feat(core): add camera view-frustum culling planes

core/include/vf/Frustum.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#include "Math.h"
+#include "Physics.h"
+
+namespace vf {
+
+struct Plane {
+    float nx = 0.0f, ny = 0.0f, nz = 0.0f, d = 0.0f;
+};
+
+class Frustum {
+public:
+    // Extracts the six clip planes from a view-projection matrix
+    // (Gribb and Hartmann). Planes point inward; a point is inside when its
+    // signed distance to every plane is non-negative.
+    static Frustum fromMatrix(const Mat4& viewProjection);
+
+    bool containsPoint(const Vec3& p) const;
+    bool intersectsAabb(const Aabb& box) const;
+
+    const Plane& plane(int i) const { return planes[i]; }
+
+private:
+    Plane planes[6];
+};
+
+} // namespace vf