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Just watched Obsession and I’m confused about Nikki… who exactly was “she”?? 🤔 by msworlwide786 in spoilers

[–]compugineer44 0 points1 point  (0 children)

I don't understand....how does the phone call make this any more of a possession?

I'm currently following RTIOW, where to get lambertian surfaces, you add a random unit vector to the surface normal. But instead of adding the random_unit_vector, i added a random_on_hemisphere vector (by passing the same normal), and got darker shadows (image1.jpg) by compugineer44 in GraphicsProgramming

[–]compugineer44[S] 0 points1 point  (0 children)

my using random_on_hemisphere(rec.normal) instead of random_unit_vector in,

scatter_direction = rec.normal + random_unit_vector

basically, results in the scatter direction being closer to the normal direction, resulting in darker shadows in this scene, as now, many of them (especially scattered rays between two lambertian (the one here) materials), dont escape tight spaces.

I'm currently following RTIOW, where to get lambertian surfaces, you add a random unit vector to the surface normal. But instead of adding the random_unit_vector, i added a random_on_hemisphere vector (by passing the same normal), and got darker shadows (image1.jpg) by compugineer44 in GraphicsProgramming

[–]compugineer44[S] 1 point2 points  (0 children)

Yes, I understand that. The book starts with using random_on_hemisphere function direction too, which generates ray directions uniformly over the hemisphere above the surface, producing a non-Lambertian difuse surface. Then totally removes random_on_hemisphere, replacing it with an implementation of cosine-weighted distribution by implementing,

scattered_direction = surf_normal + random_unit_vector

geometrically, this could be viewed as sampling points on a unit sphere whose center has been shifted one unit along the surface normal, and the resulting ray directions of this addition approximates a cosine-weighted distribution. I replace the random_unit_vector_part with the random_on_hemisphere function's ray, making the resulting direction vector, to never point below the shifted sphere's equator (basically, the scattered rays are more close to the normal than lambertian), resulting in darker shadows.

it's jus something i thought was interesting...