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add Metal material

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This commit is contained in:
Fabien Freling 2021-05-11 22:52:51 +02:00
parent b3c47a914f
commit bc3fb54991
3 changed files with 45 additions and 11 deletions
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36
in_one_weekend/src/material.zig
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@ -8,6 +8,7 @@ const HitRecord = @import("hittable.zig").HitRecord;
pub const MaterialType = enum {
Lambertian,
Metal,
};
pub const Material = struct {
@ -21,15 +22,34 @@ pub const ScatteredRay = struct {
};
pub fn scatter(ray: Ray, hit: HitRecord, rng: *Random) ?ScatteredRay {
var scatterDirection = hit.normal.add(vec3.random_unit_vector(rng));
const scatteredDirection = switch (hit.material.materialType) {
// Catch degenerate scatter direction
if (scatterDirection.nearZero()) {
scatterDirection = hit.normal;
.Lambertian => blk: {
var scatterDirection = hit.normal.add(vec3.random_unit_vector(rng));
// Catch degenerate scatter direction
if (scatterDirection.nearZero()) {
scatterDirection = hit.normal;
}
break :blk scatterDirection;
},
.Metal => blk: {
const reflected = ray.direction.unit().reflect(hit.normal);
const scattered = Ray{ .origin = hit.p, .direction = reflected };
if (scattered.direction.dot(hit.normal) <= 0) {
break :blk null;
}
break :blk scattered.direction;
},
};
if (scatteredDirection) |dir| {
return ScatteredRay{
.ray = Ray{ .origin = hit.p, .direction = dir},
.color = hit.material.color,
};
}
return ScatteredRay{
.ray = Ray{ .origin = hit.p, .direction = scatterDirection},
.color = hit.material.color,
};
return null;
}