diff --git a/Alpha_shapes_3/demo/Alpha_shapes_3/Viewer.cpp b/Alpha_shapes_3/demo/Alpha_shapes_3/Viewer.cpp
index e903ab64bea..9069e592943 100644
--- a/Alpha_shapes_3/demo/Alpha_shapes_3/Viewer.cpp
+++ b/Alpha_shapes_3/demo/Alpha_shapes_3/Viewer.cpp
@@ -51,24 +51,24 @@ void Viewer::compile_shaders()
         "varying highp vec4 fP; \n"
         "varying highp vec3 fN; \n"
         "uniform highp vec4 color; \n"
-        "uniform vec4 light_pos;  \n"
-        "uniform vec4 light_diff; \n"
-        "uniform vec4 light_spec; \n"
-        "uniform vec4 light_amb;  \n"
+        "uniform highp vec4 light_pos;  \n"
+        "uniform highp vec4 light_diff; \n"
+        "uniform highp vec4 light_spec; \n"
+        "uniform highp vec4 light_amb;  \n"
         "uniform float spec_power ; \n"
 
         "void main(void) { \n"
 
-        "   vec3 L = light_pos.xyz - fP.xyz; \n"
-        "   vec3 V = -fP.xyz; \n"
+        "   highp vec3 L = light_pos.xyz - fP.xyz; \n"
+        "   highp vec3 V = -fP.xyz; \n"
 
-        "   vec3 N = normalize(fN); \n"
+        "   highp vec3 N = normalize(fN); \n"
         "   L = normalize(L); \n"
         "   V = normalize(V); \n"
 
-        "   vec3 R = reflect(-L, N); \n"
-        "   vec4 diffuse = abs(dot(N,L)) * light_diff * color; \n"
-        "   vec4 specular = pow(max(dot(R,V), 0.0), spec_power) * light_spec; \n"
+        "   highp vec3 R = reflect(-L, N); \n"
+        "   highp vec4 diffuse = abs(dot(N,L)) * light_diff * color; \n"
+        "   highp vec4 specular = pow(max(dot(R,V), 0.0), spec_power) * light_spec; \n"
 
         "gl_FragColor = light_amb*color + diffuse + specular ; \n"
         "} \n"
diff --git a/Circular_kernel_3/demo/Circular_kernel_3/Viewer.cpp b/Circular_kernel_3/demo/Circular_kernel_3/Viewer.cpp
index 2e53e260c8a..6cb777920fc 100644
--- a/Circular_kernel_3/demo/Circular_kernel_3/Viewer.cpp
+++ b/Circular_kernel_3/demo/Circular_kernel_3/Viewer.cpp
@@ -56,24 +56,24 @@ void Viewer::compile_shaders()
         "varying highp vec4 fP; \n"
         "varying highp vec3 fN; \n"
         "uniform highp vec4 color; \n"
-        "uniform vec4 light_pos;  \n"
-        "uniform vec4 light_diff; \n"
-        "uniform vec4 light_spec; \n"
-        "uniform vec4 light_amb;  \n"
+        "uniform highp vec4 light_pos;  \n"
+        "uniform highp vec4 light_diff; \n"
+        "uniform highp vec4 light_spec; \n"
+        "uniform highp vec4 light_amb;  \n"
         "uniform float spec_power ; \n"
 
         "void main(void) { \n"
 
-        "   vec3 L = light_pos.xyz - fP.xyz; \n"
-        "   vec3 V = -fP.xyz; \n"
+        "   highp vec3 L = light_pos.xyz - fP.xyz; \n"
+        "   highp vec3 V = -fP.xyz; \n"
 
-        "   vec3 N = normalize(fN); \n"
+        "   highp vec3 N = normalize(fN); \n"
         "   L = normalize(L); \n"
         "   V = normalize(V); \n"
 
-        "   vec3 R = reflect(-L, N); \n"
-        "   vec4 diffuse = max(dot(N,L), 0.0) * light_diff * color; \n"
-        "   vec4 specular = pow(max(dot(R,V), 0.0), spec_power) * light_spec; \n"
+        "   highp vec3 R = reflect(-L, N); \n"
+        "   highp vec4 diffuse = max(dot(N,L), 0.0) * light_diff * color; \n"
+        "   highp vec4 specular = pow(max(dot(R,V), 0.0), spec_power) * light_spec; \n"
 
         "gl_FragColor = light_amb*color + diffuse  ; \n"
         "} \n"
diff --git a/GraphicsView/include/CGAL/Qt/Basic_viewer_qt.h b/GraphicsView/include/CGAL/Qt/Basic_viewer_qt.h
index 1d2fbd751e9..8b23594cd7c 100644
--- a/GraphicsView/include/CGAL/Qt/Basic_viewer_qt.h
+++ b/GraphicsView/include/CGAL/Qt/Basic_viewer_qt.h
@@ -93,24 +93,24 @@ const char fragment_source_color[] =
     "varying highp vec4 fP; \n"
     "varying highp vec3 fN; \n"
     "varying highp vec4 fColor; \n"
-    "uniform vec4 light_pos;  \n"
-    "uniform vec4 light_diff; \n"
-    "uniform vec4 light_spec; \n"
-    "uniform vec4 light_amb;  \n"
+    "uniform highp vec4 light_pos;  \n"
+    "uniform highp vec4 light_diff; \n"
+    "uniform highp vec4 light_spec; \n"
+    "uniform highp vec4 light_amb;  \n"
     "uniform float spec_power ; \n"
     
     "void main(void) { \n"
     
-    "   vec3 L = light_pos.xyz - fP.xyz; \n"
-    "   vec3 V = -fP.xyz; \n"
+    "   highp vec3 L = light_pos.xyz - fP.xyz; \n"
+    "   highp vec3 V = -fP.xyz; \n"
     
-    "   vec3 N = normalize(fN); \n"
+    "   highp vec3 N = normalize(fN); \n"
     "   L = normalize(L); \n"
     "   V = normalize(V); \n"
     
-    "   vec3 R = reflect(-L, N); \n"
-    "   vec4 diffuse = max(dot(N,L), 0.0) * light_diff * fColor; \n"
-    "   vec4 specular = pow(max(dot(R,V), 0.0), spec_power) * light_spec; \n"
+    "   highp vec3 R = reflect(-L, N); \n"
+    "   highp vec4 diffuse = max(dot(N,L), 0.0) * light_diff * fColor; \n"
+    "   highp vec4 specular = pow(max(dot(R,V), 0.0), spec_power) * light_spec; \n"
     
     "gl_FragColor = light_amb*fColor + diffuse  ; \n"
     "} \n"
@@ -142,6 +142,93 @@ const char fragment_source_p_l[] =
     "} \n"
     "\n"
   };
+
+//------------------------------------------------------------------------------
+//  compatibility shaders
+
+const char vertex_source_color_comp[] =
+  {
+    "attribute highp vec4 vertex;\n"
+    "attribute highp vec3 normal;\n"
+    "attribute highp vec3 color;\n"
+    
+    "uniform highp mat4 mvp_matrix;\n"
+    "uniform highp mat4 mv_matrix; \n"
+    
+    "varying highp vec4 fP; \n"
+    "varying highp vec3 fN; \n"
+    "varying highp vec4 fColor; \n"
+    
+    "uniform highp float point_size; \n"
+    "void main(void)\n"
+    "{\n"
+    "   fP = mv_matrix * vertex; \n"
+    "   highp mat3 mv_matrix_3; \n"
+    "   mv_matrix_3[0] = mv_matrix[0].xyz; \n"
+    "   mv_matrix_3[1] = mv_matrix[1].xyz; \n"
+    "   mv_matrix_3[2] = mv_matrix[2].xyz; \n"
+    "   fN = mv_matrix_3* normal;  \n"
+    "   fColor = vec4(color, 1.0); \n"
+    "   gl_PointSize = point_size;\n"
+    "   gl_Position = mvp_matrix * vertex;\n"
+    "}"
+  };
+
+const char fragment_source_color_comp[] =
+  {
+    "varying highp vec4 fP; \n"
+    "varying highp vec3 fN; \n"
+    "varying highp vec4 fColor; \n"
+    "uniform highp vec4 light_pos;  \n"
+    "uniform highp vec4 light_diff; \n"
+    "uniform highp vec4 light_spec; \n"
+    "uniform highp vec4 light_amb;  \n"
+    "uniform highp float spec_power ; \n"
+    
+    "void main(void) { \n"
+    
+    "   highp vec3 L = light_pos.xyz - fP.xyz; \n"
+    "   highp vec3 V = -fP.xyz; \n"
+    
+    "   highp vec3 N = normalize(fN); \n"
+    "   L = normalize(L); \n"
+    "   V = normalize(V); \n"
+    
+    "   highp vec3 R = reflect(-L, N); \n"
+    "   highp vec4 diffuse = max(dot(N,L), 0.0) * light_diff * fColor; \n"
+    "   highp vec4 specular = pow(max(dot(R,V), 0.0), spec_power) * light_spec; \n"
+    
+    "gl_FragColor = light_amb*fColor + diffuse  ; \n"
+    "} \n"
+    "\n"
+  };
+
+const char vertex_source_p_l_comp[] =
+  {
+    "attribute highp vec4 vertex;\n"
+    "attribute highp vec3 color;\n"
+    "uniform highp mat4 mvp_matrix;\n"
+    "varying highp vec4 fColor; \n"
+    "uniform highp float point_size; \n"
+    "void main(void)\n"
+    "{\n"
+    "   gl_PointSize = point_size;\n"
+    "   fColor = vec4(color, 1.0); \n"
+    "   gl_Position = mvp_matrix * vertex;\n"
+    "}"
+  };
+
+const char fragment_source_p_l_comp[] =
+  {
+    "varying highp vec4 fColor; \n"
+    "void main(void) { \n"
+    "gl_FragColor = fColor; \n"
+    "} \n"
+    "\n"
+  };
+
+
+
 //------------------------------------------------------------------------------
 inline CGAL::Color get_random_color(CGAL::Random& random)
 {
@@ -378,12 +465,21 @@ protected:
     }
     
     // Vertices and segments shader
+    
+    const char* source_ = isOpenGL_4_3() 
+        ? vertex_source_p_l
+        : vertex_source_p_l_comp;
+    
     QOpenGLShader *vertex_shader_p_l = new QOpenGLShader(QOpenGLShader::Vertex);
-    if(!vertex_shader_p_l->compileSourceCode(vertex_source_p_l))
+    if(!vertex_shader_p_l->compileSourceCode(source_))
     { std::cerr<<"Compiling vertex source FAILED"<<std::endl; }
 
+    source_ = isOpenGL_4_3() 
+        ? fragment_source_p_l
+        : fragment_source_p_l_comp;
+    
     QOpenGLShader *fragment_shader_p_l= new QOpenGLShader(QOpenGLShader::Fragment);
-    if(!fragment_shader_p_l->compileSourceCode(fragment_source_p_l))
+    if(!fragment_shader_p_l->compileSourceCode(source_))
     { std::cerr<<"Compiling fragmentsource FAILED"<<std::endl; }
 
     if(!rendering_program_p_l.addShader(vertex_shader_p_l))
@@ -394,12 +490,21 @@ protected:
     { std::cerr<<"linking Program FAILED"<<std::endl; }
 
     // Faces shader
+    
+    source_ = isOpenGL_4_3() 
+            ? vertex_source_color
+            : vertex_source_color_comp;
+    
     QOpenGLShader *vertex_shader_face = new QOpenGLShader(QOpenGLShader::Vertex);
-    if(!vertex_shader_face->compileSourceCode(vertex_source_color))
+    if(!vertex_shader_face->compileSourceCode(source_))
     { std::cerr<<"Compiling vertex source FAILED"<<std::endl; }
 
+    source_ = isOpenGL_4_3() 
+            ? fragment_source_color
+            : fragment_source_color_comp;
+    
     QOpenGLShader *fragment_shader_face= new QOpenGLShader(QOpenGLShader::Fragment);
-    if(!fragment_shader_face->compileSourceCode(fragment_source_color))
+    if(!fragment_shader_face->compileSourceCode(source_))
     { std::cerr<<"Compiling fragmentsource FAILED"<<std::endl; }
 
     if(!rendering_program_face.addShader(vertex_shader_face))
diff --git a/GraphicsView/include/CGAL/Qt/qglviewer_impl.h b/GraphicsView/include/CGAL/Qt/qglviewer_impl.h
index 311093c8283..8e3addda3d7 100644
--- a/GraphicsView/include/CGAL/Qt/qglviewer_impl.h
+++ b/GraphicsView/include/CGAL/Qt/qglviewer_impl.h
@@ -452,18 +452,18 @@ void CGAL::QGLViewer::initializeGL() {
       "   highp vec4 light_spec = vec4(0.0, 0.0, 0.0, 1.0); \n"
       "   highp vec4 light_amb = vec4(0.4, 0.4, 0.4, 0.4);  \n"
       "   highp float spec_power = 51.8 ; \n"
-      "   vec3 L = light_pos.xyz - fP.xyz; \n"
-      "   vec3 V = -fP.xyz; \n"
-      "   vec3 N; \n"
+      "   highp vec3 L = light_pos.xyz - fP.xyz; \n"
+      "   highp vec3 V = -fP.xyz; \n"
+      "   highp vec3 N; \n"
       "   if(fN == vec3(0.0,0.0,0.0)) \n"
       "       N = vec3(0.0,0.0,0.0); \n"
       "   else \n"
       "       N = normalize(fN); \n"
       "   L = normalize(L); \n"
       "   V = normalize(V); \n"
-      "   vec3 R = reflect(-L, N); \n"
-      "   vec4 diffuse = max(abs(dot(N,L)),0.0) * light_diff*color; \n"
-      "   vec4 specular = pow(max(dot(R,V), 0.0), spec_power) * light_spec; \n"
+      "   highp vec3 R = reflect(-L, N); \n"
+      "   highp vec4 diffuse = max(abs(dot(N,L)),0.0) * light_diff*color; \n"
+      "   highp vec4 specular = pow(max(dot(R,V), 0.0), spec_power) * light_spec; \n"
       
       "gl_FragColor = color*light_amb + diffuse + specular; \n"
       "gl_FragColor = vec4(gl_FragColor.xyz, 1.0); \n"
diff --git a/Linear_cell_complex/examples/Linear_cell_complex/basic_viewer.h b/Linear_cell_complex/examples/Linear_cell_complex/basic_viewer.h
index 3dea72672c8..0ca4f962109 100644
--- a/Linear_cell_complex/examples/Linear_cell_complex/basic_viewer.h
+++ b/Linear_cell_complex/examples/Linear_cell_complex/basic_viewer.h
@@ -97,24 +97,24 @@ const char fragment_source_mono[] =
     "varying highp vec4 fP; \n"
     "varying highp vec3 fN; \n"
     "uniform highp vec4 color; \n"
-    "uniform vec4 light_pos;  \n"
-    "uniform vec4 light_diff; \n"
-    "uniform vec4 light_spec; \n"
-    "uniform vec4 light_amb;  \n"
+    "uniform highp vec4 light_pos;  \n"
+    "uniform highp vec4 light_diff; \n"
+    "uniform highp vec4 light_spec; \n"
+    "uniform highp vec4 light_amb;  \n"
     "uniform float spec_power ; \n"
     
     "void main(void) { \n"
     
-    "   vec3 L = light_pos.xyz - fP.xyz; \n"
-    "   vec3 V = -fP.xyz; \n"
+    "   highp vec3 L = light_pos.xyz - fP.xyz; \n"
+    "   highp vec3 V = -fP.xyz; \n"
     
-    "   vec3 N = normalize(fN); \n"
+    "   highp vec3 N = normalize(fN); \n"
     "   L = normalize(L); \n"
     "   V = normalize(V); \n"
     
-    "   vec3 R = reflect(-L, N); \n"
-    "   vec4 diffuse = max(dot(N,L), 0.0) * light_diff * color; \n"
-    "   vec4 specular = pow(max(dot(R,V), 0.0), spec_power) * light_spec; \n"
+    "   highp vec3 R = reflect(-L, N); \n"
+    "   highp vec4 diffuse = max(dot(N,L), 0.0) * light_diff * color; \n"
+    "   highp vec4 specular = pow(max(dot(R,V), 0.0), spec_power) * light_spec; \n"
     
     "gl_FragColor = light_amb*color + diffuse  ; \n"
     "} \n"
@@ -127,24 +127,24 @@ const char fragment_source_color[] =
     "varying highp vec4 fP; \n"
     "varying highp vec3 fN; \n"
     "varying highp vec4 fColor; \n"
-    "uniform vec4 light_pos;  \n"
-    "uniform vec4 light_diff; \n"
-    "uniform vec4 light_spec; \n"
-    "uniform vec4 light_amb;  \n"
+    "uniform highp vec4 light_pos;  \n"
+    "uniform highp vec4 light_diff; \n"
+    "uniform highp vec4 light_spec; \n"
+    "uniform highp vec4 light_amb;  \n"
     "uniform float spec_power ; \n"
     
     "void main(void) { \n"
     
-    "   vec3 L = light_pos.xyz - fP.xyz; \n"
-    "   vec3 V = -fP.xyz; \n"
+    "   highp vec3 L = light_pos.xyz - fP.xyz; \n"
+    "   highp vec3 V = -fP.xyz; \n"
     
-    "   vec3 N = normalize(fN); \n"
+    "   highp vec3 N = normalize(fN); \n"
     "   L = normalize(L); \n"
     "   V = normalize(V); \n"
     
-    "   vec3 R = reflect(-L, N); \n"
-    "   vec4 diffuse = max(dot(N,L), 0.0) * light_diff * fColor; \n"
-    "   vec4 specular = pow(max(dot(R,V), 0.0), spec_power) * light_spec; \n"
+    "   highp vec3 R = reflect(-L, N); \n"
+    "   highp vec4 diffuse = max(dot(N,L), 0.0) * light_diff * fColor; \n"
+    "   highp vec4 specular = pow(max(dot(R,V), 0.0), spec_power) * light_spec; \n"
     
     "gl_FragColor = light_amb*fColor + diffuse  ; \n"
     "} \n"
diff --git a/Periodic_3_triangulation_3/demo/Periodic_3_triangulation_3/Scene.cpp b/Periodic_3_triangulation_3/demo/Periodic_3_triangulation_3/Scene.cpp
index b4c03f43eb9..112f842f499 100644
--- a/Periodic_3_triangulation_3/demo/Periodic_3_triangulation_3/Scene.cpp
+++ b/Periodic_3_triangulation_3/demo/Periodic_3_triangulation_3/Scene.cpp
@@ -143,16 +143,16 @@ void Scene::compile_shaders()
 
         "void main(void) { \n"
 
-        "   vec3 L = light_pos.xyz - fP.xyz; \n"
-        "   vec3 V = -fP.xyz; \n"
+        "   highp vec3 L = light_pos.xyz - fP.xyz; \n"
+        "   highp vec3 V = -fP.xyz; \n"
 
-        "   vec3 N = normalize(fN); \n"
+        "   highp vec3 N = normalize(fN); \n"
         "   L = normalize(L); \n"
         "   V = normalize(V); \n"
 
-        "   vec3 R = reflect(-L, N); \n"
-        "   vec4 diffuse = abs(dot(N,L)) * light_diff; \n"
-        "   vec4 specular = pow(max(dot(R,V), 0.0), spec_power) * light_spec; \n"
+        "   highp vec3 R = reflect(-L, N); \n"
+        "   highp vec4 diffuse = abs(dot(N,L)) * light_diff; \n"
+        "   highp vec4 specular = pow(max(dot(R,V), 0.0), spec_power) * light_spec; \n"
 
         "gl_FragColor = light_amb + diffuse + specular; \n"
         "} \n"
@@ -205,7 +205,7 @@ void Scene::compile_shaders()
         "void main(void)\n"
         "{\n"
         "   fP = mv_matrix * vertex; \n"
-        "   vec4 TN = transfo*vec4(normal,1.0); \n"
+        "   highp vec4 TN = transfo*vec4(normal,1.0); \n"
         "   fN = mat3(mv_matrix)* TN.xyz; \n"
         "   gl_Position =  mvp_matrix * transfo * vertex; \n"
         "}"
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/heat_intensity_shader.frag b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/heat_intensity_shader.frag
index fc327feaca6..3494f9928c2 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/heat_intensity_shader.frag
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/heat_intensity_shader.frag
@@ -1,9 +1,9 @@
-#version 120
+
 varying highp vec4 color;
 varying highp float out_dist;
 void main(void) {
-  vec3 c = color.xyz;
-  float h = out_dist;
+  highp vec3 c = color.xyz;
+  highp float h = out_dist;
   h = h * 20.;
   h = h - floor(h);
   h = (1./(1.+exp(-100.*(h-.55)))) + (1./(1.+exp(-100.*(-h+.45))));
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/heat_intensity_shader.vert b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/heat_intensity_shader.vert
index 732caf2c58c..c8f65a827cc 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/heat_intensity_shader.vert
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/heat_intensity_shader.vert
@@ -1,4 +1,4 @@
-#version 120
+
 attribute highp vec4 vertex;
 attribute highp vec3 normals;
 attribute highp vec3 colors;
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_c3t3.frag b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_c3t3.frag
index f3da3d3d0e9..251ae415a18 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_c3t3.frag
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_c3t3.frag
@@ -1,4 +1,4 @@
-#version 120
+
 varying highp vec4 color;
 varying highp vec4 fP; 
 varying highp vec3 fN; 
@@ -35,24 +35,24 @@ void main(void) {
     if(color.w<0)
     {
 
-      vec4 my_color = vec4(color.xyz, 1.);
+      highp vec4 my_color = vec4(color.xyz, 1.);
       highp vec3 L = light_pos.xyz - fP.xyz; 
       highp vec3 V = -fP.xyz; 
       highp vec3 N; 
-      if(fN == highp vec3(0.0,0.0,0.0))
-          N = highp vec3(0.0,0.0,0.0); 
+      if(fN == vec3(0.0,0.0,0.0))
+          N = vec3(0.0,0.0,0.0);
       else 
           N = normalize(fN); 
       L = normalize(L); 
       V = normalize(V); 
       highp vec3 R = reflect(-L, N); 
-      vec4 diffuse; 
+      highp vec4 diffuse;
       if(is_two_side == 1) 
           diffuse = abs(dot(N,L)) * light_diff * my_color; 
       else 
           diffuse = max(dot(N,L), 0.0) * light_diff * my_color; 
       highp vec4 specular = pow(max(dot(R,V), 0.0), spec_power) * light_spec; 
-      vec4 ret_color = vec4((my_color*light_amb).xyz + diffuse.xyz + specular.xyz,1); 
+      highp vec4 ret_color = vec4((my_color*light_amb).xyz + diffuse.xyz + specular.xyz,1);
       if(is_selected)
           gl_FragColor = vec4(ret_color.r+70.0/255.0, ret_color.g+70.0/255.0, ret_color.b+70.0/255.0, alpha);
       else
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_c3t3_edges.frag b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_c3t3_edges.frag
index 40c1e0e34ff..24fa8d08dc5 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_c3t3_edges.frag
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_c3t3_edges.frag
@@ -1,4 +1,4 @@
-#version 120
+
 varying highp vec4 color;
 void main(void) 
 { 
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_c3t3_spheres.vert b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_c3t3_spheres.vert
index 1ce5c173d76..26b307888a0 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_c3t3_spheres.vert
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_c3t3_spheres.vert
@@ -15,7 +15,7 @@ void main(void)
 {
   gl_PointSize = point_size;
   color = vec4(colors, center.x * cutplane.x  + center.y * cutplane.y  + center.z * cutplane.z  +  cutplane.w);
-  vec4 my_vertex = vec4(radius*vertex.x + center.x, radius* vertex.y + center.y, radius*vertex.z + center.z, 1.0) ;
+  highp vec4 my_vertex = vec4(radius*vertex.x + center.x, radius* vertex.y + center.y, radius*vertex.z + center.z, 1.0) ;
   fP = mv_matrix * my_vertex;
   mat3 mv_matrix_3;                    
   mv_matrix_3[0] = mv_matrix[0].xyz;   
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_instanced.vert b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_instanced.vert
index 1aea0be7347..b8a6ecdaa54 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_instanced.vert
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_instanced.vert
@@ -15,7 +15,7 @@ void main(void)
 {
   gl_PointSize = point_size;
   color = vec4(colors, 1.0);
-  vec4 my_vertex = vec4(vertex.x + center.x, vertex.y + center.y, vertex.z + center.z, 1.0);
+  highp vec4 my_vertex = vec4(vertex.x + center.x, vertex.y + center.y, vertex.z + center.z, 1.0);
   fP = mv_matrix * my_vertex;
   mat3 mv_matrix_3;                    
   mv_matrix_3[0] = mv_matrix[0].xyz;   
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_no_light_no_selection.frag b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_no_light_no_selection.frag
index 48858e1ff6c..711f17d8c8e 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_no_light_no_selection.frag
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_no_light_no_selection.frag
@@ -1,4 +1,4 @@
-#version 120
+
 varying highp vec4 color;
 varying highp float dist[6];
 uniform bool is_clipbox_on;
@@ -13,5 +13,5 @@ if(is_clipbox_on)
      dist[4]>0.0 ||
      dist[5]>0.0)
     discard;
-  gl_FragColor = highp vec4(color.xyz, alpha); 
+  gl_FragColor = vec4(color.xyz, alpha);
 }  
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_old_flat.frag b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_old_flat.frag
index 3326e4225af..bcb5d361280 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_old_flat.frag
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_old_flat.frag
@@ -1,4 +1,4 @@
-#version 120
+
 varying highp vec4 color;
 varying highp vec4 fP;
 uniform highp vec4 light_pos;
@@ -12,24 +12,24 @@ void main(void) {
    highp vec3 L = light_pos.xyz - fP.xyz;
    highp vec3 V = -fP.xyz;
    highp vec3 N;
-   vec3 X = dFdx(fP.xyz);
-   vec3 Y = dFdy(fP.xyz);
-   vec3 normal=normalize(cross(X,Y));
+   highp vec3 X = dFdx(fP.xyz);
+   highp vec3 Y = dFdy(fP.xyz);
+   highp vec3 normal=normalize(cross(X,Y));
 
-   if(normal == highp vec3(0.0,0.0,0.0))
-       N = highp vec3(0.0,0.0,0.0);
+   if(normal == vec3(0.0,0.0,0.0))
+       N = vec3(0.0,0.0,0.0);
    else
        N = normalize(normal);
    L = normalize(L);
    V = normalize(V);
    highp vec3 R = reflect(-L, N);
-  vec4 diffuse;
+  highp vec4 diffuse;
    if(is_two_side == 1)
        diffuse = abs(dot(N,L)) * light_diff * color;
    else
        diffuse = max(dot(N,L), 0.0) * light_diff * color;
    highp vec4 specular = pow(max(dot(R,V), 0.0), spec_power) * light_spec;
-   vec4 ret_color = vec4((color*light_amb).xyz + diffuse.xyz + specular.xyz,1);
+   highp vec4 ret_color = vec4((color*light_amb).xyz + diffuse.xyz + specular.xyz,1);
    if(is_selected)
        gl_FragColor = vec4(ret_color.r+70.0/255.0, ret_color.g+70.0/255.0, ret_color.b+70.0/255.0, 1.0);
    else
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_plane_two_faces.frag b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_plane_two_faces.frag
index 8c6a9a38251..a5986527e8e 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_plane_two_faces.frag
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_plane_two_faces.frag
@@ -1,4 +1,4 @@
-#version 120
+
 varying highp vec4 color;
 uniform highp vec3 dirView;
 uniform highp vec3 plane_normal;
@@ -7,7 +7,7 @@ uniform bool is_selected;
 
 void main(void) {
 highp vec4 t_color = color;
-highp vec3 dir = highp vec3(plane_pos.x - dirView.x, plane_pos.y - dirView.y, plane_pos.z - dirView.z);
+highp vec3 dir = vec3(plane_pos.x - dirView.x, plane_pos.y - dirView.y, plane_pos.z - dirView.z);
 if(dot(dir, plane_normal)>0.0)
   t_color = vec4(1.0-color.r, 1.0-color.g, 1.0-color.b, color.a);
 if(is_selected)
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_light.frag b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_light.frag
index 43c775cbcdb..2c0b38aa039 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_light.frag
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_light.frag
@@ -1,4 +1,4 @@
-#version 120
+
 varying highp vec4 color;
 varying highp vec4 fP;
 varying highp vec3 fN;
@@ -44,18 +44,18 @@ void main(void) {
     gl_FragColor = vec4(d,d,d,1.0);
   else
   {
-    vec4 my_color = vec4(color.xyz, 1.0);
+    highp vec4 my_color = vec4(color.xyz, 1.0);
     highp vec3 L = light_pos.xyz - fP.xyz;
     highp vec3 V = -fP.xyz;
     highp vec3 N;
-    if(fN == highp vec3(0.0,0.0,0.0))
-      N = highp vec3(0.0,0.0,0.0);
+    if(fN == vec3(0.0,0.0,0.0))
+      N = vec3(0.0,0.0,0.0);
     else
       N = normalize(fN);
     L = normalize(L);
     V = normalize(V);
     highp vec3 R = reflect(-L, N);
-    vec4 diffuse;
+    highp vec4 diffuse;
     if(is_two_side == 1)
       diffuse = abs(dot(N,L)) * light_diff * color;
     else
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_texture.frag b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_texture.frag
index 79034e2fcd6..8d398d7c6ef 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_texture.frag
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_texture.frag
@@ -1,4 +1,4 @@
-#version 120
+
 varying highp vec3 fColors;
 varying highp vec2 f_texCoord; 
 uniform sampler2D s_texture; 
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_texture.vert b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_texture.vert
index 811ce461ffd..e73931212fa 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_texture.vert
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_texture.vert
@@ -19,21 +19,21 @@ uniform highp float point_size;
 void main(void)
 {
   gl_PointSize = point_size;
-   vec4 P = mv_matrix * vertex; 
-   mat3 mv_matrix_3;                    
-   mv_matrix_3[0] = mv_matrix[0].xyz;   
-   mv_matrix_3[1] = mv_matrix[1].xyz;   
-   mv_matrix_3[2] = mv_matrix[2].xyz;   
-   vec3 N = mv_matrix_3* normals; 
-   vec3 L = light_pos.xyz - P.xyz; 
-   N = normalize(N); 
-   L = normalize(L); 
-   vec3 diffuse;
-   if(is_two_side == 1) 
-       diffuse = abs(dot(N,L)) * light_diff.xyz; 
-   else 
-       diffuse = max(dot(N,L), 0.0) * light_diff.xyz; 
-   f_texCoord = v_texCoord; 
-   fColors = vec3(1.0, 1.0, 1.0) * (light_amb.xyz + diffuse);
-   gl_Position =  mvp_matrix * f_matrix * vertex; 
+  highp vec4 P = mv_matrix * vertex;
+  mat3 mv_matrix_3;
+  mv_matrix_3[0] = mv_matrix[0].xyz;
+  mv_matrix_3[1] = mv_matrix[1].xyz;
+  mv_matrix_3[2] = mv_matrix[2].xyz;
+  highp vec3 N = mv_matrix_3* normals;
+  highp vec3 L = light_pos.xyz - P.xyz;
+  N = normalize(N);
+  L = normalize(L);
+  highp vec3 diffuse;
+  if(is_two_side == 1)
+      diffuse = abs(dot(N,L)) * light_diff.xyz;
+  else
+      diffuse = max(dot(N,L), 0.0) * light_diff.xyz;
+  f_texCoord = v_texCoord;
+  fColors = vec3(1.0, 1.0, 1.0) * (light_amb.xyz + diffuse);
+  gl_Position =  mvp_matrix * f_matrix * vertex;
 }  
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_textured_edges.frag b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_textured_edges.frag
index eb35fed7437..3d006822334 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_textured_edges.frag
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_with_textured_edges.frag
@@ -1,4 +1,4 @@
-#version 120
+
 varying highp vec3 fColors;
 varying highp vec2 f_texCoord; 
 uniform highp sampler2D s_texture; 
diff --git a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_without_light.frag b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_without_light.frag
index 37a2143398c..57a1c4661a1 100644
--- a/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_without_light.frag
+++ b/Polyhedron/demo/Polyhedron/resources/compatibility_shaders/shader_without_light.frag
@@ -1,4 +1,4 @@
-#version 120
+
 varying highp vec4 color;
 varying highp float dist[6];
 uniform bool is_selected;
diff --git a/Polyhedron/demo/Polyhedron/resources/heat_intensity_shader.frag b/Polyhedron/demo/Polyhedron/resources/heat_intensity_shader.frag
index 90f0bcc072b..b1b6da41e7c 100644
--- a/Polyhedron/demo/Polyhedron/resources/heat_intensity_shader.frag
+++ b/Polyhedron/demo/Polyhedron/resources/heat_intensity_shader.frag
@@ -55,8 +55,8 @@ void main(void) {
     vec3 L = light_pos.xyz - fP.xyz;
     vec3 V = -fP.xyz;
     vec3 N;
-    if(fN == highp vec3(0.0,0.0,0.0))
-      N = highp vec3(0.0,0.0,0.0);
+    if(fN == vec3(0.0,0.0,0.0))
+      N = vec3(0.0,0.0,0.0);
     else
       N = normalize(fN);
     L = normalize(L);
diff --git a/Polyhedron/demo/Polyhedron/resources/shader_flat.frag b/Polyhedron/demo/Polyhedron/resources/shader_flat.frag
index be9870bca01..f6b2484283d 100644
--- a/Polyhedron/demo/Polyhedron/resources/shader_flat.frag
+++ b/Polyhedron/demo/Polyhedron/resources/shader_flat.frag
@@ -32,8 +32,8 @@ void main(void)
   vec3 V = -fs_in.fP.xyz;
 
   vec3 N;
-  if(fs_in.normal == highp vec3(0.0,0.0,0.0))
-       N = highp vec3(0.0,0.0,0.0);
+  if(fs_in.normal == vec3(0.0,0.0,0.0))
+       N = vec3(0.0,0.0,0.0);
    else
        N = fs_in.normal;
   L = normalize(L);
diff --git a/Triangulation_3/demo/Triangulation_3/Viewer.cpp b/Triangulation_3/demo/Triangulation_3/Viewer.cpp
index ca1add3a016..6b2ae97a005 100644
--- a/Triangulation_3/demo/Triangulation_3/Viewer.cpp
+++ b/Triangulation_3/demo/Triangulation_3/Viewer.cpp
@@ -234,7 +234,7 @@ void Viewer::compile_shaders()
         "#version 120 \n"
         "varying highp vec4 fP; \n"
         "varying highp vec3 fN; \n"
-        "uniform vec4 color; \n"
+        "uniform highp vec4 color; \n"
         "uniform highp vec4 light_pos;  \n"
         "uniform highp vec4 light_diff; \n"
         "uniform highp vec4 light_spec; \n"
@@ -243,16 +243,16 @@ void Viewer::compile_shaders()
 
         "void main(void) { \n"
 
-        "   vec3 L = light_pos.xyz - fP.xyz; \n"
-        "   vec3 V = -fP.xyz; \n"
+        "   highp vec3 L = light_pos.xyz - fP.xyz; \n"
+        "   highp vec3 V = -fP.xyz; \n"
 
-        "   vec3 N = normalize(fN); \n"
+        "   highp vec3 N = normalize(fN); \n"
         "   L = normalize(L); \n"
         "   V = normalize(V); \n"
 
-        "   vec3 R = reflect(-L, N); \n"
-        "   vec4 diffuse = abs(dot(N,L)) * light_diff*color; \n"
-        "   vec4 specular = pow(max(dot(R,V), 0.0), spec_power) * light_spec; \n"
+        "   highp vec3 R = reflect(-L, N); \n"
+        "   highp vec4 diffuse = abs(dot(N,L)) * light_diff*color; \n"
+        "   highp vec4 specular = pow(max(dot(R,V), 0.0), spec_power) * light_spec; \n"
 
         "gl_FragColor = color*light_amb + diffuse + specular; \n"
         "} \n"
@@ -304,7 +304,7 @@ void Viewer::compile_shaders()
         "void main(void)\n"
         "{\n"
         "   fP = mv_matrix * vertex; \n"
-        "   vec4 TN = transfo*vec4(normal,1.0); \n"
+        "   highp vec4 TN = transfo*vec4(normal,1.0); \n"
         "   fN = mat3(mv_matrix)* TN.xyz; \n"
         "   gl_Position =  mvp_matrix * transfo* vertex; \n"
         "}"