removed phase flips

src/main.cpp

@@ -74,7 +74,7 @@ color pixel_color(const ray& r, const hittable& world, const std::vector<vec3> s
           continue;
         }
         //rays interfere here
-        inner_amp += r.get_amplitude() * std::cos(phase_offset + r.optical_path_to(0.) * 2. * pi / wavelengths[i] + r.get_phaseflips() * pi);
+        inner_amp += r.get_amplitude() * std::cos(phase_offset + r.optical_path_to(0.) * 2. * pi / wavelengths[i]);
       }
       //colour amplitude is intensity
       colour_amplitude += inner_amp * inner_amp;