added comparison

interfaces/Crafter.Math-Intersection.cppm

@@ -0,0 +1,124 @@
+/*
+Crafter®.Math
+Copyright (C) 2026 Catcrafts®
+catcrafts.net
+
+This library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Lesser General Public
+License version 3.0 as published by the Free Software Foundation;
+
+This library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with this library; if not, write to the Free Software
+Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
+*/
+
+export module Crafter.Math:Intersection;
+import :Vector;
+import std;
+
+namespace Crafter {
+    export template<typename T>
+	constexpr T IntersectionTestRayTriangle(Vector<T, 3, 0> vert0, Vector<T, 3, 0> vert1, Vector<T, 3, 0> vert2, Vector<T, 3, 0> rayOrigin, Vector<T, 3, 0> rayDir) {
+        Vector<T, 3, 0> edge1 = vert1 - vert0;
+        Vector<T, 3, 0> edge2 = vert2 - vert0;
+
+        Vector<T, 3, 0> h = Vector<T, 3, 0>::Cross(rayDir, edge2);
+        T determinant = Vector<T, 3, 0>::Dot(edge1, h);
+
+        if (determinant <= std::numeric_limits<T>::epsilon())  {
+            return std::numeric_limits<T>::max();
+        }
+
+        T inverse_determinant = T(1) / determinant;
+
+        Vector<T, 3, 0> origins_diff_vector = rayOrigin - vert0;
+        T u =  Vector<T, 3, 0>::Dot(origins_diff_vector, h) * inverse_determinant;
+
+        if (u < 0.0 || u > 1.0)
+        {
+            return std::numeric_limits<T>::max();
+        }
+
+        Vector<T, 3, 0> q = Vector<T, 3, 0>::Cross(origins_diff_vector, edge1);
+        T v = inverse_determinant * Vector<T, 3, 0>::Dot(rayDir, q);
+
+        if (v < 0.0 || u + v > 1.0) {
+            return std::numeric_limits<T>::max();
+        }
+
+        return inverse_determinant * Vector<T, 3, 0>::Dot(edge2, q);
+    }
+
+    export template<typename T>
+    constexpr T IntersectionTestRaySphere(Vector<T, 3, 0> position, T radius, Vector<T, 3, 0> rayOrigin, Vector<T, 3, 0> rayDir) {
+        T a = Vector<T, 3, 0>::Dot(rayDir, rayDir);
+        T b = Vector<T, 3, 0>::Dot(rayDir, (T(2) * (rayOrigin - position)));
+        T c = Vector<T, 3, 0>::Dot(position, position) + Vector<T, 3, 0>::Dot(rayOrigin, rayOrigin) - T(2) * Vector<T, 3, 0>::Dot(rayOrigin, position) - radius * radius;
+        T d = b * b + (T(-4)) * a * c;
+
+        if (d < 0) {
+            return std::numeric_limits<T>::max();
+        }
+
+        d = std::sqrt(d);
+
+        float t = (T(-0.5)) * (b + d) / a;
+        if (t > T(0)) {
+            return t;
+        } else {
+            return std::numeric_limits<T>::max();
+        }
+    }
+
+    export template<typename T>
+    constexpr T IntersectionTestRayOrientedBox(Vector<T, 3, 0> boxPosition, Vector<T, 3, 0> boxSize, Vector<T, 4, 0> boxRotation, Vector<T, 3, 0> rayOrigin, Vector<T, 3, 0> rayDir) {
+        Vector<T, 4, 0> invRot(
+            -boxRotation.x,
+            -boxRotation.y,
+            -boxRotation.z,
+            boxRotation.w
+        );
+
+        Vector<T, 3, 0> localOrigin = Vector<T, 3, 0>::Rotate(rayOrigin - boxPosition, invRot);
+        Vector<T, 3, 0> localDir    = Vector<T, 3, 0>::Rotate(rayDir, invRot);
+
+        Vector<T,3,0> halfExtents = boxSize * T(0.5);
+
+        T tMin = T(0);
+        T tMax = std::numeric_limits<T>::max();
+
+        for (std::uint32_t i = 0; i < 3; ++i)
+        {
+            if (std::abs(localDir.v[i]) < std::numeric_limits<T>::epsilon())
+            {
+                if (localOrigin.v[i] < -halfExtents.v[i] || localOrigin.v[i] >  halfExtents.v[i]) {
+                    return std::numeric_limits<T>::max();
+                }
+            }
+            else
+            {
+                T invD = T(1) / localDir.v[i];
+                T t1 = (-halfExtents.v[i] - localOrigin.v[i]) * invD;
+                T t2 = ( halfExtents.v[i] - localOrigin.v[i]) * invD;
+
+                if (t1 > t2) {
+                    std::swap(t1, t2);
+                }
+
+                tMin = std::max(tMin, t1);
+                tMax = std::min(tMax, t2);
+
+                if (tMin > tMax) {
+                    return std::numeric_limits<T>::max();
+                }
+            }
+        }
+
+        return (tMin >= T(0)) ? tMin : tMax;
+    }
+}