Merge branch 'master' of gitlab.com:SymbioticEDA/nextpnr

5 files changed, 501 insertions, 113 deletions

diff --git a/gui/designwidget.cc b/gui/designwidget.cc
index cc161c9e..0f87f06c 100644
--- a/gui/designwidget.cc
+++ b/gui/designwidget.cc
@@ -117,7 +117,7 @@ DesignWidget::DesignWidget(Context *_ctx, QWidget *parent)
     for (auto bel : ctx->getBels()) {

         auto name = ctx->getBelName(bel);

         bel_items.append(

-                new BelTreeItem(name, ElementType::BEL, QString(name.c_str())));

+                new BelTreeItem(name, ElementType::BEL, QString(name.c_str(ctx))));

     }

     bel_root->addChildren(bel_items);

 

@@ -129,7 +129,7 @@ DesignWidget::DesignWidget(Context *_ctx, QWidget *parent)
     for (auto wire : ctx->getWires()) {

         auto name = ctx->getWireName(wire);

         wire_items.append(new WireTreeItem(name, ElementType::WIRE,

-                                           QString(name.c_str())));

+                                           QString(name.c_str(ctx))));

     }

     wire_root->addChildren(wire_items);

 

@@ -141,7 +141,7 @@ DesignWidget::DesignWidget(Context *_ctx, QWidget *parent)
     for (auto pip : ctx->getPips()) {

         auto name = ctx->getPipName(pip);

         pip_items.append(

-                new PipTreeItem(name, ElementType::PIP, QString(name.c_str())));

+                new PipTreeItem(name, ElementType::PIP, QString(name.c_str(ctx))));

     }

     pip_root->addChildren(pip_items);

 

@@ -184,7 +184,7 @@ void DesignWidget::addProperty(QtVariantProperty *property, const QString &id)
 {

     propertyToId[property] = id;

     idToProperty[id] = property;

-    QtBrowserItem *item = propertyEditor->addProperty(property);

+    propertyEditor->addProperty(property);

 }

 

 void DesignWidget::clearProperties()

@@ -213,14 +213,14 @@ void DesignWidget::onItemClicked(QTreeWidgetItem *item, int pos)
 

         QtVariantProperty *topItem =

                 variantManager->addProperty(QVariant::String, QString("Name"));

-        topItem->setValue(QString(c.c_str()));

+        topItem->setValue(QString(c.c_str(ctx)));

         addProperty(topItem, QString("Name"));

     } else if (type == ElementType::WIRE) {

         IdString c = static_cast<WireTreeItem *>(item)->getData();

 

         QtVariantProperty *topItem =

                 variantManager->addProperty(QVariant::String, QString("Name"));

-        topItem->setValue(QString(c.c_str()));

+        topItem->setValue(QString(c.c_str(ctx)));

         addProperty(topItem, QString("Name"));

 

     } else if (type == ElementType::PIP) {

@@ -228,7 +228,7 @@ void DesignWidget::onItemClicked(QTreeWidgetItem *item, int pos)
 

         QtVariantProperty *topItem =

                 variantManager->addProperty(QVariant::String, QString("Name"));

-        topItem->setValue(QString(c.c_str()));

+        topItem->setValue(QString(c.c_str(ctx)));

         addProperty(topItem, QString("Name"));

     }

 }

diff --git a/gui/fpgaviewwidget.cc b/gui/fpgaviewwidget.cc
index 8119eae3..f9cfc900 100644
--- a/gui/fpgaviewwidget.cc
+++ b/gui/fpgaviewwidget.cc
@@ -1,15 +1,221 @@
-#include "fpgaviewwidget.h"
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Serge Bazanski <q3k@symbioticeda.com>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include <cstdio>
+#include <math.h>
+
 #include <QApplication>
 #include <QCoreApplication>
 #include <QMouseEvent>
 #include <QWidget>
-#include <math.h>
+
+#include "fpgaviewwidget.h"
+#include "log.h"
 #include "mainwindow.h"
 
 NEXTPNR_NAMESPACE_BEGIN
 
+void PolyLine::buildPoint(LineShaderData *building, const QVector2D *prev,
+                          const QVector2D *cur, const QVector2D *next) const
+{
+    // buildPoint emits two vertices per line point, along with normals to move
+    // them the right directio when rendering and miter to compensate for
+    // bends.
+
+    if (cur == nullptr) {
+        // BUG
+        return;
+    }
+
+    if (prev == nullptr && next == nullptr) {
+        // BUG
+        return;
+    }
+
+    // TODO(q3k): fast path for vertical/horizontal lines?
+
+    // TODO(q3k): consider moving some of the linear algebra to the GPU,
+    // they're better at this than poor old CPUs.
+
+    // Build two unit vectors pointing in the direction of the two segments
+    // defined by (prev, cur) and (cur, next)
+    QVector2D dprev, dnext;
+    if (prev == nullptr) {
+        dnext = *next - *cur;
+        dprev = dnext;
+    } else if (next == nullptr) {
+        dprev = *cur - *prev;
+        dnext = dprev;
+    } else {
+        dprev = *cur - *prev;
+        dnext = *next - *cur;
+    }
+    dprev.normalize();
+    dnext.normalize();
+
+    // Calculate tangent unit vector.
+    QVector2D tangent(dprev + dnext);
+    tangent.normalize();
+
+    // Calculate normal to tangent - this is the line on which the vectors need
+    // to be pushed to build a thickened line.
+    const QVector2D tangent_normal = QVector2D(-tangent.y(), tangent.x());
+
+    // Calculate normal to one of the lines.
+    const QVector2D dprev_normal = QVector2D(-dprev.y(), dprev.x());
+    // https://people.eecs.berkeley.edu/~sequin/CS184/IMGS/Sweep_PolyLine.jpg
+    // (the ^-1 is performed in the shader)
+    const float miter = QVector2D::dotProduct(tangent_normal, dprev_normal);
+
+    const float x = cur->x();
+    const float y = cur->y();
+    const float mx = tangent_normal.x();
+    const float my = tangent_normal.y();
+
+    // Push back 'left' vertex.
+    building->vertices.push_back(Vertex2DPOD(x, y));
+    building->normals.push_back(Vertex2DPOD(mx, my));
+    building->miters.push_back(miter);
+
+    // Push back 'right' vertex.
+    building->vertices.push_back(Vertex2DPOD(x, y));
+    building->normals.push_back(Vertex2DPOD(mx, my));
+    building->miters.push_back(-miter);
+}
+
+void PolyLine::build(LineShaderData &target) const
+{
+    if (points_.size() < 2) {
+        return;
+    }
+    const QVector2D *first = &points_.front();
+    const QVector2D *last = &points_.back();
+
+    // Index number of vertices, used to build the index buffer.
+    unsigned int startIndex = target.vertices.size();
+    unsigned int index = startIndex;
+
+    // For every point on the line, call buildPoint with (prev, point, next).
+    // If we're building a closed line, prev/next wrap around. Otherwise
+    // they are passed as nullptr and buildPoint interprets that accordinglu.
+    const QVector2D *prev = nullptr;
+
+    // Loop iterator used to ensure next is valid.
+    unsigned int i = 0;
+    for (const QVector2D &point : points_) {
+        const QVector2D *next = nullptr;
+        if (++i < points_.size()) {
+            next = (&point + 1);
+        }
+
+        // If the line is closed, wrap around. Otherwise, pass nullptr.
+        if (prev == nullptr && closed_) {
+            buildPoint(&target, last, &point, next);
+        } else if (next == nullptr && closed_) {
+            buildPoint(&target, prev, &point, first);
+        } else {
+            buildPoint(&target, prev, &point, next);
+        }
+
+        // If we have a prev point relative to cur, build a pair of triangles
+        // to render vertices into lines.
+        if (prev != nullptr) {
+            target.indices.push_back(index);
+            target.indices.push_back(index + 1);
+            target.indices.push_back(index + 2);
+
+            target.indices.push_back(index + 2);
+            target.indices.push_back(index + 1);
+            target.indices.push_back(index + 3);
+
+            index += 2;
+        }
+        prev = &point;
+    }
+
+    // If we're closed, build two more vertices that loop the line around.
+    if (closed_) {
+        target.indices.push_back(index);
+        target.indices.push_back(index + 1);
+        target.indices.push_back(startIndex);
+
+        target.indices.push_back(startIndex);
+        target.indices.push_back(index + 1);
+        target.indices.push_back(startIndex + 1);
+    }
+}
+
+bool LineShader::compile(void)
+{
+    program_ = new QOpenGLShaderProgram(parent_);
+    program_->addShaderFromSourceCode(QOpenGLShader::Vertex,
+                                      vertexShaderSource_);
+    program_->addShaderFromSourceCode(QOpenGLShader::Fragment,
+                                      fragmentShaderSource_);
+    if (!program_->link()) {
+        printf("could not link program: %s\n",
+               program_->log().toStdString().c_str());
+        return false;
+    }
+    attributes_.position = program_->attributeLocation("position");
+    attributes_.normal = program_->attributeLocation("normal");
+    attributes_.miter = program_->attributeLocation("miter");
+    uniforms_.thickness = program_->uniformLocation("thickness");
+    uniforms_.projection = program_->uniformLocation("projection");
+    uniforms_.color = program_->uniformLocation("color");
+
+    return true;
+}
+
+void LineShader::draw(const LineShaderData &line, const QMatrix4x4 &projection)
+{
+    auto gl = QOpenGLContext::currentContext()->functions();
+    program_->bind();
+
+    program_->setUniformValue(uniforms_.projection, projection);
+    program_->setUniformValue(uniforms_.thickness, line.thickness);
+    program_->setUniformValue(uniforms_.color, line.color.r, line.color.g,
+                              line.color.b, line.color.a);
+
+    gl->glVertexAttribPointer(attributes_.position, 2, GL_FLOAT, GL_FALSE, 0,
+                              &line.vertices[0]);
+    gl->glVertexAttribPointer(attributes_.normal, 2, GL_FLOAT, GL_FALSE, 0,
+                              &line.normals[0]);
+    gl->glVertexAttribPointer(attributes_.miter, 1, GL_FLOAT, GL_FALSE, 0,
+                              &line.miters[0]);
+
+    gl->glEnableVertexAttribArray(0);
+    gl->glEnableVertexAttribArray(1);
+    gl->glEnableVertexAttribArray(2);
+
+    gl->glDrawElements(GL_TRIANGLES, line.indices.size(), GL_UNSIGNED_INT,
+                       &line.indices[0]);
+
+    gl->glDisableVertexAttribArray(2);
+    gl->glDisableVertexAttribArray(1);
+    gl->glDisableVertexAttribArray(0);
+    program_->release();
+}
+
 FPGAViewWidget::FPGAViewWidget(QWidget *parent)
-        : QOpenGLWidget(parent), m_xMove(0), m_yMove(0), m_zDistance(1.0)
+        : QOpenGLWidget(parent), moveX_(0), moveY_(0), zoom_(10.0f),
+          lineShader_(this)
 {
     ctx = qobject_cast<BaseMainWindow *>(getMainWindow())->getContext();
 }
@@ -31,139 +237,127 @@ QSize FPGAViewWidget::sizeHint() const { return QSize(640, 480); }
 
 void FPGAViewWidget::setXTranslation(float t_x)
 {
-    if (t_x != m_xMove) {
-        m_xMove = t_x;
-        update();
-    }
+    if (t_x == moveX_)
+        return;
+
+    moveX_ = t_x;
+    update();
 }
 
 void FPGAViewWidget::setYTranslation(float t_y)
 {
-    if (t_y != m_yMove) {
-        m_yMove = t_y;
-        update();
-    }
+    if (t_y == moveY_)
+        return;
+
+    moveY_ = t_y;
+    update();
 }
 
 void FPGAViewWidget::setZoom(float t_z)
 {
-    if (t_z != m_zDistance) {
-        m_zDistance -= t_z;
-        if (m_zDistance < 0.1f)
-            m_zDistance = 0.1f;
-        if (m_zDistance > 10.0f)
-            m_zDistance = 10.0f;
-
-        update();
-    }
+    if (t_z == zoom_)
+        return;
+    zoom_ = t_z;
+
+    if (zoom_ < 1.0f)
+        zoom_ = 1.0f;
+    if (zoom_ > 100.f)
+        zoom_ = 100.0f;
+
+    update();
 }
 
 void FPGAViewWidget::initializeGL()
 {
+    if (!lineShader_.compile()) {
+        log_error("Could not compile shader.\n");
+    }
     initializeOpenGLFunctions();
     glClearColor(1.0, 1.0, 1.0, 0.0);
 }
 
-void FPGAViewWidget::drawElement(const GraphicElement &el)
+void FPGAViewWidget::drawElement(LineShaderData &out, const GraphicElement &el)
 {
-    float scale = 1.0, offset = 0.0;
-    if (el.type == GraphicElement::G_BOX) {
-        glBegin(GL_LINES);
-        glVertex3f((offset + scale * el.x1), (offset + scale * el.y1), 0.0f);
-        glVertex3f((offset + scale * el.x2), (offset + scale * el.y1), 0.0f);
-
-        glVertex3f((offset + scale * el.x2), (offset + scale * el.y1), 0.0f);
-        glVertex3f((offset + scale * el.x2), (offset + scale * el.y2), 0.0f);
+    const float scale = 1.0, offset = 0.0;
 
-        glVertex3f((offset + scale * el.x2), (offset + scale * el.y2), 0.0f);
-        glVertex3f((offset + scale * el.x1), (offset + scale * el.y2), 0.0f);
-
-        glVertex3f((offset + scale * el.x1), (offset + scale * el.y2), 0.0f);
-        glVertex3f((offset + scale * el.x1), (offset + scale * el.y1), 0.0f);
-        glEnd();
+    if (el.type == GraphicElement::G_BOX) {
+        auto line = PolyLine(true);
+        line.point(offset + scale * el.x1, offset + scale * el.y1);
+        line.point(offset + scale * el.x2, offset + scale * el.y1);
+        line.point(offset + scale * el.x2, offset + scale * el.y2);
+        line.point(offset + scale * el.x1, offset + scale * el.y2);
+        line.build(out);
     }
 
     if (el.type == GraphicElement::G_LINE) {
-        glBegin(GL_LINES);
-        glVertex3f((offset + scale * el.x1), (offset + scale * el.y1), 0.0f);
-        glVertex3f((offset + scale * el.x2), (offset + scale * el.y2), 0.0f);
-        glEnd();
+        PolyLine(offset + scale * el.x1, offset + scale * el.y1,
+                 offset + scale * el.x2, offset + scale * el.y2)
+                .build(out);
     }
 }
 
 void FPGAViewWidget::paintGL()
 {
-    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
-    glLoadIdentity();
-
-    glTranslatef(m_xMove, m_yMove, -10.0);
-    glScalef(m_zDistance, m_zDistance, 0.0f);
-
-    // Grid
-    glColor3f(0.9, 0.9, 0.9);
-    glBegin(GL_LINES);
-    for (float i = -100; i <= 100; i += 0.1) {
-        glVertex3f((float)i, -100.0f, 0.0f);
-        glVertex3f((float)i, 100.0f, 0.0f);
-        glVertex3f(-100.0f, (float)i, 0.0f);
-        glVertex3f(100.0f, (float)i, 0.0f);
-    }
-    glColor3f(0.7, 0.7, 0.7);
-    for (int i = -100; i <= 100; i += 1) {
-        glVertex3f((float)i, -100.0f, 0.0f);
-        glVertex3f((float)i, 100.0f, 0.0f);
-        glVertex3f(-100.0f, (float)i, 0.0f);
-        glVertex3f(100.0f, (float)i, 0.0f);
+    auto gl = QOpenGLContext::currentContext()->functions();
+    const qreal retinaScale = devicePixelRatio();
+    gl->glViewport(0, 0, width() * retinaScale, height() * retinaScale);
+    gl->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+    const float aspect = float(width()) / float(height());
+
+    QMatrix4x4 matrix;
+    matrix.ortho(QRectF(-aspect / 2.0, -0.5, aspect, 1.0f));
+    matrix.translate(moveX_, moveY_, -0.5);
+    matrix.scale(zoom_ * 0.01f, zoom_ * 0.01f, 0);
+
+    // Draw grid.
+    auto grid = LineShaderData(0.01f, QColor("#DDD"));
+    for (float i = -100.0f; i < 100.0f; i += 1.0f) {
+        PolyLine(-100.0f, i, 100.0f, i).build(grid);
+        PolyLine(i, -100.0f, i, 100.0f).build(grid);
     }
-    glEnd();
+    lineShader_.draw(grid, matrix);
 
-    glColor3f(0.1, 0.1, 0.1);
-    glLineWidth(0.1);
-    // Draw Bels
+    // Draw Bels.
+    auto bels = LineShaderData(0.02f, QColor("#b000ba"));
     for (auto bel : ctx->getBels()) {
         for (auto &el : ctx->getBelGraphics(bel))
-            drawElement(el);
+            drawElement(bels, el);
     }
-    // Draw Frame Graphics
-    for (auto &el : ctx->getFrameGraphics())
-        drawElement(el);
-}
+    lineShader_.draw(bels, matrix);
 
-void FPGAViewWidget::resizeGL(int width, int height)
-{
-    m_windowWidth = width;
-    m_windowHeight = height;
-    glViewport(0, 0, m_windowWidth, m_windowHeight);
-
-    float aspect = width * 1.0 / height;
-
-    glMatrixMode(GL_PROJECTION);
-    glLoadIdentity();
-    glOrtho(-1.0 * aspect, +1.0 * aspect, -1.0, +1.0, 1.0, 15.0);
-    glMatrixMode(GL_MODELVIEW);
+    // Draw Frame Graphics.
+    auto frames = LineShaderData(0.02f, QColor("#0066ba"));
+    for (auto &el : ctx->getFrameGraphics()) {
+        drawElement(frames, el);
+    }
+    lineShader_.draw(frames, matrix);
 }
 
+void FPGAViewWidget::resizeGL(int width, int height) {}
+
 void FPGAViewWidget::mousePressEvent(QMouseEvent *event)
 {
-    m_lastPos = event->pos();
+    startDragX_ = moveX_;
+    startDragY_ = moveY_;
+    lastPos_ = event->pos();
 }
 
 void FPGAViewWidget::mouseMoveEvent(QMouseEvent *event)
 {
-    int dx = event->x() - m_lastPos.x();
-    int dy = event->y() - m_lastPos.y();
-    float dx_scale = dx * (1 / (float)640);
-    float dy_scale = -dy * (1 / (float)480);
-
-    if (event->buttons() & Qt::LeftButton) {
-        float xpos = m_xMove + dx_scale;
-        float ypos = m_yMove + dy_scale;
-        if (m_xMove / m_zDistance <= 100.0 && m_xMove / m_zDistance >= -100.0)
-            setXTranslation(xpos);
-        if (m_yMove / m_zDistance <= 100.0 && m_yMove / m_zDistance >= -100.0)
-            setYTranslation(ypos);
-    }
-    m_lastPos = event->pos();
+    const int dx = event->x() - lastPos_.x();
+    const int dy = event->y() - lastPos_.y();
+
+    const qreal retinaScale = devicePixelRatio();
+    float aspect = float(width()) / float(height());
+    const float dx_scale = dx * (1 / (float)width() * retinaScale * aspect);
+    const float dy_scale = dy * (1 / (float)height() * retinaScale);
+
+    float xpos = dx_scale + startDragX_;
+    float ypos = dy_scale + startDragY_;
+
+    setXTranslation(xpos);
+    setYTranslation(ypos);
 }
 
 void FPGAViewWidget::wheelEvent(QWheelEvent *event)
@@ -171,8 +365,8 @@ void FPGAViewWidget::wheelEvent(QWheelEvent *event)
     QPoint degree = event->angleDelta() / 8;
 
     if (!degree.isNull()) {
-        QPoint step = degree / 15;
-        setZoom(step.y() * -0.1f);
+        float steps = degree.y() / 15.0;
+        setZoom(zoom_ + steps);
     }
 }
 
diff --git a/gui/fpgaviewwidget.h b/gui/fpgaviewwidget.h
index fc3ca562..0cfcbb3e 100644
--- a/gui/fpgaviewwidget.h
+++ b/gui/fpgaviewwidget.h
@@ -1,14 +1,205 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Serge Bazanski <q3k@symbioticeda.com>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
 #ifndef MAPGLWIDGET_H
 #define MAPGLWIDGET_H
 
 #include <QMainWindow>
+#include <QOpenGLBuffer>
 #include <QOpenGLFunctions>
+#include <QOpenGLShaderProgram>
 #include <QOpenGLWidget>
 #include <QPainter>
+
 #include "nextpnr.h"
 
 NEXTPNR_NAMESPACE_BEGIN
 
+// Vertex2DPOD is a structure of X, Y coordinates that can be passed to OpenGL
+// directly.
+struct Vertex2DPOD
+{
+    GLfloat x;
+    GLfloat y;
+
+    Vertex2DPOD(GLfloat X, GLfloat Y) : x(X), y(Y) {}
+} __attribute__((packed));
+
+// Vertex2DPOD is a structure of R, G, B, A values that can be passed to OpenGL
+// directly.
+struct ColorPOD
+{
+    GLfloat r;
+    GLfloat g;
+    GLfloat b;
+    GLfloat a;
+
+    ColorPOD(GLfloat R, GLfloat G, GLfloat B, GLfloat A)
+            : r(R), g(G), b(B), a(A)
+    {
+    }
+    ColorPOD(const QColor &color)
+            : r(color.redF()), g(color.greenF()), b(color.blueF()),
+              a(color.alphaF())
+    {
+    }
+} __attribute__((packed));
+
+// LineShaderData is a built set of vertices that can be rendered by the
+// LineShader.
+// Each LineShaderData can have its' own color and thickness.
+struct LineShaderData
+{
+    std::vector<Vertex2DPOD> vertices;
+    std::vector<Vertex2DPOD> normals;
+    std::vector<GLfloat> miters;
+    std::vector<GLuint> indices;
+
+    GLfloat thickness;
+    ColorPOD color;
+
+    LineShaderData(GLfloat Thickness, QColor Color)
+            : thickness(Thickness), color(Color)
+    {
+    }
+};
+
+// PolyLine is a set of segments defined by points, that can be built to a
+// ShaderLine for GPU rendering.
+class PolyLine
+{
+  private:
+    std::vector<QVector2D> points_;
+    bool closed_;
+
+    void buildPoint(LineShaderData *building, const QVector2D *prev,
+                    const QVector2D *cur, const QVector2D *next) const;
+
+  public:
+    // Create an empty PolyLine.
+    PolyLine(bool closed = false) : closed_(closed) {}
+
+    // Create a non-closed polyline consisting of one segment.
+    PolyLine(float x0, float y0, float x1, float y1) : closed_(false)
+    {
+        point(x0, y0);
+        point(x1, y1);
+    }
+
+    // Add a point to the PolyLine.
+    void point(float x, float y) { points_.push_back(QVector2D(x, y)); }
+
+    // Built PolyLine to shader data.
+    void build(LineShaderData &target) const;
+
+    // Set whether line is closed (ie. a loop).
+    void setClosed(bool closed) { closed_ = closed; }
+};
+
+// LineShader is an OpenGL shader program that renders LineShaderData on the
+// GPU.
+// The LineShader expects two vertices per line point. It will push those
+// vertices along the given normal * miter. This is used to 'stretch' the line
+// to be as wide as the given thickness. The normal and miter are calculated
+// by the PolyLine build method in order to construct a constant thickness line
+// with miter edge joints.
+//
+//        +------+------+
+//
+//               |
+//        PolyLine.build()
+//               |
+//               V
+//
+//        ^      ^      ^
+//        |      |      |    <--- normal vectors (x2, pointing in the same
+//       +/+----+/+----+/+        direction)
+//
+//               |
+//         vertex shader
+//               |
+//               V
+//
+//        +------+------+ ^ by normal * miter * thickness/2
+//        |      |      |
+//        +------+------+ V by normal * miter * thickness/2
+//
+//                         (miter is flipped for every second vertex generated)
+class LineShader
+{
+  private:
+    QObject *parent_;
+    QOpenGLShaderProgram *program_;
+
+    // GL attribute locations.
+    struct
+    {
+        // original position of line vertex
+        GLuint position;
+        // normal by which vertex should be translated
+        GLuint normal;
+        // scalar defining:
+        // - how stretched the normal vector should be to
+        //   compensate for bends
+        // - which way the normal should be applied (+1 for one vertex, -1
+        //   for the other)
+        GLuint miter;
+    } attributes_;
+
+    // GL uniform locations.
+    struct
+    {
+        // combines m/v/p matrix to apply
+        GLuint projection;
+        // desired thickness of line
+        GLuint thickness;
+        // color of line
+        GLuint color;
+    } uniforms_;
+
+  public:
+    LineShader(QObject *parent) : parent_(parent), program_(nullptr) {}
+
+    static constexpr const char *vertexShaderSource_ =
+            "attribute highp vec2  position;\n"
+            "attribute highp vec2  normal;\n"
+            "attribute highp float miter;\n"
+            "uniform   highp float thickness;\n"
+            "uniform   highp mat4  projection;\n"
+            "void main() {\n"
+            "   vec2 p = position.xy + vec2(normal * thickness/2.0 / miter);\n"
+            "   gl_Position = projection * vec4(p, 0.0, 1.0);\n"
+            "}\n";
+
+    static constexpr const char *fragmentShaderSource_ =
+            "uniform   lowp  vec4  color;\n"
+            "void main() {\n"
+            "   gl_FragColor = color;\n"
+            "}\n";
+
+    // Must be called on initialization.
+    bool compile(void);
+
+    // Render a LineShaderData with a given M/V/P transformation.
+    void draw(const LineShaderData &data, const QMatrix4x4 &projection);
+};
+
 class FPGAViewWidget : public QOpenGLWidget, protected QOpenGLFunctions
 {
     Q_OBJECT
@@ -35,16 +226,18 @@ class FPGAViewWidget : public QOpenGLWidget, protected QOpenGLFunctions
     void mousePressEvent(QMouseEvent *event) Q_DECL_OVERRIDE;
     void mouseMoveEvent(QMouseEvent *event) Q_DECL_OVERRIDE;
     void wheelEvent(QWheelEvent *event) Q_DECL_OVERRIDE;
-    void drawElement(const GraphicElement &el);
+    void drawElement(LineShaderData &data, const GraphicElement &el);
     QMainWindow *getMainWindow();
 
   private:
-    int m_windowWidth;
-    int m_windowHeight;
-    float m_xMove;
-    float m_yMove;
-    float m_zDistance;
-    QPoint m_lastPos;
+    QPoint lastPos_;
+    float moveX_;
+    float moveY_;
+    float zoom_;
+    LineShader lineShader_;
+
+    float startDragX_;
+    float startDragY_;
     Context *ctx;
 };
 
diff --git a/ice40/chipdb.py b/ice40/chipdb.py
index db8730cf..623cdfce 100644
--- a/ice40/chipdb.py
+++ b/ice40/chipdb.py
@@ -209,7 +209,7 @@ def init_tiletypes(device):
         num_tile_types = 10
     else:
         num_tile_types = 5
-    tile_sizes = {_: (0, 0) for _ in range(num_tile_types)}
+    tile_sizes = {i: (0, 0) for i in range(num_tile_types)}
     tile_bits = [[] for _ in range(num_tile_types)]
 
 with open(sys.argv[1], "r") as f:
diff --git a/ice40/main.cc b/ice40/main.cc
index 8ae9ccf0..ae8c7705 100644
--- a/ice40/main.cc
+++ b/ice40/main.cc
@@ -20,6 +20,7 @@
 #ifdef MAIN_EXECUTABLE
 
 #include <QApplication>
+#include <QSurfaceFormat>
 #include <boost/filesystem/convenience.hpp>
 #include <boost/program_options.hpp>
 #include <fstream>