950b0e3ddc
The mutation table let the guard's removal survive: with saturate's NaN rule (max(0, NaN) = 0) a zero-lifetime cloud has no opacity without it, and ACloudWithNoLifetimeObscuresNothing still pins that behaviour. Builds. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
32 lines
1.3 KiB
C#
32 lines
1.3 KiB
C#
using CultMath;
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using static CultMath.math;
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using float2 = CultMath.float2;
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// A vented vapour cloud: a free-floating disc that thins every sensor sight line through it. Not an Entity,
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// never priced or rolled, never saved. Zone.Vent is the only adder and Zone's cloud step the only remover;
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// Zone.Obscuration is the one reader detection uses.
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public sealed class VapourCloud
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{
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public FloatingBodyId Id;
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public KinematicBody Body;
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public double VentedAt;
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public float Lifetime;
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public float Radius;
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// The opacity at the moment of venting; it fades linearly to nothing over Lifetime.
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public float Opacity;
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public Entity Venter;
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// A cloud with no lifetime divides by zero; saturate maps the NaN and the infinity to nothing left.
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public float OpacityAt(double now) =>
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saturate(Opacity) * saturate(1f - (float) (now - VentedAt) / Lifetime);
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// Whether the segment a-b reaches the disc: the closest point of the segment to the centre lies within the
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// radius. A cloud past either end of the segment touches it only if it is near that end.
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public bool Touches(float2 a, float2 b)
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{
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var ab = b - a;
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var length2 = lengthsq(ab);
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var t = length2 > 0f ? saturate(dot(Body.Position - a, ab) / length2) : 0f;
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return lengthsq(Body.Position - (a + ab * t)) <= Radius * Radius;
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}
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}
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