CatStation/Content.Client/Atmos/EntitySystems/AtmosphereSystem.Gases.cs

using System.Runtime.CompilerServices;
using Content.Shared.Atmos;

namespace Content.Client.Atmos.EntitySystems;

public sealed partial class AtmosphereSystem
{
    /*
     Partial class for operations involving GasMixtures.

     Any method that is overridden here is usually because the server-sided implementation contains
     code that would escape sandbox. As such these methods are overridden here with a safe
     implementation.
     */

    public override bool IsMixtureFuel(GasMixture mixture, float epsilon = Atmospherics.Epsilon)
    {
        var tmp = new float[Atmospherics.AdjustedNumberOfGases];
        NumericsHelpers.Multiply(mixture.Moles, GasFuelMask, tmp);
        return NumericsHelpers.HorizontalAdd(tmp) > epsilon;
    }

    public override bool IsMixtureOxidizer(GasMixture mixture, float epsilon = Atmospherics.Epsilon)
    {
        var tmp = new float[Atmospherics.AdjustedNumberOfGases];
        NumericsHelpers.Multiply(mixture.Moles, GasOxidizerMask, tmp);
        return NumericsHelpers.HorizontalAdd(tmp) > epsilon;
    }

    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    protected override float GetHeatCapacityCalculation(float[] moles, bool space)
    {
        // Little hack to make space gas mixtures have heat capacity, therefore allowing them to cool down rooms.
        if (space && MathHelper.CloseTo(NumericsHelpers.HorizontalAdd(moles), 0f))
        {
            return Atmospherics.SpaceHeatCapacity;
        }

        // explicit stackalloc call is banned on client tragically.
        // the JIT does not stackalloc this during runtime,
        // though this isnt the hottest code path so it should be fine
        // the gc can eat a little as a treat
        var tmp = new float[moles.Length];
        NumericsHelpers.Multiply(moles, GasSpecificHeats, tmp);
        // Adjust heat capacity by speedup, because this is primarily what
        // determines how quickly gases heat up/cool.
        return MathF.Max(NumericsHelpers.HorizontalAdd(tmp), Atmospherics.MinimumHeatCapacity);
    }
}