5.Adding a Sphere

src/image.rs

@@ -1,4 +1,4 @@
-use crate::{ray::Ray, vec3::{self, Vec3}};
+use crate::{point::Point, ray::Ray, vec3::{self, Vec3}};
 
 
 pub type Color = vec3::Vec3;
@@ -10,11 +10,15 @@ impl Color {
     }
 }
 
-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 {
+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 {
-        println!("scan line {}/{} ", j + 1, 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);
@@ -22,9 +26,15 @@ pub fn gen_ray_ppm_p3(width: i32, height: i32, camera_center: Vec3, viewport_top
             let ray_direction = pixel_center - camera_center;
             // ray
             let r = Ray::new(camera_center,  ray_direction);
-            // determind color
-            let color = ray_color(r);
 
+            /*
+             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');
@@ -34,10 +44,64 @@ pub fn gen_ray_ppm_p3(width: i32, height: i32, camera_center: Vec3, viewport_top
     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;
+}
+
+
 /*
 get color of this ray; background
 */
-fn ray_color(r: Ray) -> Color {
+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);

src/main.rs

@@ -4,6 +4,8 @@ use vec3::{Vec3};
 use point::{Point};
 use ray::{Ray};
 
+use crate::image::gen_ray_sphere_ppm_p3;
+
 mod image;
 mod write_file_util;
 mod vec3;
@@ -15,6 +17,45 @@ fn main() {
     println!("==================================");
     ray_scene_render();
     println!("==================================");
+    ray_sphere_scene_render();
+    println!("==================================");
+}
+
+
+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())
 }