Sphere color with constant_medium

[Veigabriel25]

When i tried this code of the book 2 in the book 3, no matter what color I apply it stays black.

shared_ptr<hittable> boundary = make_shared<sphere>(point3(200,150,200), 70, make_shared<dielectric>(1.5)); objects.add(boundary); objects.add(make_shared<constant_medium>(boundary, 0.2, color(1, 1, 1)));

What am i doing wrong??

[trevordblack]

Do you have a light in the scene?
What does your main file look like?

[YohnWang]

Try to set the background to other colours,then see if it changes,if changes,to check the new ray direction in scatter.
Don't write return background; when depth<=0,we should distinguish between depth<=0 and hit anything.
Like this:

colour_t ray_colour(const ray_t &r,const hittable_list_t &world,const colour_t &background={0,0,0},int depth=50)
{
    if(depth<=0)
        return {0,0,0};
    auto [is_hit,rec]=world.hit(r, 0.001, infinity);
    if(is_hit==false)
        return background;
    ...

You also should make a big light sphere to hold everything,if the colour is same as background,to locate the bug.
Good luck.

[Walther]

Possibly related #760

[hollasch]

Good thought @Walther .

[hollasch]

Converting to discussion.