diff --git a/src/main.rs b/src/main.rs
index 2ec00a3..1f3966c 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -22,11 +22,11 @@ fn main() {
 
 fn camera_render() {
 
-    let scale = 2;
+    let scale = 1;
     let width: i32 = 800/scale;
     let height: i32 = 600/scale;
-    let sample_times = 50;
-    let reflect_depth = 100;
+    let sample_times = 127;
+    let reflect_depth = 127;
 
 
     let pw_r = PPMWriter::new(
@@ -59,10 +59,13 @@ fn camera_render() {
     let left_m = Some(MaterialKind::Metal(Metal{albedo: Color::new(0.799, 0.599, 0.799), fuzz: 0.0005}));
     let left_behind_m = Some(MaterialKind::Lambertian(Lambertian{albedo: Color::new(0.799, 0.599, 0.599)}));
     let right_m = Some(MaterialKind::Metal(Metal{albedo: Color::new(0.8, 0.6, 0.2), fuzz: 0.003}));
-    let left_dia_m = Some(MaterialKind::Dielectric(Dielectric{albedo: Color::new(0.8, 0.6, 0.2), refraction_index: 1.5}));
+    // 折射率 1.33
+    let left_dia_m = Some(MaterialKind::Dielectric(Dielectric{albedo: Color::new(0.8, 0.6, 0.2), refraction_index: 1.00 / 1.33}));
+    let left_dia_small_m = Some(MaterialKind::Dielectric(Dielectric{albedo: Color::new(0.8, 0.6, 0.2), refraction_index: 1.00 / 2.5}));
 
-    // world.put(Box::new(Sphere::new(Point::new(0.0,    0.0, -1.0), 0.5, center_m)));
+    world.put(Box::new(Sphere::new(Point::new(0.0,    0.0, -1.0), 0.5, center_m)));
     world.put(Box::new(Sphere::new(Point::new(-1.0,    0.0, -1.0), 0.5, left_dia_m)));
+    world.put(Box::new(Sphere::new(Point::new(-1.0,    0.0, -1.0), 0.2, left_dia_small_m)));
     // world.put(Box::new(Sphere::new(Point::new(-1.0,    0.0, -1.0), 0.5, left_m)));
     world.put(Box::new(Sphere::new(Point::new(-3.5,    1.5, -5.5), 1.5, left_behind_m)));
     world.put(Box::new(Sphere::new(Point::new(1.0,    0.0, -1.0), 0.5, right_m)));
diff --git a/src/material.rs b/src/material.rs
index 69e1358..a2d7b40 100644
--- a/src/material.rs
+++ b/src/material.rs
@@ -86,14 +86,6 @@ pub struct Dielectric {
 impl Material for Dielectric {
     fn scatter(&self, r_in: &Ray, hit_record: &mut HitRecord, attenuation: &mut Color, scattered: &mut Ray) -> bool {
 
-        // attenuation = color(1.0, 1.0, 1.0);
-        // double ri = rec.front_face ? (1.0/refraction_index) : refraction_index;
-
-        // vec3 unit_direction = unit_vector(r_in.direction());
-        // vec3 refracted = refract(unit_direction, rec.normal, ri);
-
-        // scattered = ray(rec.p, refracted);
-        // return true;
         *attenuation = Color::new(1.0, 1.0, 1.0);
         let ri = if hit_record.front_face {
             1.0 / self.refraction_index
@@ -102,27 +94,21 @@ impl Material for Dielectric {
         };
 
         let unit_direction = r_in.direction.normalize();
-        let refracted  = refract(unit_direction, hit_record.normal, ri);
-        *scattered = Ray::new(hit_record.p, refracted);
+
+
+        let cos = -unit_direction.dot(hit_record.normal).min(1.0);
+        let sin = (1.0 - cos.powi(2)).sqrt();
+
+        let direction = if self.refraction_index * sin > 1.0 {
+            reflect(unit_direction, hit_record.normal)
+        } else {
+            refract(unit_direction, hit_record.normal, self.refraction_index)
+        };
+
+
+        // let refracted  = refract(unit_direction, hit_record.normal, ri);
+        *scattered = Ray::new(hit_record.p, direction);
 
         true
-
-
-
-
-
-
-
-        // *attenuation = Color::new(1.0, 1.0, 1.0);
-        // let ri = if hit_record.front_face {
-        //     1.0/self.refraction_index
-        // } else {
-        //     self.refraction_index
-        // };
-
-        // let normalized = r_in.direction;
-        // let refracted = refract(normalized, hit_record.normal, ri);
-        // *scattered = Ray::new(hit_record.p, refracted);
-        // true
     }
 }
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