From 11245af1122a2f5cf8c0dd399b3d8a4747d49c09 Mon Sep 17 00:00:00 2001
From: dengqn <someonedeng@qq.com>
Date: Sat, 9 Aug 2025 01:19:01 +0800
Subject: [PATCH] chore: hit record

---
 src/camera.rs   | 18 +++++++++---------
 src/hittable.rs | 39 +++++++++++++++++++++++++--------------
 src/main.rs     |  2 +-
 src/sphere.rs   | 18 +++++++++---------
 4 files changed, 44 insertions(+), 33 deletions(-)

diff --git a/src/camera.rs b/src/camera.rs
index 6040577..ab556af 100644
--- a/src/camera.rs
+++ b/src/camera.rs
@@ -4,7 +4,7 @@ use std::io::{BufWriter};
 use crate::hittable::HittableList;
 use crate::math_utils::clamp;
 use crate::ppm_writer::PPMWriter;
-use crate::types_defined::{Camera, Color, Point, Ray, Vec3};
+use crate::types_defined::{Camera, Color, HitRecord, Point, Ray, Vec3};
 use rand::rngs::ThreadRng;
 use rand::{Rng, thread_rng};
 
@@ -89,11 +89,6 @@ impl<'a> Camera<'a> {
                 );
 
                 self.ppm_file_writer.write(color.to_color());
-
-                
-                // content
-                // img_content.push_str(&color_clamped.to_color_str().as_str());
-                // img_content.push('\n');
             }
         }
 
@@ -108,11 +103,16 @@ impl<'a> Camera<'a> {
         }
 
         // 限制出射光线的角度（0.001经验值）
-        let hr = world.hit(&ray, 0.001, f32::MAX);
-        if hr.t >= 0.0 {
+        let hit_record = &mut HitRecord{
+            t: 0.0,
+            normal: Vec3::new(0.0, 0.0, 0.0),
+            front_face: false,
+        };
+        let hit = world.hit(&ray, 0.001, f32::MAX, hit_record);
+        if hit_record.t >= 0.0 {
             // diffuse normal vec
             let diffuse_vec = Vec3::random_unit();
-            let lambertian_vec = diffuse_vec + hr.normal;
+            let lambertian_vec = diffuse_vec + hit_record.normal;
             // 每次反射按0.5计算颜色（反射率 ）
             return 0.5 * self.ray_color(&Ray::new(ray.point, lambertian_vec), depth - 1, world);
         }
diff --git a/src/hittable.rs b/src/hittable.rs
index 4089645..070f451 100644
--- a/src/hittable.rs
+++ b/src/hittable.rs
@@ -1,7 +1,7 @@
 use crate::types_defined::{HitRecord, Ray, Vec3};
 
 pub trait Hittable {
-    fn hit(&self, r: &Ray, t_min: f32, t_max: f32) -> HitRecord;
+    fn hit(&self, r: &Ray, t_min: f32, t_max: f32, hit_record: &mut HitRecord) -> bool;
 }
 
 
@@ -19,22 +19,33 @@ impl HittableList {
         let _ = &self.objects.push(object);
     }
 
-    pub fn hit(&self, r: &Ray, t_min: f32, t_max: f32) -> HitRecord {
+    pub fn hit(&self, r: &Ray, t_min: f32, t_max: f32, hit_record: &mut HitRecord) -> bool {
+
+        let mut hits = false;
+        let mut closest_so_far = t_max;
+
+        let temp_hit_record = &mut HitRecord{
+            t: 0.0,
+            normal: Vec3::new(0.0, 0.0, 0.0),
+            front_face: false,
+        };
+
         for object in &self.objects {
-            let temp = object.hit(r, t_min, t_max);
-            if temp.t >= 0.0 {
-                return temp
+            let hit = object.hit(r, t_min, closest_so_far, temp_hit_record);
+            if hit {
+                hits = true;
+                closest_so_far = temp_hit_record.t;
+
+                hit_record.t = temp_hit_record.t;
+                hit_record.front_face = temp_hit_record.front_face;
+                hit_record.normal = temp_hit_record.normal;
+                if temp_hit_record.t >= 0.0 {
+                    return true;
+                }
             }
         }
-        HitRecord {
-            t: -1.0,
-            normal: Vec3 {
-                x: 0.0,
-                y: 0.0,
-                z: 0.0,
-            },
-            front_face: false,
-        }
+
+        hits
     }
 }
 
diff --git a/src/main.rs b/src/main.rs
index e6456cc..7f644fa 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -37,7 +37,7 @@ fn camera_render() {
         width,
         16.0 / 9.0,
         2.0,
-        Point::new(0.0, 0.0, 0.0),
+        Point::new(0.0, 0.0, 1.0),
         Vec3::new(0.0, 0.0, -1.0),
         50,
         50,
diff --git a/src/sphere.rs b/src/sphere.rs
index 9261dc9..388efa0 100644
--- a/src/sphere.rs
+++ b/src/sphere.rs
@@ -11,7 +11,7 @@ impl Sphere {
 }
 
 impl hittable::Hittable for Sphere {
-    fn hit(&self, r: &Ray, t_min: f32, t_max: f32) -> HitRecord {
+    fn hit(&self, r: &Ray, t_min: f32, t_max: f32, hit_record: &mut HitRecord) -> bool {
         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);
@@ -28,19 +28,19 @@ impl hittable::Hittable for Sphere {
         if root <= t_min || root >= t_max {
             root = far;
             if root <= t_min || root >= t_max {
-                root = -1.0;
+                // hit_record.t = -1.0;
+                return false
             }
         }
 
         let p = r.at(root);
         let normal = (p - self.center) / self.radius;
-        HitRecord {
-            t: root,
-            // p,
-            normal,
-            // check if r.p inside(>=0) the sphere.
-            front_face: r.direction.dot(normal) < 0.0,
-        }
+
+        hit_record.t = root;
+        hit_record.normal = normal;
+        hit_record.front_face = r.direction.dot(normal) < 0.0;
+
+        true
     }
 }
     
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