diff --git a/src/example.rs b/src/example.rs
index a11f5d48..c4cb1020 100644
--- a/src/example.rs
+++ b/src/example.rs
@@ -4,7 +4,7 @@ pub const MUNICH_X: u32 = 17425;
 pub const MUNICH_Y: u32 = 11365;
 pub const MUNICH_Z: u8 = 15;
 
-pub fn fetch_munich_tiles(worker_loop: &WorkerLoop) {
+pub fn fetch_munich_tiles(worker_loop: &mut WorkerLoop) {
     // This size matches the amount of tiles which are loaded on zoom 15 on FHD
     for x in 0..8 {
         for y in 0..5 {
diff --git a/src/io/worker_loop.rs b/src/io/worker_loop.rs
index 8ce2f475..f5cfb4a1 100644
--- a/src/io/worker_loop.rs
+++ b/src/io/worker_loop.rs
@@ -1,4 +1,4 @@
-use std::collections::VecDeque;
+use std::collections::{HashSet, VecDeque};
 
 use std::sync::{Arc, Condvar, Mutex};
 
@@ -22,6 +22,7 @@ pub struct TesselatedLayer {
 
 #[derive(Clone)]
 pub struct WorkerLoop {
+    loaded_coords: Arc<Mutex<HashSet<TileCoords>>>,
     requests: Arc<WorkQueue<TileCoords>>,
     responses: Arc<WorkQueue<TesselatedLayer>>,
 }
@@ -35,14 +36,28 @@ impl Drop for WorkerLoop {
 impl WorkerLoop {
     pub fn new() -> Self {
         Self {
+            loaded_coords: Arc::new(Mutex::new(HashSet::new())),
             requests: Arc::new(WorkQueue::new()),
             responses: Arc::new(WorkQueue::new()),
         }
     }
 
-    pub fn fetch(&self, coords: TileCoords) {
-        info!("new tile request: {:?}", &coords);
-        self.requests.push(coords);
+    pub fn is_loaded(&self, coords: &TileCoords) -> bool {
+        if let Ok(loaded_coords) = self.loaded_coords.lock() {
+            loaded_coords.contains(coords)
+        } else {
+            false
+        }
+    }
+    pub fn fetch(&mut self, coords: TileCoords) {
+        if let Ok(mut loaded_coords) = self.loaded_coords.lock() {
+            if loaded_coords.contains(&coords) {
+                return;
+            }
+            loaded_coords.insert(coords);
+            info!("new tile request: {:?}", &coords);
+            self.requests.push(coords);
+        }
     }
 
     pub fn pop_all(&self) -> Vec<TesselatedLayer> {
diff --git a/src/main_loop.rs b/src/main_loop.rs
index 1b09d1f2..9a5645f2 100644
--- a/src/main_loop.rs
+++ b/src/main_loop.rs
@@ -11,12 +11,12 @@ use crate::render::render_state::RenderState;
 pub async fn setup(
     window: winit::window::Window,
     event_loop: EventLoop<()>,
-    worker_loop: Box<WorkerLoop>,
+    mut worker_loop: Box<WorkerLoop>,
 ) {
     info!("== mapr ==");
 
-    fetch_munich_tiles(worker_loop.as_ref());
-
+    /*    fetch_munich_tiles(worker_loop.as_ref());
+     */
     let mut input = InputController::new(0.2, 100.0);
     let mut maybe_state: Option<RenderState> = if cfg!(target_os = "android") {
         None
@@ -84,7 +84,7 @@ pub async fn setup(
                     let dt = now - last_render_time;
                     last_render_time = now;
                     input.update_state(state, dt);
-                    state.upload_tile_geometry(&worker_loop);
+                    state.upload_tile_geometry(&mut worker_loop);
                     match state.render() {
                         Ok(_) => {}
                         Err(wgpu::SurfaceError::Lost) => {
diff --git a/src/render/render_state.rs b/src/render/render_state.rs
index 36b43d79..92322f49 100644
--- a/src/render/render_state.rs
+++ b/src/render/render_state.rs
@@ -1,6 +1,8 @@
+use cgmath::{Point3, Vector3};
 use std::default::Default;
 use std::{cmp, iter};
 
+use crate::coords::{TileCoords, WorldCoords, WorldTileCoords};
 use wgpu::{Buffer, Limits, Queue};
 use winit::dpi::PhysicalSize;
 use winit::window::Window;
@@ -347,9 +349,27 @@ impl RenderState {
 
     // TODO: Could we draw inspiration from StagingBelt (https://docs.rs/wgpu/latest/wgpu/util/struct.StagingBelt.html)?
     // TODO: What is StagingBelt for?
-    pub fn upload_tile_geometry(&mut self, worker_loop: &WorkerLoop) {
-        println!("1: {:?}", self.camera.view_bounding_box(&self.perspective));
-        println!("2: {:?}", self.camera.view_bounding_box2(&self.perspective));
+    pub fn upload_tile_geometry(&mut self, worker_loop: &mut WorkerLoop) {
+        if let Some(view_box) = self.camera.view_bounding_box(&self.perspective) {
+            /*let view_box = self.camera.view_bounding_box2(&self.perspective).unwrap();*/
+
+            let min_world: WorldCoords = Point3::new(view_box.min.x, view_box.min.y, 15.0).into();
+            let min_world_tile: WorldTileCoords = min_world.into();
+            let min_tile: TileCoords = min_world_tile.into();
+            let max_world: WorldCoords = Point3::new(view_box.max.x, view_box.max.y, 15.0).into();
+            let max_world_tile: WorldTileCoords = max_world.into();
+            let max_tile: TileCoords = max_world_tile.into();
+
+            for x in min_tile.x..max_tile.x + 1 {
+                for y in min_tile.y..max_tile.y + 1 {
+                    let to_be_fetched = (x, y, 15).into();
+                    if !worker_loop.is_loaded(&to_be_fetched) {
+                        // FIXME: is_loaded is not correct right now
+                        worker_loop.fetch(to_be_fetched);
+                    }
+                }
+            }
+        }
 
         let upload = worker_loop.pop_all();
 
@@ -468,9 +488,18 @@ impl RenderState {
             {
                 // Draw masks
                 pass.set_pipeline(&self.mask_pipeline);
-                pass.set_vertex_buffer(0, self.tile_mask_instances_buffer.slice(..));
-                // Draw 7 squares each out of 6 vertices
-                pass.draw(0..6, 0..self.tile_mask_pattern.instances());
+                let masks = self.tile_mask_pattern.as_slice();
+                if !masks.is_empty() {
+                    pass.set_vertex_buffer(
+                        0,
+                        self.tile_mask_instances_buffer.slice(
+                            0..masks.len() as u64
+                                * std::mem::size_of::<ShaderTileMaskInstance>() as u64,
+                        ),
+                    );
+                    // Draw 7 squares each out of 6 vertices
+                    pass.draw(0..6, 0..self.tile_mask_pattern.instances());
+                }
             }
             {
                 for entry in self.buffer_pool.available_vertices() {