diff --git a/TODO b/TODO
index 3c0ec2c..f91f469 100644
--- a/TODO
+++ b/TODO
@@ -1,4 +1,6 @@
 Technology Preview 2 :
+- When adding a texture layer (and maybe clouds), noise components cannot be used (they are always flat).
+- Texture preview is sometimes all black.
 - Render tab previews should not rerender when changing render options.
 - Compute shadows only once for all textures at a same location.
 - Add antialiasing option (pay attention to memory usage).
diff --git a/gui_qt/formtextures.cpp b/gui_qt/formtextures.cpp
index 4dfb0c4..14021a9 100644
--- a/gui_qt/formtextures.cpp
+++ b/gui_qt/formtextures.cpp
@@ -95,6 +95,8 @@ public:
         _renderer.camera_location.y = 20.0;
         _renderer.camera_location.z = 0.0;
         
+        _zone = zoneCreate();
+        
         configScaling(0.1, 10.0, 0.1, 1.0);
         configScrolling(-1000.0, 1000.0, 0.0, -1000.0, 1000.0, 0.0);
     }
@@ -110,6 +112,7 @@ protected:
     void updateData()
     {
         texturesLayerCopyDefinition(&_layer, &_preview_layer);
+        zoneCopy(_zone, _preview_layer.zone);
     }
 private:
     static Color _applyLightingToSurface(Renderer* renderer, Vector3 location, Vector3 normal, SurfaceMaterial material)
@@ -117,6 +120,7 @@ private:
         return lightingApplyToSurface((LightingDefinition*)renderer->customData[0], renderer, location, normal, material);
     }
     
+    Zone* _zone;
     Renderer _renderer;
     TextureLayerDefinition _preview_layer;
     LightingDefinition _lighting;
diff --git a/gui_qt/paysages-qt.pro b/gui_qt/paysages-qt.pro
index ab6e567..d81380c 100644
--- a/gui_qt/paysages-qt.pro
+++ b/gui_qt/paysages-qt.pro
@@ -8,6 +8,7 @@ MOC_DIR = ./moc/$$BUILDMODE/
 DESTDIR = ../build/$$BUILDMODE/
 CONFIG += $$BUILDMODE
 
+LIBS += -lGLU
 unix:LIBS += -L$$DESTDIR -lpaysages
 win32:LIBS += ../libpaysages.a -lDevIL -lILU -lILUT -lglib-2.0 -lgthread-2.0
 
diff --git a/gui_qt/widgetwanderer.cpp b/gui_qt/widgetwanderer.cpp
index 144a223..e41d891 100644
--- a/gui_qt/widgetwanderer.cpp
+++ b/gui_qt/widgetwanderer.cpp
@@ -4,6 +4,7 @@
 #include <QKeyEvent>
 #include <QTime>
 #include <math.h>
+#include <GL/glu.h>
 #include "../lib_paysages/scenery.h"
 
 WidgetWanderer::WidgetWanderer(QWidget *parent, CameraDefinition* camera):
diff --git a/i18n/paysages_fr.ts b/i18n/paysages_fr.ts
index c4b233d..5f0388f 100644
--- a/i18n/paysages_fr.ts
+++ b/i18n/paysages_fr.ts
@@ -499,7 +499,7 @@ Maintenir Ctrl : Plus rapide</translation>
 <context>
     <name>FormTextures</name>
     <message>
-        <location filename="../gui_qt/formtextures.cpp" line="134"/>
+        <location filename="../gui_qt/formtextures.cpp" line="138"/>
         <source>Coverage preview</source>
         <translation>Aperçu de la couverture</translation>
     </message>
@@ -508,77 +508,77 @@ Maintenir Ctrl : Plus rapide</translation>
         <translation type="obsolete">Rendu en couleur</translation>
     </message>
     <message>
-        <location filename="../gui_qt/formtextures.cpp" line="135"/>
+        <location filename="../gui_qt/formtextures.cpp" line="139"/>
         <source>Lighted sample</source>
         <translation>Echantillon éclairé</translation>
     </message>
     <message>
-        <location filename="../gui_qt/formtextures.cpp" line="137"/>
+        <location filename="../gui_qt/formtextures.cpp" line="141"/>
         <source>Surface noise</source>
         <translation>Bruit de surface</translation>
     </message>
     <message>
-        <location filename="../gui_qt/formtextures.cpp" line="138"/>
+        <location filename="../gui_qt/formtextures.cpp" line="142"/>
         <source>Surface noise height</source>
         <translation>Hauteur du bruit</translation>
     </message>
     <message>
-        <location filename="../gui_qt/formtextures.cpp" line="139"/>
+        <location filename="../gui_qt/formtextures.cpp" line="143"/>
         <source>Surface noise scaling</source>
         <translation>Echelle du bruit</translation>
     </message>
     <message>
-        <location filename="../gui_qt/formtextures.cpp" line="140"/>
+        <location filename="../gui_qt/formtextures.cpp" line="144"/>
         <source>Base color</source>
         <translation>Couleur de base</translation>
     </message>
     <message>
-        <location filename="../gui_qt/formtextures.cpp" line="141"/>
+        <location filename="../gui_qt/formtextures.cpp" line="145"/>
         <source>Light reflection</source>
         <translation>Réflexion de lumière</translation>
     </message>
     <message>
-        <location filename="../gui_qt/formtextures.cpp" line="142"/>
+        <location filename="../gui_qt/formtextures.cpp" line="146"/>
         <source>Light reflection shininess</source>
         <translation>Concentration de la lumière réfléchie</translation>
     </message>
     <message>
-        <location filename="../gui_qt/formtextures.cpp" line="145"/>
+        <location filename="../gui_qt/formtextures.cpp" line="149"/>
         <source>Soft minimal height</source>
         <translation>Altitude minimal (adoucie)</translation>
     </message>
     <message>
-        <location filename="../gui_qt/formtextures.cpp" line="144"/>
+        <location filename="../gui_qt/formtextures.cpp" line="148"/>
         <source>Hard minimal height</source>
         <translation>Altitude minimale</translation>
     </message>
     <message>
-        <location filename="../gui_qt/formtextures.cpp" line="147"/>
+        <location filename="../gui_qt/formtextures.cpp" line="151"/>
         <source>Hard maximal height</source>
         <translation>Altitude maximale</translation>
     </message>
     <message>
-        <location filename="../gui_qt/formtextures.cpp" line="146"/>
+        <location filename="../gui_qt/formtextures.cpp" line="150"/>
         <source>Soft maximal height</source>
         <translation>Altitude maximale (adoucie)</translation>
     </message>
     <message>
-        <location filename="../gui_qt/formtextures.cpp" line="149"/>
+        <location filename="../gui_qt/formtextures.cpp" line="153"/>
         <source>Soft minimal slope</source>
         <translation>Pente minimale (adoucie)</translation>
     </message>
     <message>
-        <location filename="../gui_qt/formtextures.cpp" line="148"/>
+        <location filename="../gui_qt/formtextures.cpp" line="152"/>
         <source>Hard minimal slope</source>
         <translation>Pente minimale</translation>
     </message>
     <message>
-        <location filename="../gui_qt/formtextures.cpp" line="151"/>
+        <location filename="../gui_qt/formtextures.cpp" line="155"/>
         <source>Hard maximal slope</source>
         <translation>Pente maximale</translation>
     </message>
     <message>
-        <location filename="../gui_qt/formtextures.cpp" line="150"/>
+        <location filename="../gui_qt/formtextures.cpp" line="154"/>
         <source>Soft maximal slope</source>
         <translation>Pente maximale (adoucie)</translation>
     </message>
diff --git a/lib_paysages/render.c b/lib_paysages/render.c
index 1955403..6cf535c 100644
--- a/lib_paysages/render.c
+++ b/lib_paysages/render.c
@@ -33,7 +33,7 @@ struct RenderArea
     RenderCallbackUpdate callback_update;
 };
 
-/*#define RENDER_INVERSE 1*/
+#define RENDER_INVERSE 1
 #define RENDER_WIREFRAME 1
 
 static void _callbackStart(int width, int height, Color background) {}
diff --git a/lib_paysages/shared/types.h b/lib_paysages/shared/types.h
index 0905215..e021adc 100644
--- a/lib_paysages/shared/types.h
+++ b/lib_paysages/shared/types.h
@@ -86,8 +86,6 @@ typedef struct
     double shininess;
 } SurfaceMaterial;
 
-typedef struct Zone Zone;
-
 typedef void (*RenderCallbackStart)(int width, int height, Color background);
 typedef void (*RenderCallbackDraw)(int x, int y, Color col);
 typedef void (*RenderCallbackUpdate)(double progress);
diff --git a/lib_paysages/textures.h b/lib_paysages/textures.h
index 07feb73..ec87f5e 100644
--- a/lib_paysages/textures.h
+++ b/lib_paysages/textures.h
@@ -5,6 +5,7 @@
 #include "noise.h"
 #include "lighting.h"
 #include "pack.h"
+#include "zone.h"
 
 #ifdef __cplusplus
 extern "C" {
diff --git a/lib_paysages/zone.h b/lib_paysages/zone.h
index 45a31d0..c9c4b25 100644
--- a/lib_paysages/zone.h
+++ b/lib_paysages/zone.h
@@ -8,6 +8,8 @@
 extern "C" {
 #endif
 
+typedef struct Zone Zone;
+
 typedef struct
 {
     double value;