improved traceline

source/collision/LineTracer.cpp

@@ -8,33 +8,56 @@ namespace omath::collision
 {
     bool LineTracer::CanTraceLine(const Ray &ray, const Triangle3d &triangle)
     {
+        return GetRayHitPoint(ray, triangle) == ray.end;
+    }
+    Vector3 Ray::DirectionVector() const
+    {
+        return end - start;
+    }
+
+    Vector3 Ray::DirectionVectorNormalized() const
+    {
+        return DirectionVector().Normalized();
+    }
+
+    std::optional<Vector3> LineTracer::GetRayHitPoint(const Ray &ray, const Triangle3d &triangle)
+    {
+        constexpr float kEpsilon = std::numeric_limits<float>::epsilon();
+
         const auto sideA = triangle.SideAVector();
         const auto sideB = triangle.SideBVector();
 
-        const auto rayDir = ray.end - ray.start;
+
+        const auto rayDir = ray.DirectionVector();
 
         const auto p = rayDir.Cross(sideB);
-
         const auto det = sideA.Dot(p);
 
-        if (std::abs(det) < 1e-6)
-            return true;
 
-        const auto invDet = 1 / det;
+        if (std::abs(det) < kEpsilon)
+            return ray.end;
 
+        const auto invDet = 1.0f / det;
         const auto t = ray.start - triangle.m_vertex2;
-
         const auto u = t.Dot(p) * invDet;
 
-        if (u < 0.f || u > 1.f)
-            return true;
+
+        if ((u < 0 && std::abs(u) > kEpsilon) || (u > 1 && std::abs(u-1) > kEpsilon))
+            return ray.end;
 
         const auto q = t.Cross(sideA);
         const auto v = rayDir.Dot(q) * invDet;
 
-        if (v < 0.f || u + v > 1.f)
-            return true;
 
-        return sideB.Dot(q) * invDet <= 0.f;
+        if ((v < 0 && std::abs(v) > kEpsilon) || (u + v > 1 && std::abs(u + v - 1) > kEpsilon))
+            return ray.end;
+
+        const auto tHit = sideB.Dot(q) * invDet;
+
+
+        if (tHit <= kEpsilon)
+            return ray.end;
+
+        return ray.start + rayDir * tHit;
     }
 }