6.3.An Abstraction for Hittable Objects

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);
+    }
+}

src/hittable.rs

@@ -0,0 +1,5 @@
+use crate::types_defined::{HitRecord, Ray};
+
+pub trait Hittable {
+    fn hit(self, r: &Ray, t_min: f32, t_max: f32) -> HitRecord;
+}

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');
@@ -44,184 +37,21 @@ pub fn gen_ray_sphere_normal_ppm_p3(width: i32, height: i32, camera_center: Vec3
     img_content
 }
 
-
-pub fn gen_ray_sphere_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);
-
-    for j in 0..height {
-       
-        if j % 10 == 0 {
-            println!("scan line {}/{} ", j + 1, height);
-        }
-
-        for i in 0..width {
-            // every pixcel's position
-            let pixel_center = viewport_top_left_pixel_center + (i as f32 * viewport_u_delta) + (j as f32 * viewport_v_delta);
-            // Vector(camera, pixcel)
-            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;
-
-            // determind color
-            let color = ray_color_at_sphere(&r, _sphere_center, sphere_radius);
-            // content
-            img_content.push_str(color.to_color().as_str());
-            img_content.push('\n');
-        }
-    }
-
-    img_content
-}
-
-
-pub fn gen_ray_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);
-
-    for j in 0..height {
-       
-        if j % 10 == 0 {
-            println!("scan line {}/{} ", j + 1, height);
-        }
-
-        for i in 0..width {
-            // every pixcel's position
-            let pixel_center = viewport_top_left_pixel_center + (i as f32 * viewport_u_delta) + (j as f32 * viewport_v_delta);
-            // Vector(camera, pixcel)
-            let ray_direction = pixel_center - camera_center;
-            // ray
-            let r = Ray::new(camera_center,  ray_direction);
-            // determind color
-            let color = ray_color(&r);
-            // content
-            img_content.push_str(color.to_color().as_str());
-            img_content.push('\n');
-        }
-    }
-
-    img_content
-}
-
-
-/*
-b^ - 4ac > 0 : 2 交点； = 0：1交点；< 0 : 无交点
-*/
-fn hit_sphere(r: &Ray, sphere_center: Point, sphere_radius: f32) -> bool {
-    let a = r.direction.dot(r.direction);
-    let b_sqrt = (-2.0 * (r.direction.dot(sphere_center - r.point))).powi(2);
-    let c = (sphere_center - r.point).dot(sphere_center - r.point) - sphere_radius.powi(2);
-
-    return b_sqrt - 4.0 * a * c >= 0.0;
-}
-
-
-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);
     return (1.0-a)*Color::new(1.0, 1.0, 1.0) + a*Color::new(0.5, 0.7, 1.0);
-}
-
-fn ray_color_at_sphere(r: &Ray, sphere_center: Point, sphere_radius: f32) -> Color {
-
-    // return RED if hit sphere
-    if hit_sphere(r, sphere_center, sphere_radius) {
-        return Color::new(0.4, 0.4, 0.2);
-    }
-
-    // v / |v|
-    let unit_direction = r.direction / r.direction.length();
-    let a = 0.5*(unit_direction.y + 1.0);
-    return (1.0-a)*Color::new(1.0, 1.0, 1.0) + a*Color::new(0.5, 0.7, 1.0);
-}
-
-fn ray_color(r: &Ray) -> Color {
-    // v / |v|
-    let unit_direction = r.direction / r.direction.length();
-    let a = 0.5*(unit_direction.y + 1.0);
-    return (1.0-a)*Color::new(1.0, 1.0, 1.0) + a*Color::new(0.5, 0.7, 1.0);
-}
-
-
-/*
-* -------width(i)-------
-* |
-* |
-* height(j)
-* |
-* |
-* ----------------------
-* 
-* ppm p3 format:
-* 
-* P3
-* 
-* [width] [height]
-* [max color]
-* R1 G1 B1
-* R2 G2 B2
-* R3 G3 B3
-* ...xN
-*/
-pub fn gen_gradient_ppm_p3(width: i32, height: i32) -> String {
-    let mut img_content = format!("P3\n{} {}\n255\n", width, height);
-
-    for j in 0..height {
-        println!("scan line {}/{} ", j + 1, height);
-        for i in 0..width {
-            let r = i as f32 / (width-1) as f32;
-            let g = j as f32 / (height-1) as f32;
-            let b = (i+j) as f32 / (width + height - 2) as f32;
-
-            let color = Color::new(r, g, b);
-            img_content.push_str(color.to_color().as_str());
-
-            img_content.push('\n');
-        }
-    }
-
-    img_content
 }

src/main.rs

@@ -1,26 +1,18 @@
 use write_file_util::{write_image};
-use image::{gen_gradient_ppm_p3, gen_ray_ppm_p3, Color};
-use vec3::{Vec3};
-use point::{Point};
-use ray::{Ray};
-
-use crate::image::{gen_ray_sphere_normal_ppm_p3, gen_ray_sphere_ppm_p3};
 
+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() {
-    gen_gradient_ppm();
-    println!("==================================");
-    ray_scene_render();
-    println!("==================================");
-    ray_sphere_scene_render();
-    println!("==================================");
     ray_sphere_normal_scene_render();
-    println!("==================================");
 }
 
 
@@ -58,96 +50,4 @@ fn ray_sphere_normal_scene_render() {
     let ppm_content = gen_ray_sphere_normal_ppm_p3(image_width, image_height, camera_center, viewport_top_left_pixel_center, viewport_u_delta, viewport_v_delta);
 
     write_image(ppm_content, "./target/ray_sphere_normal_scene_render.ppm".to_string())
-}
-
-fn ray_sphere_scene_render() {
-    let aspect_ratio = 16.0/9.0;
-    let image_width = 400;
-    // aleast 1px
-    let image_height = ((image_width as f32 / aspect_ratio) as i32).max(1);
-
-    let viewport_height = 2.0;
-    let viewport_width = viewport_height * (image_width as f32 / image_height as f32);
-
-    println!("set image({},{}), viewport({},{})", image_width, image_height, viewport_width, viewport_height);
-    let viewport_u = Vec3::new(viewport_width, 0.0, 0.0);
-    // image x--> right
-    //       |
-    //       y
-    // space: y up , x right , z back, -z front
-    let viewport_v = Vec3::new(0.0, -viewport_height, 0.0);
-
-    // width per pix
-    let viewport_u_delta = viewport_u / (image_width as f32);
-    // height per pix
-    let viewport_v_delta = viewport_v / (image_height as f32);
-
-    // camerea position
-    let camera_center = Point::new(0.0, 0.0, 0.0);
-    // -z  1.0  viewport to camera
-    let focal_length = Vec3::new(0.0, 0.0, -1.0);
-    // camera position --> viewport center ---> top center --> top left
-    let viewport_top_left_pixel = camera_center + focal_length - viewport_u / 2.0 - viewport_v / 2.0;
-    // padding 0.5* delta u/v
-    let viewport_top_left_pixel_center = viewport_top_left_pixel - viewport_u_delta / 2.0 - viewport_v_delta / 2.0;
-
-    let ppm_content = gen_ray_sphere_ppm_p3(image_width, image_height, camera_center, viewport_top_left_pixel_center, viewport_u_delta, viewport_v_delta);
-
-    write_image(ppm_content, "./target/ray_sphere_scene_render.ppm".to_string())
-}
-
-
-fn ray_scene_render() {
-    let aspect_ratio = 16.0/9.0;
-    let image_width = 400;
-    // aleast 1px
-    let image_height = ((image_width as f32 / aspect_ratio) as i32).max(1);
-
-    let viewport_height = 2.0;
-    let viewport_width = viewport_height * (image_width as f32 / image_height as f32);
-
-    println!("set image({},{}), viewport({},{})", image_width, image_height, viewport_width, viewport_height);
-    let viewport_u = Vec3::new(viewport_width, 0.0, 0.0);
-    // image x--> right
-    //       |
-    //       y
-    // space: y up , x right , z back, -z front
-    let viewport_v = Vec3::new(0.0, -viewport_height, 0.0);
-
-    // width per pix
-    let viewport_u_delta = viewport_u / (image_width as f32);
-    // height per pix
-    let viewport_v_delta = viewport_v / (image_height as f32);
-
-    // camerea position
-    let camera_center = Point::new(0.0, 0.0, 0.0);
-    // -z  1.0  viewport to camera
-    let focal_length = Vec3::new(0.0, 0.0, -1.0);
-    // camera position --> viewport center ---> top center --> top left
-    let viewport_top_left_pixel = camera_center + focal_length - viewport_u / 2.0 - viewport_v / 2.0;
-    // padding 0.5* delta u/v
-    let viewport_top_left_pixel_center = viewport_top_left_pixel - viewport_u_delta / 2.0 - viewport_v_delta / 2.0;
-
-    let ppm_content = gen_ray_ppm_p3(image_width, image_height, camera_center, viewport_top_left_pixel_center, viewport_u_delta, viewport_v_delta);
-
-    write_image(ppm_content, "./target/ray_scene_render.ppm".to_string())
-}
-
-
-fn gen_gradient_ppm() {
-    let ppm_content = gen_gradient_ppm_p3(400, 225);
-
-    let v1 = Vec3::new(1.0, 1.0, 1.0);
-    let v2 = Vec3::new(1.0, 1.0, 1.0);
-
-    println!("v: {:#} + {:#} => {:#}", v1, v2, v1 + v2);
-    println!("v: {:#} + {:#} => {:#}", v1, v2, v1 - v2);
-    println!("v: {:#} + {:#} => {:#}", v1, v2, v1.dot(v2));
-    println!("v: {:#} + {:#} => {:#}", v1, v2, v1.cross(v2));
-    println!("color: {:#}", Color::new(0.3, 0.4, 1.0).to_color());
-    println!("point: {:#}", Point::new(1.0, 1.0, 1.0));
-    let ray = Ray::new(Point::new(1.0, 1.0, 1.0), Vec3 { x: 0.0, y: 1.0, z: 0.0 });
-    println!("Ray: {:#} => {:#}", ray, ray.at(2.0));
-
-    write_image(ppm_content, "./target/gen_gradient_ppm.ppm".to_string())
 }

src/point.rs

@@ -1,4 +0,0 @@
-use crate::vec3;
-
-pub type Point = vec3::Vec3;
-

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 {

src/sphere.rs

@@ -0,0 +1,41 @@
+use crate::hittable;
+use crate::types_defined::{HitRecord, Point, Ray, Sphere};
+
+impl Sphere {
+    pub fn new(c: Point, r: f32) -> Self {
+        Self {
+            center: c,
+            radius: r,
+        }
+    }
+}
+
+impl hittable::Hittable for Sphere {
+    fn hit(self, r: &Ray, t_min: f32, t_max: f32) -> HitRecord {
+        let a: f32 = r.direction.length_squared();
+        let h = r.direction.dot(self.center - r.point);
+        // let b = -2.0 * r.direction.dot(sphere_center - r.point);
+        let c = (self.center - r.point).length_squared() - self.radius * self.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;
+
+        let mut root = near;
+        if root <= t_min || root >= t_max {
+            root = far;
+            if root <= t_min || root >= t_max {
+                root = -1.0;
+            }
+        }
+        
+        HitRecord {
+            t: root,
+            p: r.at(root),
+            normal: r.at(root) - self.center,
+        }
+    }
+}

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,
+}

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 {