1 files changed, 98 insertions, 0 deletions
diff --git a/editor/tests/raycast-test.cpp b/editor/tests/raycast-test.cpp
new file mode 100644
index 00000000..549760c3
--- /dev/null
+++ b/editor/tests/raycast-test.cpp
@@ -0,0 +1,98 @@
+#include "../tests-private.hpp"
+#include <array>
+#include <Magnum/Math/Functions.h>
+#include <Magnum/Math/Vector2.h>
+
+namespace floormat::tests {
+
+namespace {
+
+struct aabb_result
+{
+    Vector2 ts;
+    float tmin, tmax;
+    bool result;
+};
+
+std::array<uint8_t, 2> ray_aabb_signs(Vector2 ray_dir_inv_norm)
+{
+    bool signs[2];
+    for (unsigned d = 0; d < 2; ++d)
+        signs[d] = std::signbit(ray_dir_inv_norm[d]);
+    return { signs[0], signs[1] };
+}
+
+// https://tavianator.com/2022/ray_box_boundary.html
+//
+aabb_result ray_aabb_intersection(Vector2 ray_origin, Vector2 ray_dir_inv_norm,
+                                  std::array<Vector2, 2> box_minmax, std::array<uint8_t, 2> signs)
+{
+    using Math::min;
+    using Math::max;
+
+    float ts[2];
+    float tmin = 0, tmax = 16777216;
+
+    for (unsigned d = 0; d < 2; ++d)
+    {
+        float bmin = box_minmax[signs[d]][d];
+        float bmax = box_minmax[!signs[d]][d];
+
+        float dmin = (bmin - ray_origin[d]) * ray_dir_inv_norm[d];
+        float dmax = (bmax - ray_origin[d]) * ray_dir_inv_norm[d];
+
+        ts[d] = dmin;
+        tmin = max(dmin, tmin);
+        tmax = min(dmax, tmax);
+    }
+
+    return { {ts[0], ts[1] }, tmin, tmax, tmin < tmax };
+}
+
+} // namespace
+
+struct raycast_test : base_test
+{
+    ~raycast_test() noexcept override;
+
+    bool handle_key(app& a, const key_event& e, bool is_down) override
+    {
+        return false;
+    }
+
+    bool handle_mouse_click(app& a, const mouse_button_event& e, bool is_down) override
+    {
+        return false;
+    }
+
+    bool handle_mouse_move(app& a, const mouse_move_event& e) override
+    {
+        return false;
+    }
+
+    void draw_overlay(app& a) override
+    {
+
+    }
+
+    void draw_ui(app& a, float width) override
+    {
+
+    }
+
+    void update_pre(app& a) override
+    {
+
+    }
+
+    void update_post(app& a) override
+    {
+
+    }
+};
+
+raycast_test::~raycast_test() noexcept = default;
+
+Pointer<base_test> tests_data::make_test_raycast() { return Pointer<raycast_test>{InPlaceInit}; }
+
+} // namespace floormat::tests