Clumsy non-swept AABB collision system for Player

1 files changed, 33 insertions, 0 deletions

diff --git a/src/Math/Ray.hpp b/src/Math/Ray.hpp
new file mode 100644
index 0000000..f83a2b5
--- /dev/null
+++ b/src/Math/Ray.hpp
@@ -0,0 +1,33 @@
+#pragma once
+
+#include "../Common/Lambda.hpp"
+#include "AABB.hpp"
+#include "Vector.hpp"
+
+struct Ray {
+    struct RaycastResult {
+        Bool hit = false;
+        Vec3 point;
+        Vec3 normal;
+    };
+
+    // https://gdbooks.gitbooks.io/3dcollisions/content/Chapter3/raycast_aabb.html
+    RaycastResult cast(AABB box) const {
+        Vec3 t_from = (box.min - origin) / direction;
+        Vec3 t_to = (box.max - origin) / direction;
+
+        Real t_min = t_from.zip(t_to, LAMBDA(std::min, 2)).reduce(LAMBDA(std::max, 2));
+        Real t_max = t_from.zip(t_to, LAMBDA(std::max, 2)).reduce(LAMBDA(std::min, 2));
+
+        if (t_max < 0 || t_min > t_max) return {};
+
+        return {
+            .hit = true,
+            .point = origin + direction * t_min,
+            .normal = t_from.zip(t_to, [](auto a, auto b) { return a < b ? -1.0 : 1.0; })
+        };
+    }
+
+    Vec3 origin;
+    Vec3 direction;
+};