diff --git a/src/color.rs b/src/color.rs
new file mode 100644
index 0000000..5f7a8be
--- /dev/null
+++ b/src/color.rs
@@ -0,0 +1,7 @@
+use crate::types_defined::Color;
+
+impl Color {
+    pub fn to_color(self) -> String {
+        return format!("{} {} {}\n", (self.x * 256.0) as u8, (self.y * 256.0) as u8, (self.z * 256.0) as u8);
+    }
+}
\ No newline at end of file
diff --git a/src/image.rs b/src/image.rs
index 3322262..a77b1d0 100644
--- a/src/image.rs
+++ b/src/image.rs
@@ -1,14 +1,7 @@
-use crate::{point::Point, ray::Ray, vec3::{self, Vec3}};
+use crate::hittable::Hittable;
+use crate::types_defined::{Color, Point, Ray, Sphere, Vec3};
 
 
-pub type Color = vec3::Vec3;
-
-
-impl Color {
-    pub fn to_color(self) -> String {
-        return format!("{} {} {}\n", (self.x * 256.0) as u8, (self.y * 256.0) as u8, (self.z * 256.0) as u8);
-    }
-}
 
 pub fn gen_ray_sphere_normal_ppm_p3(width: i32, height: i32, camera_center: Vec3, viewport_top_left_pixel_center: Vec3, viewport_u_delta: Vec3, viewport_v_delta: Vec3) -> String {
     let mut img_content = format!("P3\n{} {}\n255\n", width, height);
@@ -26,15 +19,15 @@ pub fn gen_ray_sphere_normal_ppm_p3(width: i32, height: i32, camera_center: Vec3
             let ray_direction = pixel_center - camera_center;
             // ray
             let r = Ray::new(camera_center,  ray_direction);
-
             /*
              球
              */
             let _sphere_center = Point::new(0.0, 0.0, -1.0);
             let sphere_radius = 0.5;
+            let sphere = Sphere::new(_sphere_center, sphere_radius);
 
             // determind color
-            let color = ray_color_at_sphere_normal(&r, _sphere_center, sphere_radius);
+            let color = ray_color(&r, sphere);
             // content
             img_content.push_str(color.to_color().as_str());
             img_content.push('\n');
@@ -44,45 +37,19 @@ pub fn gen_ray_sphere_normal_ppm_p3(width: i32, height: i32, camera_center: Vec3
     img_content
 }
 
-fn hit_sphere_normal(r: &Ray, sphere_center: Point, sphere_radius: f32) -> f32 {
-    let a: f32 = r.direction.length_squared();
-    let h = r.direction.dot(sphere_center - r.point);
-    // let b = -2.0 * r.direction.dot(sphere_center - r.point);
-    let c = (sphere_center - r.point).length_squared() - sphere_radius * sphere_radius;
-
-    let discriminant = h*h - a*c;
-
-    // // 两个焦点
-    let disc_sqrt = discriminant.sqrt();
-    let near = (h - disc_sqrt) / a;
-    let far = (h + disc_sqrt) / a;
-
-    // 射线起点可能在球内的情况
-    if near >= 0.0 && far >= 0.0 {
-        return near.min(far);
-    } else if near > 0.0 {
-        return near;
-    } else if far > 0.0 {
-        return far;
-    } else {
-        return -1.0
-    }
-}
-
 /*
 ray color functions
 */
-fn ray_color_at_sphere_normal(r: &Ray, sphere_center: Point, sphere_radius: f32) -> Color {
-
-    let t = hit_sphere_normal(r, sphere_center, sphere_radius);
-    if t >= 0.0 {
-        let inter_point = r.at(t);
+fn ray_color<H: Hittable>(r: &Ray, h: H) -> Color {
+    let hr = h.hit(&r, 0.0, f32::MAX);
+    if hr.t >= 0.0 {
+        let inter_point = hr.p;
         // 单位向量
         let n = inter_point / inter_point.dot(inter_point);
         // 法向量也是 -1～1  +1再x0.5让他落到颜色的区间
-        return 0.5 * (n - sphere_center + Point::new(1.0, 1.0, 1.0))
+        // return 0.5 * (n - sphere_center + Point::new(1.0, 1.0, 1.0))
+        return 0.5 * (hr.normal + Point::new(1.0, 1.0, 1.0))
     }
-
     // v / |v|
     let unit_direction = r.direction / r.direction.length();
     let a = 0.5*(unit_direction.y + 1.0);
diff --git a/src/main.rs b/src/main.rs
index 3a80d9c..e0d84b6 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,14 +1,15 @@
 use write_file_util::{write_image};
-use vec3::{Vec3};
-use point::{Point};
 
 use crate::image::{gen_ray_sphere_normal_ppm_p3};
-
+use crate::types_defined::{Point, Vec3};
 mod image;
 mod write_file_util;
 mod vec3;
-mod point;
 mod ray;
+mod hittable;
+mod sphere;
+mod types_defined;
+mod color;
 
 fn main() {
     ray_sphere_normal_scene_render();
diff --git a/src/point.rs b/src/point.rs
deleted file mode 100644
index c3e4956..0000000
--- a/src/point.rs
+++ /dev/null
@@ -1,4 +0,0 @@
-use crate::vec3;
-
-pub type Point = vec3::Vec3;
-
diff --git a/src/ray.rs b/src/ray.rs
index 17d04a8..e140f51 100644
--- a/src/ray.rs
+++ b/src/ray.rs
@@ -1,17 +1,6 @@
 use std::fmt;
 use std::fmt::{Display};
-
-use crate::{point::Point, vec3::Vec3};
-
-
-/*
-fn: P(t) = t*b
-*/
-#[derive(Debug)]
-pub struct Ray {
-    pub point: Point,
-    pub direction: Vec3
-}
+use crate::types_defined::{Point, Ray, Vec3};
 
 impl Ray {
     pub fn new(p: Point, direction: Vec3) -> Ray {
diff --git a/src/types_defined.rs b/src/types_defined.rs
new file mode 100644
index 0000000..5557cc7
--- /dev/null
+++ b/src/types_defined.rs
@@ -0,0 +1,37 @@
+/*
+* [3]
+*/
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct Vec3 {
+    pub x: f32,
+    pub y: f32,
+    pub z: f32,
+}
+pub type Point = Vec3;
+pub type Color = Vec3;
+
+/*
+fn: P(t) = t*b
+*/
+#[derive(Debug)]
+pub struct Ray {
+    pub point: Point,
+    pub direction: Vec3
+}
+
+pub struct HitRecord {
+    pub t: f32,
+    pub p: Vec3,
+    pub normal: Vec3,
+}
+
+
+/*
+/////////////
+// for test
+/////////////
+*/
+pub struct Sphere {
+    pub center: Point,
+    pub radius: f32,
+}
\ No newline at end of file
diff --git a/src/vec3.rs b/src/vec3.rs
index 6b2ba95..cc277df 100644
--- a/src/vec3.rs
+++ b/src/vec3.rs
@@ -1,15 +1,7 @@
 
 use std::{fmt::Display, ops::{Add, AddAssign, Div, Mul, MulAssign, Sub}};
 use std::fmt;
-/*
-* [3]
-*/
-#[derive(Debug, Clone, Copy, PartialEq)]
-pub struct Vec3 {
-    pub x: f32,
-    pub y: f32,
-    pub z: f32,
-}
+use crate::types_defined::Vec3;
 
 impl Display for Vec3 {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {