program->link();
+
+    u_yMin = m_program->uniformLocation("yMin");
+    u_yMax = m_program->uniformLocation("yMax");
+    u_color1 = m_program->uniformLocation("color1");
+    u_color2 = m_program->uniformLocation("color2");
+    u_matrix = m_program->uniformLocation("matrix");
+}
 
-// ----------------------
 
-QOpenGLShaderProgram *Plotter::s_program = nullptr;
-int Plotter::u_matrix;
-int Plotter::u_color1;
-int Plotter::u_color2;
-int Plotter::u_yMin;
-int Plotter::u_yMax;
+
+// ----------------------
 
 Plotter::Plotter(QQuickItem *parent)
     : QQuickItem(parent),
@@ -652,18 +692,18 @@ void Plotter::render()
     glEnableVertexAttribArray(0);
 
     // Bind the shader program
-    s_program->bind();
-    s_program->setUniformValue(u_matrix, m_matrix);
+    m_node->bind();
+    m_node->setMatrix(m_matrix);
 
     // Draw the lines
     QColor color1 = m_gridColor;
     QColor color2 = m_gridColor;
     color1.setAlphaF(0.10);
     color2.setAlphaF(0.40);
-    s_program->setUniformValue(u_yMin, (float) 0.0);
-    s_program->setUniformValue(u_yMax, (float) height());
-    s_program->setUniformValue(u_color1, color1);
-    s_program->setUniformValue(u_color2, color2);
+    m_node->setYMin((float) 0.0);
+    m_node->setYMax((float) height());
+    m_node->setColor1(color1);
+    m_node->setColor2(color2);
 
     glDrawArrays(GL_LINES, 0, (m_horizontalLineCount+1) * 2 );
 
@@ -677,18 +717,18 @@ void Plotter::render()
         color2 = data->color();
         color2.setAlphaF(0.60);
         // Draw the graph
-        s_program->setUniformValue(u_yMin, min);
-        s_program->setUniformValue(u_yMax, max);
-        s_program->setUniformValue(u_color1, data->color());
-        s_program->setUniformValue(u_color2, color2);
+        m_node->setYMin(min);
+        m_node->setYMax(max);
+        m_node->setColor1(data->color());
+        m_node->setColor2(color2);
 
         //+2 is for the bottom line
         glDrawArrays(GL_TRIANGLE_STRIP, m_horizontalLineCount*2 + 2 + oldCount.first + oldCount.second, verticesCounts[data].first);
 
         oldCount.first += verticesCounts[data].first;
 
-        s_program->setUniformValue(u_color1, data->color());
-        s_program->setUniformValue(u_color2, data->color());
+        m_node->setColor1(data->color());
+        m_node->setColor2(data->color());
         glDrawArrays(GL_LINE_STRIP, m_horizontalLineCount*2 + 2 + oldCount.first + oldCount.second, verticesCounts[data].second);
 
         oldCount.second += verticesCounts[data].second;
@@ -697,8 +737,8 @@ void Plotter::render()
 
     glDisable(GL_BLEND);
 
-    s_program->setUniformValue(u_color1, m_gridColor);
-    s_program->setUniformValue(u_color2, m_gridColor);
+    m_node->setColor1(m_gridColor);
+    m_node->setColor2(m_gridColor);
     glDrawArrays(GL_LINES, vertices.count()-2, 2);
 
     if (m_haveMSAA && m_haveFramebufferBlit) {
@@ -723,7 +763,7 @@ QSGNode *Plotter::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *updateP
         return nullptr;
     }
 
-    ManagedTextureNode *n = static_cast<ManagedTextureNode *>(oldNode);
+    PlotSGNode *n = static_cast<PlotSGNode *>(oldNode);
 
     if (width() == 0 && height() == 0) {
         delete oldNode;
@@ -731,8 +771,8 @@ QSGNode *Plotter::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *updateP
     }
 
     if (!n) {
-        n = new ManagedTextureNode();
-        n->setTexture(QSharedPointer<QSGTexture>(new PlotTexture(window()->openglContext())));
+        n = new PlotSGNode();
+        n->setTexture(new PlotTexture(window()->openglContext()));
         n->setFiltering(QSGTexture::Linear);
 
         m_node = n;
@@ -786,20 +826,6 @@ QSGNode *Plotter::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *updateP
         m_initialized = true;
     }
 
-    if (!s_program) {
-        s_program = new QOpenGLShaderProgram;
-        s_program->addShaderFromSourceCode(QOpenGLShader::Vertex, vs_source);
-        s_program->addShaderFromSourceCode(QOpenGLShader::Fragment, fs_source);
-        s_program->bindAttributeLocation("vertex", 0);
-        s_program->link();
-
-        u_yMin = s_program->uniformLocation("yMin");
-        u_yMax = s_program->uniformLocation("yMax");
-        u_color1 = s_program->uniformLocation("color1");
-        u_color2 = s_program->uniformLocation("color2");
-        u_matrix = s_program->uniformLocation("matrix");
-    }
-
     //we need a size always equal or smaller, size.toSize() won't do
     const QSize targetTextureSize(qRound(boundingRect().size().width()), qRound(boundingRect().size().height()));
     if (n->texture()->textureSize() != targetTextureSize) {
diff --git a/src/qmlcontrols/kquickcontrolsaddons/plotter.h b/src/qmlcontrols/kquickcontrolsaddons/plotter.h
index 01c0ef2..11ae233 100644
--- a/src/qmlcontrols/kquickcontrolsaddons/plotter.h
+++ b/src/qmlcontrols/kquickcontrolsaddons/plotter.h
@@ -47,7 +47,7 @@
 #include <QQuickWindow>
 #include <QMutex>
 
-class ManagedTextureNode;
+class PlotSGNode;
 
 /**
  * a Plotter can draw a graph of values arriving from an arbitrary number of data sources
@@ -242,7 +242,7 @@ private:
     QList<PlotData *> m_plotData;
 
     GLuint m_fbo = 0;
-    ManagedTextureNode *m_node = nullptr;
+    PlotSGNode *m_node = nullptr;
     qreal m_min;
     qreal m_max;
     qreal m_rangeMax;
@@ -262,13 +262,6 @@ private:
     int m_samples;
     QPointer <QQuickWindow> m_window;
     QMutex m_mutex;
-
-    static QOpenGLShaderProgram *s_program;
-    static int u_matrix;
-    static int u_color1;
-    static int u_color2;
-    static int u_yMin;
-    static int u_yMax;
 };
 
 #endif
-- 
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