diff --git a/src/bin/minitracer/anim.rs b/src/bin/minitracer/anim.rs
index 56dbd58..33e7205 100644
--- a/src/bin/minitracer/anim.rs
+++ b/src/bin/minitracer/anim.rs
@@ -5,6 +5,7 @@ pub struct SphereParams {
 	pub radius: f32,
 	pub color: Vec3,
 	pub alpha: f32,
+	pub glossiness: f32,
 	pub origin: Vec3,
 	pub amplitudes: Vec3,
 	pub frequencies: Vec3,
@@ -19,6 +20,7 @@ pub struct SphereParamsDistribution {
 	pub dampl: Uniform<f32>,
 	pub dfreq: Uniform<f32>,
 	pub dphase: Uniform<f32>,
+	pub dgloss: Uniform<f32>,
 }
 
 impl Default for SphereParamsDistribution {
@@ -31,6 +33,7 @@ impl Default for SphereParamsDistribution {
 			dampl: Uniform::new(0.3, 0.8),
 			dfreq: Uniform::new(0.2, 1.5),
 			dphase: Uniform::new(0., 2. * std::f32::consts::PI),
+			dgloss: Uniform::new(0., 1.),
 		}
 	}
 }
@@ -42,6 +45,7 @@ impl SphereParamsDistribution {
 			radius: self.drad.sample(rgen),
 			color: self.dcol.sample3(rgen).normalize(),
 			alpha: self.demit.sample(rgen),
+			glossiness: self.dgloss.sample(rgen),
 			amplitudes: self.dampl.sample3(rgen),
 			frequencies: self.dfreq.sample3(rgen),
 			phases: self.dphase.sample3(rgen),
@@ -54,12 +58,14 @@ impl SphereParams {
 		let center = self.origin + self.amplitudes * (self.frequencies * time + self.phases).map(|x| x.sin());
 		let radius = self.radius;
 		let emit_color = self.alpha * self.color;
+		let glossiness = self.glossiness;
 		let reflect_color = 0.6 * self.color + Vec3::splat(0.2);
 		crate::Sphere {
 			center,
 			radius,
 			emit_color,
 			reflect_color,
+			glossiness,
 		}
 	}
 }
diff --git a/src/bin/minitracer/trace.rs b/src/bin/minitracer/trace.rs
index be57f88..177436a 100644
--- a/src/bin/minitracer/trace.rs
+++ b/src/bin/minitracer/trace.rs
@@ -13,12 +13,12 @@ pub struct Params {
 }
 
 #[derive(Debug, Clone, Copy)]
-#[repr(C)]
 pub struct Sphere {
 	pub center: Vec3,
 	pub radius: f32,
 	pub emit_color: Vec3,
 	pub reflect_color: Vec3,
+	pub glossiness: f32,
 }
 
 #[derive(Debug, Clone, Copy, Pod, Zeroable)]
@@ -37,7 +37,7 @@ struct SphereData {
 	emit_color: Vec3,
 	pad1: f32,
 	reflect_color: Vec3,
-	pad2: f32,
+	glossiness: f32,
 }
 
 pub struct Tracer {
@@ -155,7 +155,7 @@ impl TracerData {
 				emit_color: s.emit_color,
 				pad1: 0.0,
 				reflect_color: s.reflect_color,
-				pad2: 0.0,
+				glossiness: s.glossiness,
 			})
 			.collect();
 		let spheres_buf = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
diff --git a/src/bin/minitracer/trace.wgsl b/src/bin/minitracer/trace.wgsl
index 1e4d264..1275f3e 100644
--- a/src/bin/minitracer/trace.wgsl
+++ b/src/bin/minitracer/trace.wgsl
@@ -9,6 +9,7 @@ struct Sphere {
 	radius: f32,
 	emit_color: vec3f,
 	reflect_color: vec3f,
+	glossiness: f32,
 }
 
 struct Vertex {
@@ -87,7 +88,7 @@ fn trace_fragment(in: Varying) -> vec4f {
 		color *= s.reflect_color;
 		let diffuse = normal + rand_sphere();
 		let specular = reflect(ray, normal);
-		ray = normalize(mix(diffuse, specular, 0.8));
+		ray = normalize(mix(diffuse, specular, s.glossiness));
 		if (length(color) < params.min_strength) {
 			break;
 		}