diff --git a/src/main.rs b/src/main.rs
index dcb6806..145ff5a 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -113,14 +113,14 @@ fn main() -> io::Result<()> {
 			let img_coords: Vec2 = vec2(x as f32, y as f32);
 
 			// perspective projection
-			let off = (img_coords - img_size * 0.5) / (img_size.y * 0.5);
-			let base = vec3(0.0, 0.0, -10.0);
+			let off = (img_coords - img_size * 0.5) / img_size.y;
+			let base = vec3(0.0, 0.0, -20.0);
 			let ray = vec3(off.x, off.y, 1.0);
 
 			// orthographic projection
-			let off = (img_coords - img_size * 0.5) / SCALE;
-			let base = vec3(off.x, off.y, -10.0);
-			let ray = vec3(0.0, 0.0, 1.0);
+			// let off = (img_coords - img_size * 0.5) / SCALE;
+			// let base = vec3(off.x, off.y, -10.0);
+			// let ray = vec3(0.0, 0.0, 1.0);
 
 			let base = m_camera * base;
 			let ray = m_camera * normalize(ray);
@@ -138,11 +138,10 @@ fn main() -> io::Result<()> {
 	let mut f = BufWriter::new(f);
 	write!(f, "P6\n")?;
 	write!(f, "{W} {H} 255\n")?;
-	f.write(img.data());
+	f.write(img.data())?;
 	Ok(())
 }
 
 fn edge_dist(a: Vec3, b: Vec3, base: Vec3, dir: Vec3) -> f32 {
-	let edge = normalize(b - a);
-	dot(edge, cross(base - a, base + dir - a))
+	Mat3 { c0: b - a, c1: base - a, c2: dir }.determinant()
 }