7.Moving Camera Code Into Its Own Class

8.Antialiasing

src/camera.rs

@@ -1,5 +1,8 @@
 use crate::hittable::HittableList;
+use crate::math_utils::clamp;
 use crate::types_defined::{Camera, Color, Point, Ray, Vec3};
+use rand::rngs::ThreadRng;
+use rand::{Rng, thread_rng};
 
 impl Camera {
     pub fn new(
@@ -8,6 +11,7 @@ impl Camera {
         viewport_height: f32,
         camera_center: Point,
         focal_length: Vec3,
+        sample_times: i8,
     ) -> Self {
         let image_height = ((image_width as f32 / aspect_ratio) as i32).max(1);
         let viewport_width = viewport_height * (image_width as f32 / image_height as f32);
@@ -41,6 +45,7 @@ impl Camera {
             viewport_u_delta,
             viewport_v_delta,
             viewport_top_left_pixel_center,
+            sample_times: sample_times,
         }
     }
 
@@ -53,18 +58,30 @@ impl Camera {
             }
 
             for i in 0..self.image_width {
-                // every pixcel's position
-                let pixel_center = self.viewport_top_left_pixel_center
-                    + (i as f32 * self.viewport_u_delta)
-                    + (j as f32 * self.viewport_v_delta);
-                // Vector(camera, pixcel)
-                let ray_direction = pixel_center - self.camera_center;
-                // ray
-                let r = Ray::new(self.camera_center, ray_direction);
-                // determind color
-                let color = self.ray_color(&r, world);
+                // color
+                let mut color = Color::new(0.0, 0.0, 0.0);
+                let rng = &mut thread_rng();
+                for s in 0..self.sample_times {
+                    let bias = self.random_square(rng);
+                    let pix_sample = self.viewport_top_left_pixel_center
+                        + (i as f32 + bias.x) * self.viewport_u_delta
+                        + (j as f32 + bias.y) * self.viewport_v_delta;
+                    let r = Ray::new(self.camera_center, pix_sample - self.camera_center);
+                    let sample_color = self.ray_color(&r, world);
+                    color = color + sample_color;
+                }
+                // color * each sample color
+                color = color * (1.0 / self.sample_times as f32);
+
+                // clamp color rgb
+                let color_clamped = Color::new(
+                    clamp(color.x, 0.0, 1.0),
+                    clamp(color.y, 0.0, 1.0),
+                    clamp(color.z, 0.0, 1.0),
+                );
+
                 // content
-                img_content.push_str(color.to_color().as_str());
+                img_content.push_str(color_clamped.to_color().as_str());
                 img_content.push('\n');
             }
         }
@@ -88,4 +105,9 @@ impl Camera {
         // return background color.
         (1.0 - a) * Color::new(1.0, 1.0, 1.0) + a * Color::new(0.5, 0.7, 1.0)
     }
+
+    // -> [x, y, 0]
+    fn random_square(&self, rng: &mut ThreadRng) -> Vec3 {
+        Vec3::new(rng.gen_range(-0.5..0.1), rng.gen_range(-0.5..0.1), 0.0)
+    }
 }

src/main.rs

@@ -9,6 +9,7 @@ mod sphere;
 mod types_defined;
 mod vec3;
 mod write_file_util;
+mod math_utils;
 
 fn main() {
     camera_render();
@@ -16,11 +17,12 @@ fn main() {
 
 fn camera_render() {
     let camera = Camera::new(
-        800,
+        400,
         16.0 / 9.0,
         2.0,
         Point::new(0.0, 0.0, 0.0),
         Vec3::new(0.0, 0.0, -1.0),
+        10
     );
     // world
     // world objects(spheres)

src/math_utils.rs

@@ -0,0 +1,10 @@
+
+pub fn clamp(value: f32, low: f32, high: f32) -> f32 {
+    if value < low {
+        return low;
+    }
+    if value > high {
+        return high;
+    }
+    return value;
+}

src/types_defined.rs

@@ -41,6 +41,9 @@ pub struct Camera {
     pub viewport_u_delta: Vec3,
     pub viewport_v_delta: Vec3,
     pub viewport_top_left_pixel_center: Vec3,
+
+    // sample times
+    pub sample_times: i8
 }
 
 /*