From c3d6d80fd757bcaba266f773c75b49f7e03932bb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonas=20R=C3=B6ger?= <jonas.roeger@tu-dortmund.de>
Date: Wed, 20 Nov 2024 13:41:18 +0100
Subject: [PATCH] fix(scene): respect t for shadow rays

---
 src/raytracer/scene.rs | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/raytracer/scene.rs b/src/raytracer/scene.rs
index 1c4a79b..e9e8c84 100644
--- a/src/raytracer/scene.rs
+++ b/src/raytracer/scene.rs
@@ -94,15 +94,18 @@ impl Scene {
 
         for light in &self.lights {
             // Cast Shadow-Ray
+            let direction = light.position - isect_pt;
+            let distance = direction.norm();
+            let direction = direction / distance;
             let shadow_ray = Ray {
                 origin: isect_pt,
-                direction: (light.position - isect_pt).normalize(),
+                direction,
             };
-            if self
-                .objects
-                .iter()
-                .any(|obj| obj.intersect(&shadow_ray).is_some())
-            {
+            if self.objects.iter().any(|obj| {
+                obj.intersect(&shadow_ray)
+                    .and_then(|(_, _, t, _)| Some(t < distance))
+                    .unwrap_or(false)
+            }) {
                 continue;
             }