Raytracer based on Whitted, 1980 paper.

Build instructions: install the dependencies and use cmake.

Depends on SDL and CUDA.

The room scene showing the refractions and reflections for thin and dense objects (shadows are disabled, only the blue ball supports it).

Two primitives implemented so far:

• Triangle
• Sphere

The readme uses the primitive and object terms interchangeably.

Entry point: app.cc.

The display_sdl.cc manages the drawing to the Qt canvas and also handles the keyboard input to the worker thread (world can be rotated using the arrows).

The worker thread calls the Renderer.render() in the render.cc once it receives a re-render signal from the environment.

The renderer sets up the viewport at initialization, and instantiates a Scene object in the constructor (the RoomScene is the only scene that is added in the room_scene.cc).

A Scene object has a buildScene method that instantiates the primitives using the Models helper class (only boxes and squares can be built using triangles) and the lights. The scene has the responsibility to intersect the ojbects in the scene using the trace() method (since it has the knowledge where the objects are for exaple, space partitioning algorithms should go here). It casts a ray and matches the closest object. The reference to the primitive is determined by a lookup based on the list of primitives in the scene and the matched object's excite function is called to determine its color at the intersection point.

Each object has a virtual excite method that receives the incoming Ray object, the Intersection struct (that contains the intersection info such as surface intersection point, surface normal at the intersection), and also, a weak pointer to a Scene object that can be used to recursively cast further rays to intersect other objects (this is a cyclyc dependence, but the reference to the Scene object will not be stored).

How a primitive determines its color is depend on the particular Shader object assigned to the primitive using the setShader() method when building the scene. For example, a Triangle accepts a TriangleShader while a Sphere receives a SphereShader to react to the incoming ray. The excite() function forwards the parameters to the shader, hence the user can prepare the object to react to the incoming radiation. The Shader base class contain helper methods to determine the reflective and refractive ray directions. (The code to determine the diffuse component is implemented in the Scene because the lights should be considered to properly handle the shadows). An example shader, the GenericTriangleShader is implemented to handle the reflection and the refraction. For the Sphere, a similar shader is added, but it is a bit more complicated because it is a dense object so the normals should be adjusted for refraction when the ray is entering or leaving the object.

The user can freely implement new custom shaders for better simulation.