tcbrindle/raytracer.hpp

Simple compile-time raytracer using C++17

raytracer.hpp's Issues

Not able to compile

ERROR :

/home/abhi/raytracer.hpp/raytracer.hpp:432:62:   in constexpr expansion of 'rt::cmath::pow(((float)specular), ((int)surf.rt::surface::roughness))'
/home/abhi/raytracer.hpp/raytracer.hpp:79:20:   in constexpr expansion of 'std::pow<float, int>(base, iexp)'
/usr/include/c++/7/cmath:418:17: error: 'pow(2.2191121242940426e-3, 2.5e+2)' is not a constant expression
      return pow(__type(__x), __type(__y));
             ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

How do I fix this?

Can't compile (Clang 7)

I get the following error:

Scanning dependencies of target raytracer-ct
[ 16%] Building CXX object CMakeFiles/raytracer-ct.dir/compile_time.cpp.o
/home/v/compile/raytracer.hpp/compile_time.cpp:78:20: error: constexpr variable 'image' must be initialized by a constant expression
    constexpr auto image = [] {
                   ^       ~~~~
/usr/bin/../lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/cmath:464:12: note: subexpression not valid in a constant expression
  { return __builtin_sqrtf(__x); }
           ^
/home/v/compile/raytracer.hpp/raytracer.hpp:52:12: note: in call to 'sqrt(3.425000e+01)'
    return std::sqrt(val);
           ^
/home/v/compile/raytracer.hpp/raytracer.hpp:117:12: note: in call to 'sqrt(3.425000e+01)'
    return cmath::sqrt(dot(v, v));
           ^
/home/v/compile/raytracer.hpp/raytracer.hpp:122:27: note: in call to 'mag(look_at - pos)'
    return (real_t{1.0} / mag(v)) * v;
                          ^
/home/v/compile/raytracer.hpp/raytracer.hpp:167:23: note: in call to 'norm(look_at - pos)'
              forward{norm(look_at - pos)},
                      ^
/home/v/compile/raytracer.hpp/compile_time.cpp:33:16: note: in call to 'camera(rt::vec3{3., 2., 4.}, rt::vec3{-1., 0.5, 0.})'
    camera cam_{vec3{ 3.0, 2.0, 4.0 }, vec3{ -1.0, 0.5, 0.0 }};
               ^
/home/v/compile/raytracer.hpp/compile_time.cpp:81:18: note: in call to 'static_scene()'
        r.render(static_scene{}, c, c.width, c.height);
                 ^
/home/v/compile/raytracer.hpp/compile_time.cpp:78:28: note: in call to '&[]     {
        rt::ray_tracer r{};
        static_canvas<32, 32> c{};
        r.render((anonymous namespace)::static_scene{}, c, c.width, c.height);
        return c;
    }
->operator()()'
    constexpr auto image = [] {
                           ^
1 error generated.

Square root infinite loop

In rt::sqrt when NaN is passed to val, it will be in an infinite loop.

Use propper way to enable C++17

Right way is to use CMAKE_CXX_STANDARD and not an option -std=c++1z directly.

Reflections do not look right in my opinion

If there are too many ray bounces, the color result is an average of the albedo and grey, which does not look right in my opinion. I tried setting reflection to the current albedo, if there were too many bounces.

Before

0 bounces

1 bounce

2 bounces

3 bounces

4 bounces

5 bounces

6 bounces

7 bounces

8 bounces

After

0 bounces

1 bounce

2 bounces

3 bounces

4 bounces

5 bounces

6 bounces

7 bounces

8 bounces

incorrect pow implementation

You can compare pow(2, 3) and std::pow(2, 3) for instance.