diff --git a/shaders/lighting.glsl b/shaders/lighting.glsl
new file mode 100644
index 0000000..22ad009
--- /dev/null
+++ b/shaders/lighting.glsl
@@ -0,0 +1,16 @@
+uniform sampler2D texture;
+uniform float ambient;
+uniform bool has_texture;
+
+void main()
+{
+    // lookup the pixel in the texture
+    vec4 pixel = texture2D(texture, gl_TexCoord[0].xy);
+
+    // multiply it by the color
+    vec4 col = gl_Color;
+    if (has_texture) {
+        col = gl_Color * pixel;
+    }
+    gl_FragColor = vec4(col.x * ambient, col.y * ambient, col.z * ambient, col.w);
+}
\ No newline at end of file
diff --git a/src/app.rs b/src/app.rs
index 7602a72..3af3b5a 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -220,8 +220,9 @@ impl App {
 
     fn do_rendering(&mut self) {
         self.rw.clear(Color::rgb(55, 221, 231));
-        self.game.draw_world(&mut self.rw, &self.res);
-        self.game.draw_entities(&mut self.rw);
+        self.game.render_pre_step(&mut self.res);
+        self.game.draw_world(&mut self.rw, &mut self.res);
+        self.game.draw_entities(&mut self.rw, &mut self.res);
         self.sf_egui
             .do_frame(|ctx| {
                 if self.debug.panel {
@@ -290,6 +291,8 @@ fn debug_panel_ui(
         ui.add(egui::DragValue::new(&mut vol));
         res.surf_music.set_volume(vol);
         ui.separator();
+        ui.label("Ambient light");
+        ui.add(egui::DragValue::new(&mut game.ambient_light).speed(0.01));
         egui::ScrollArea::vertical().show(ui, |ui| {
             gamedebug_core::for_each_imm(|info| match info {
                 gamedebug_core::Info::Msg(msg) => {
diff --git a/src/game.rs b/src/game.rs
index f11ec22..5d8f434 100644
--- a/src/game.rs
+++ b/src/game.rs
@@ -1,7 +1,8 @@
 mod player;
 
 use sfml::graphics::{
-    Color, Rect, RectangleShape, RenderTarget, RenderWindow, Shape, Sprite, Transformable,
+    Color, Rect, RectangleShape, RenderStates, RenderTarget, RenderWindow, Shape, Sprite,
+    Transformable,
 };
 
 use crate::{
@@ -23,6 +24,7 @@ pub struct GameState {
     pub current_biome: Biome,
     pub prev_biome: Biome,
     pub worldgen: Worldgen,
+    pub ambient_light: f32,
 }
 
 #[derive(PartialEq, Eq, Clone, Copy)]
@@ -32,41 +34,51 @@ pub enum Biome {
 }
 
 impl GameState {
-    pub(crate) fn draw_world(&mut self, rw: &mut RenderWindow, res: &Res) {
+    pub(crate) fn draw_world(&mut self, rw: &mut RenderWindow, res: &mut Res) {
+        let mut rs = RenderStates::default();
+        res.lighting_shader.set_uniform_bool("has_texture", true);
+        rs.set_shader(Some(&res.lighting_shader));
         let mut s = Sprite::with_texture(&res.tile_atlas);
         for_each_tile_on_screen(self.camera_offset, |tp, sp| {
             let tile = self.world.tile_at_mut(tp, &self.worldgen);
             s.set_position(sp.to_sf_vec());
             if tile.bg != Tile::EMPTY {
                 s.set_texture_rect(Rect::new((tile.bg - 1) as i32 * 32, 0, 32, 32));
-                rw.draw(&s);
+                rw.draw_with_renderstates(&s, &rs);
             }
             if tile.mid != Tile::EMPTY {
                 s.set_texture_rect(Rect::new((tile.mid - 1) as i32 * 32, 0, 32, 32));
-                rw.draw(&s);
+                rw.draw_with_renderstates(&s, &rs);
             }
             if tile.fg != Tile::EMPTY {
                 s.set_texture_rect(Rect::new((tile.fg - 1) as i32 * 32, 0, 32, 32));
-                rw.draw(&s);
+                rw.draw_with_renderstates(&s, &rs);
             }
         });
     }
-    pub fn draw_entities(&mut self, rw: &mut RenderWindow) {
+    pub fn draw_entities(&mut self, rw: &mut RenderWindow, res: &mut Res) {
+        let mut rend_st = RenderStates::default();
+        res.lighting_shader.set_uniform_bool("has_texture", false);
+        rend_st.set_shader(Some(&res.lighting_shader));
         let (x, y, w, h) = self.player.col_en.en.xywh();
-        let mut rs = RectangleShape::new();
-        rs.set_position((
+        let mut rect_sh = RectangleShape::new();
+        rect_sh.set_position((
             (x - self.camera_offset.x as i32) as f32,
             (y - self.camera_offset.y as i32) as f32,
         ));
-        rs.set_size((w as f32, h as f32));
-        rw.draw(&rs);
-        rs.set_size((2., 2.));
-        rs.set_fill_color(Color::RED);
-        rs.set_position((
+        rect_sh.set_size((w as f32, h as f32));
+        rw.draw_with_renderstates(&rect_sh, &rend_st);
+        rect_sh.set_size((2., 2.));
+        rect_sh.set_fill_color(Color::RED);
+        rect_sh.set_position((
             (self.player.col_en.en.pos.x - self.camera_offset.x as i32) as f32,
             (self.player.col_en.en.pos.y - self.camera_offset.y as i32) as f32,
         ));
-        rw.draw(&rs);
+        rw.draw(&rect_sh);
+    }
+    pub fn render_pre_step(&mut self, res: &mut Res) {
+        res.lighting_shader
+            .set_uniform_float("ambient", self.ambient_light);
     }
 }
 
@@ -100,6 +112,7 @@ impl Default for GameState {
             current_biome: Biome::Surface,
             prev_biome: Biome::Surface,
             worldgen: Worldgen::default(),
+            ambient_light: 1.0,
         }
     }
 }
diff --git a/src/res.rs b/src/res.rs
index 1a9f95c..5e71c52 100644
--- a/src/res.rs
+++ b/src/res.rs
@@ -1,9 +1,14 @@
-use sfml::{audio::Music, graphics::Texture, SfBox};
+use sfml::{
+    audio::Music,
+    graphics::{Shader, ShaderType, Texture},
+    SfBox,
+};
 
 pub struct Res {
     pub tile_atlas: SfBox<Texture>,
     pub surf_music: Music<'static>,
     pub und_music: Music<'static>,
+    pub lighting_shader: Shader<'static>,
 }
 
 impl Res {
@@ -12,6 +17,10 @@ impl Res {
             tile_atlas: Texture::from_file("res/tiles.png")?,
             surf_music: Music::from_file("res/music.ogg").unwrap(),
             und_music: Music::from_file("res/cave2.ogg").unwrap(),
+            lighting_shader: Shader::from_memory(
+                include_str!("../shaders/lighting.glsl"),
+                ShaderType::Fragment,
+            )?,
         })
     }
 }