ft (wip): textures

src/objects/circle.rs

@@ -1,4 +1,4 @@
-use std::sync::Arc;
+use std::{f32::consts::PI, sync::Arc};
 
 use crate::{
     objects::{materials::traits::Material, traits::Hittable},
@@ -45,8 +45,27 @@ impl Hittable for Circle {
 
         let p = r.at(t);
         if (p - self.center).length() < self.radius {
-            return Some(Hit::new(t, p, self.normal, self.material.clone(), self.normal.dot(&r.dir()) < 0.)); 
+            let uv = self.to_uv(&p);
+            return Some(Hit::new(
+                t,
+                p,
+                self.normal,
+                self.material.clone(),
+                self.normal.dot(&r.dir()) < 0.,
+                *uv.x(),
+                *uv.y(),
+            ));
         }
         None
     }
+
+    fn to_uv(&self, point: &Vec3) -> Vec3 {
+        let p = *point - self.center;
+        // TODO: add rotated texture support
+        return Vec3::new(
+            0.5 + p.y().atan2(*p.x()) / (2. * PI),
+            1. - (p.z() / self.radius).acos() / PI,
+            0.0,
+        );
+    }
 }