diff --git a/shaders/world.frag.glsl b/shaders/world.frag.glsl
index 10131f5..9cf47b7 100644
--- a/shaders/world.frag.glsl
+++ b/shaders/world.frag.glsl
@@ -11,8 +11,8 @@ out vec4 outColor;
 void main()
 {
     vec2 halfScreen = screenSize/2;
-    vec2 screenPos = gl_FragCoord.xy/gl_FragCoord.w + camera.xy;
+    vec2 screenPos = gl_FragCoord.xy + camera.xy;
     vec2 texCoord = (screenPos-halfScreen)/200;
-    vec3 texColor = texture(colorMap, texCoord).xyz;
+    vec3 texColor = texelFetch(colorMap, ivec2(screenPos*camera.z)).xyz;
     outColor = vec4(texColor, 1.0);
 }
diff --git a/src/drawwidget.cpp b/src/drawwidget.cpp
index c508127..a620f9c 100644
--- a/src/drawwidget.cpp
+++ b/src/drawwidget.cpp
@@ -14,8 +14,8 @@ DrawWidget::DrawWidget(QWidget *parent) :
     QOpenGLWidget(parent),
     m_Qt_fbo(NULL)
 {
-    connect(&openglRefreshTimer, SIGNAL(timeout()), this, SLOT(repaint()));
-    openglRefreshTimer.start(16);
+    new_simulation = false;
+    update_needed = false;
 }
 
 DrawWidget::~DrawWidget()
@@ -35,9 +35,24 @@ void DrawWidget::initializeGL()
 
 void DrawWidget::paintGL()
 {
+    if(new_simulation)
+    {
+        m_pipeline = new PixelPipeline(m_map);
+        m_pipeline->setTargetFBO(m_Qt_fbo);
+        m_pipeline->resizeGL(m_width, m_height);
+        renderer.setScene(m_map);
+        new_simulation = false;
+    }
+    else if(update_needed)
+        m_pipeline->updateChanges();
     renderer.renderGL();
 }
 
+void DrawWidget::updateDudesBehavior()
+{
+    update_needed = true;
+}
+
 void DrawWidget::resizeGL(int w, int h)
 {
     m_width = w;
@@ -58,12 +73,10 @@ void DrawWidget::startSimulation(GenerateFunction genFunc, std::vector<BehaviorF
         delete m_pipeline;
         m_map = NULL;
     }
-    m_map = new MapScene(behaveFuncs.size(), 200, 100);
+    m_map = new MapScene(behaveFuncs.size(), 300);
     genFunc((Map*)m_map);
-    m_pipeline = new PixelPipeline(m_map);
-    m_pipeline->setTargetFBO(m_Qt_fbo);
-    m_pipeline->resizeGL(m_width, m_height);
-    renderer.setScene(m_map);
+    new_simulation = true;
+    repaint();
 }
 
 // INPUT EVENTS
@@ -71,7 +84,10 @@ void DrawWidget::startSimulation(GenerateFunction genFunc, std::vector<BehaviorF
 void DrawWidget::mouseMoveEvent(QMouseEvent *event)
 {
     if(grabbedMouse)
+    {
         m_pipeline->cameraMove(event->globalX() - lastMousePos.x(), event->globalY() - lastMousePos.y());
+        repaint();
+    }
     lastMousePos = event->globalPos();
 }
 
@@ -108,4 +124,5 @@ void DrawWidget::mouseReleaseEvent(QMouseEvent* event)
 void DrawWidget::wheelEvent(QWheelEvent *event)
 {
     m_pipeline->cameraZoom(event->delta());
+    repaint();
 }
diff --git a/src/drawwidget.h b/src/drawwidget.h
index 484771b..8d4c78c 100644
--- a/src/drawwidget.h
+++ b/src/drawwidget.h
@@ -3,7 +3,6 @@
 
 #include <sparrowrenderer.h>
 #include <QOpenGLWidget>
-#include <QTimer>
 
 #include "map.h"
 #include "team.h"
@@ -18,7 +17,6 @@ class DrawWidget : public QOpenGLWidget
         Q_OBJECT
 
         SparrowRenderer renderer;
-        QTimer openglRefreshTimer;
         
         // camera handling variables
         QPoint lastMousePos;
@@ -28,6 +26,9 @@ class DrawWidget : public QOpenGLWidget
         PixelPipeline *m_pipeline;
         int m_width;
         int m_height;
+
+        bool new_simulation;
+        bool update_needed;
         
     protected:
         // Output
@@ -47,6 +48,7 @@ class DrawWidget : public QOpenGLWidget
         ~DrawWidget();
         
     public slots:
+        void updateDudesBehavior();
         void startSimulation(GenerateFunction, std::vector<BehaviorFunction>);
 };
 
diff --git a/src/libwidget.cpp b/src/libwidget.cpp
index be6594f..839c7e3 100644
--- a/src/libwidget.cpp
+++ b/src/libwidget.cpp
@@ -3,6 +3,7 @@
 
 #include <QDir>
 #include <QLibrary>
+#include <QList>
 
 #ifdef Q_OS_WIN
 #define LIB_SUFFIX "dll"
@@ -31,6 +32,7 @@ void LibWidget::refreshBehaviors()
 {
     while(ui->behaviorsList->count() > 0)
         ui->behaviorsList->takeItem(0);
+    m_behaviorList.clear();
     QDir teamDir(QCoreApplication::applicationDirPath());
     if(teamDir.cd("../teams"))
     {
@@ -59,6 +61,7 @@ void LibWidget::refreshGenerators()
 {
     while(ui->generatorsList->count() > 0)
         ui->generatorsList->takeItem(0);
+    m_genList.clear();
     QDir genDir(QCoreApplication::applicationDirPath());
     if(genDir.cd("../generators"))
     {
@@ -81,13 +84,15 @@ void LibWidget::refreshGenerators()
     }
     else
         emit sendError(QString("ERROR : can't open the generators folder.\n"), 5000);
+    if(!m_genList.empty())
+        ui->generatorsList->item(0)->setSelected(true);
 }
 
 void LibWidget::launchSimulation()
 {
     GenerateFunction genFunc = m_genList[ui->generatorsList->currentRow()];
     std::vector<BehaviorFunction> behaveFuncs;
-    for(QListWidgetItem *item : ui->generatorsList->selectedItems())
+    for(QListWidgetItem *item : ui->behaviorsList->selectedItems())
         behaveFuncs.push_back(m_behaviorList[ui->behaviorsList->row(item)]);
     emit createSimulation(genFunc, behaveFuncs);
 }