Put zone texture to environment texture unit on OpenGL ES. Fix web build including texture unit mappings which are not included in the shaders.

Source/Urho3D/Graphics/Batch.cpp

@@ -580,6 +580,16 @@ void Batch::Prepare(View* view, Camera* camera, bool setModelTransform, bool all
         }
     }
 
+    // Set zone texture if necessary
+#ifndef GL_ES_VERSION_2_0
+    if (zone_ && graphics->HasTextureUnit(TU_ZONE))
+        graphics->SetTexture(TU_ZONE, zone_->GetZoneTexture());
+#else
+    // On OpenGL ES set the zone texture to the environment unit instead
+    if (zone_ && zone_->GetZoneTexture() && graphics->HasTextureUnit(TU_ENVIRONMENT))
+        graphics->SetTexture(TU_ENVIRONMENT, zone_->GetZoneTexture());
+#endif
+
     // Set material-specific shader parameters and textures
     if (material_)
     {
@@ -618,12 +628,6 @@ void Batch::Prepare(View* view, Camera* camera, bool setModelTransform, bool all
             graphics->SetTexture(TU_LIGHTSHAPE, shapeTexture);
         }
     }
-
-    // Set zone texture if necessary
-#ifdef DESKTOP_GRAPHICS
-    if (zone_ && graphics->HasTextureUnit(TU_ZONE))
-        graphics->SetTexture(TU_ZONE, zone_->GetZoneTexture());
-#endif
 }
 
 void Batch::Draw(View* view, Camera* camera, bool allowDepthWrite) const

Source/Urho3D/Graphics/OpenGL/OGLGraphics.cpp

@@ -3074,7 +3074,7 @@ void Graphics::SetTextureUnitMappings()
     textureUnits_["LightSpotMap"] = TU_LIGHTSHAPE;
     textureUnits_["LightCubeMap"] = TU_LIGHTSHAPE;
     textureUnits_["ShadowMap"] = TU_SHADOWMAP;
-#ifdef DESKTOP_GRAPHICS
+#ifndef GL_ES_VERSION_2_0
     textureUnits_["VolumeMap"] = TU_VOLUMEMAP;
     textureUnits_["FaceSelectCubeMap"] = TU_FACESELECT;
     textureUnits_["IndirectionCubeMap"] = TU_INDIRECTION;