From 95827a4a52bcc96f28f6d3e04c87476ce8365dd2 Mon Sep 17 00:00:00 2001
From: Bill Thiede <git@xinu.tv>
Date: Sun, 29 Jan 2023 09:05:16 -0800
Subject: [PATCH] rtiow: descend both children in BVHTriangles::hit.

---
 rtiow/renderer/src/bvh_triangles.rs | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/rtiow/renderer/src/bvh_triangles.rs b/rtiow/renderer/src/bvh_triangles.rs
index f7e7246..4775d8d 100644
--- a/rtiow/renderer/src/bvh_triangles.rs
+++ b/rtiow/renderer/src/bvh_triangles.rs
@@ -194,13 +194,15 @@ where
                 }
             }
         } else {
-            let hr = self.intersect_bvh(r, node.left_child, t_min, t_max);
-            if hr.is_some() {
-                return hr;
-            }
-            let hr = self.intersect_bvh(r, node.left_child + 1, t_min, t_max);
-            if hr.is_some() {
-                return hr;
+            let r1 = self.intersect_bvh(r, node.left_child, t_min, t_max);
+            let r2 = self.intersect_bvh(r, node.left_child + 1, t_min, t_max);
+            // Merge results, if both hit, take the one closest to the ray origin (smallest t
+            // value).
+            match (&r1, &r2) {
+                (Some(_), None) => return r1,
+                (None, Some(_)) => return r2,
+                (None, None) => (),
+                (Some(rp1), Some(rp2)) => return if rp1.t < rp2.t { r1 } else { r2 },
             }
         }
         None
@@ -282,7 +284,7 @@ fn ray_triangle_intersect_moller_trumbore(r: Ray, tri: &Triangle) -> Option<RayT
     if t > EPSILON {
         return Some(RayTriangleResult {
             t,
-            p: r.origin + r.direction * t,
+            p: r.point_at_parameter(t),
         });
     }
     None