this repo has no description
added a sphere
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src/ray.zig
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src/ray.zig
···
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}
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pub fn color(self: *Ray) zm.Vec {
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if (hit_sphere(zm.f32x4(0, 0, -1, 0), 0.5, self)) {
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return zm.f32x4(1, 0, 0, 1);
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}
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const unit_direction = zm.normalize3(self.dir);
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const a = 0.5 * (unit_direction[1] + 1.0);
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return zm.f32x4s(1.0 - a) * zm.f32x4s(1.0) + zm.f32x4s(a) * zm.f32x4(0.5, 0.7, 1.0, 1.0);
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}
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fn hit_sphere(center: zm.Vec, radius: f32, r: *Ray) bool {
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const oc = r.orig - center;
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const a = zm.dot3(r.dir, r.dir)[0];
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const b = 2.0 * zm.dot3(oc, r.dir)[0];
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const c = zm.dot3(oc, oc)[0] - radius * radius;
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const discriminant = b * b - 4 * a * c;
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return discriminant >= 0;
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}