Now that your ray tracer generates camera rays, we need to be able to answer the core query in ray tracing: "does this ray hit this object?" Here, you will start by implementing ray-object intersection routines against the two types of objects in the starter code: triangles and spheres. Later, we will use a BVH to accelerate these queries, but for now we consider an intersection test against a single object.
First, take a look at the `rays/object.h` for the interface of `Object` class. An `Object` can be **either** a `Tri_Mesh`, a `Shape`, a BVH(which you will implement in Task 3), or a list of `Objects`. Right now, you will be dealing with `Tri_Mesh`'s case and `Shape`'s case, and you can find the definition for`Triangle` and `Sphere` in `rays/shapes.h` and `rays/tri_mesh.h`, respectively.
First, take a look at the `rays/object.h` for the interface of `Object` class. An `Object` can be **either** a `Tri_Mesh`, a `Shape`, a BVH(which you will implement in Task 3), or a list of `Objects`. Right now, we are only dealing with `Tri_Mesh`'s case and `Shape`'s case, and their interfaces are in `rays/tri_mesh.h` and `rays/shapes.h`, respectively. `Tri_Mesh` contains a BVH of`Triangle`, and in this task you will be working with the `Triangle` class. For `Shape`, you are going to work with `Sphere`s, which is the major type of `Shape` in Scotty 3D.
The `hit` routine that you need to implement (for both `Tri_Mesh` and `Sphere `) takes in a ray, and returns a `Trace` structure, which contains information on whether the ray hits the object and if hits, the information describing the surface at the point of the hit. See `rays/trace.h` for the definition of `Trace`.
Now, you need to implement the `hit` routine for both `Triangle` and `Sphere`. `hit` takes in a ray, and returns a `Trace` structure, which contains information on whether the ray hits the object and if hits, the information describing the surface at the point of the hit. See `rays/trace.h` for the definition of `Trace`.
In order to correctly implement `hit` you need to understand some of the fields in the Ray structure defined in `lib/ray.h`.
