Materials

Previously I started working on my very own ray tracer in C++. I got to render basic shapes and put a checker texture on them.

This time I want to introduce a new concept into the code, materials.

Debug color

Each object looks the same in my render right now, it would be nice to see where one ends and another begins.

To achieve that I added a material class:

struct Material
{
    Vec4 debug_color;
};

Each object will now have a material as well:

struct Sphere
{
    ...
    Material *mat;
};

I use a raw pointer for the material, meaning its non-owning. So before I populate the objects array I have to create materials, and store them.

Material blue;
...
blue = Material{
    .debug_color = Vec4(.7,.8,.9,0);
};

And then when creating objects:

objects.emplace_back(Sphere{
    ...
    .mat = &blue,
});

Finally the intersection class needs to store the material as well. This is populated when the ray hits an object.

struct Intersection
{
    ...
    Material *mat;
};

With these changes I get a nice colored room:

Future compatibility

Right now the material class only includes the debug color, but later I want to use it to describe more properties of the object.

In the end I would like to be able to create different kinds of materials and combine them, for that I will need a unified approach to all operations done on materials and for now I am not sure what these operations will be.
Sampling an outgoing ray, given the inbound ray is the most important I can think of now.

So for now I decided to roll with a single material class that I will add more members to.