12.2.Positioning and Orienting the Camera

src/camera.rs

@@ -14,13 +14,15 @@ impl<'a> Camera<'a> {
         fov: f32,
         image_width: i32,
         aspect_ratio: f32,
-        camera_center: Point,
-        focal_length: f32,
+        center: Point,
+        look_at: Point,
+        v_up: Vec3,
         sample_times: i8,
         reflect_depth: i8,
         ppm_file_writer: &'a mut PPMWriter<BufWriter<File>>
     ) -> Self {
 
+       let focal_length = (look_at - center).length();
 
        let theta = degrees_to_radians(fov);
        let h = f32::tan(theta / 2.);
@@ -29,18 +31,24 @@ impl<'a> Camera<'a> {
         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);
 
-        let viewport_u = Vec3::new(viewport_width, 0.0, 0.0);
+
+        let  w = (center - look_at).normalize();
+        let  u = v_up.cross(w).normalize();
+        let  v = w.cross(u);
+
+
+        let viewport_u = viewport_width * u;
         // image x--> right
         //       |
         //       y
         // space: y up , x right , z back, -z front
-        let viewport_v = Vec3::new(0.0, -viewport_height, 0.0);
+        let viewport_v = viewport_height * (-1. * v);
         // 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);
         let viewport_top_left_pixel =
-            camera_center - Vec3::new(0., 0., focal_length) - viewport_u / 2.0 - viewport_v / 2.0;
+            center - focal_length * w - 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;
@@ -51,7 +59,9 @@ impl<'a> Camera<'a> {
             // aspect_ratio,
             // viewport_width,
             // viewport_height,
-            camera_center,
+            center,
+            look_at,
+            v_up,
             // focal_length,
             // viewport_u,
             // viewport_v,
@@ -81,7 +91,7 @@ impl<'a> Camera<'a> {
                     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 r = Ray::new(self.center, pix_sample - self.center);
                     let sample_color = self.ray_color(&r, self.reflect_depth, world);
                     color = color + sample_color;
                 }

src/main.rs

@@ -22,11 +22,11 @@ fn main() {
 
 fn camera_render() {
 
-    let fov: f32 = 90.;
+    let fov: f32 = 60.;
     let scale = 1;
     let width: i32 = 800/scale;
     let height: i32 = 600/scale;
-    let sample_times = 20;
+    let sample_times = 50;
     let reflect_depth = 20;
 
 
@@ -44,8 +44,9 @@ fn camera_render() {
         fov,
         width,
         width as f32 / height as f32,
-        Point::new(0.0, -0.0, 0.0),
-        1.0,
+        Point::new(-2.0, 0.0, -1.0),
+        Point::new(0.0, 0.0, -1.0),
+        Vec3::new(0., 1., 0.),
         sample_times,
         reflect_depth,
         pw

src/types_defined.rs

@@ -1,5 +1,5 @@
 use std::{fs::File, io::{BufWriter}};
-use crate::material::{MaterialKind};
+use crate::{material::MaterialKind, vec3};
 use crate::ppm_writer::PPMWriter;
 
 /*
@@ -37,7 +37,9 @@ pub struct Camera<'a> {
     // pub aspect_ratio: f32,
     // pub viewport_width: f32,
     // pub viewport_height: f32,
-    pub camera_center: Point,
+    pub center: Point,
+    pub look_at: Point,
+    pub v_up: Vec3,
     // pub focal_length: Vec3,
     // pub viewport_u: Vec3,
     // pub viewport_v: Vec3,