Penumbra/Penumbra/Import/Models/Export/VertexFragment.cs

using System;
using SharpGLTF.Geometry.VertexTypes;
using SharpGLTF.Memory;
using SharpGLTF.Schema2;

namespace Penumbra.Import.Models.Export;

/*
Yeah, look, I tried to make this file less garbage. It's a little difficult.
Realistically, it will need to stick around until transforms/mutations are built
and there's reason to overhaul the export pipeline.
*/

public struct VertexColorFfxiv : IVertexCustom
{
    public IEnumerable<KeyValuePair<string, AttributeFormat>> GetEncodingAttributes()
    {
        // NOTE: We only realistically require UNSIGNED_BYTE for this, however Blender 3.6 errors on that (fixed in 4.0).
        yield return new KeyValuePair<string, AttributeFormat>("_FFXIV_COLOR",
            new AttributeFormat(DimensionType.VEC4, EncodingType.UNSIGNED_SHORT, true));
    }

    public Vector4 FfxivColor;

    public int MaxColors
        => 0;

    public int MaxTextCoords
        => 0;

    private static readonly string[] CustomNames = ["_FFXIV_COLOR"];

    public IEnumerable<string> CustomAttributes
        => CustomNames;

    public VertexColorFfxiv(Vector4 ffxivColor)
        => FfxivColor = ffxivColor;

    public void Add(in VertexMaterialDelta delta)
    { }

    public VertexMaterialDelta Subtract(IVertexMaterial baseValue)
        => new(Vector4.Zero, Vector4.Zero, Vector2.Zero, Vector2.Zero);

    public Vector2 GetTexCoord(int index)
        => throw new ArgumentOutOfRangeException(nameof(index));

    public void SetTexCoord(int setIndex, Vector2 coord)
    { }

    public bool TryGetCustomAttribute(string attributeName, out object? value)
    {
        switch (attributeName)
        {
            case "_FFXIV_COLOR":
                value = FfxivColor;
                return true;

            default:
                value = null;
                return false;
        }
    }

    public void SetCustomAttribute(string attributeName, object value)
    {
        if (attributeName == "_FFXIV_COLOR" && value is Vector4 valueVector4)
            FfxivColor = valueVector4;
    }

    public Vector4 GetColor(int index)
        => throw new ArgumentOutOfRangeException(nameof(index));

    public void SetColor(int setIndex, Vector4 color)
    { }

    public void Validate()
    {
        var components = new[]
        {
            FfxivColor.X,
            FfxivColor.Y,
            FfxivColor.Z,
            FfxivColor.W,
        };
        if (components.Any(component => component < 0 || component > 1))
            throw new ArgumentOutOfRangeException(nameof(FfxivColor));
    }
}

public struct VertexTexture1ColorFfxiv : IVertexCustom
{
    public IEnumerable<KeyValuePair<string, AttributeFormat>> GetEncodingAttributes()
    {
        yield return new KeyValuePair<string, AttributeFormat>("TEXCOORD_0",
            new AttributeFormat(DimensionType.VEC2, EncodingType.FLOAT, false));
        yield return new KeyValuePair<string, AttributeFormat>("_FFXIV_COLOR",
            new AttributeFormat(DimensionType.VEC4, EncodingType.UNSIGNED_SHORT, true));
    }

    public Vector2 TexCoord0;

    public Vector4 FfxivColor;

    public int MaxColors
        => 0;

    public int MaxTextCoords
        => 1;

    private static readonly string[] CustomNames = ["_FFXIV_COLOR"];

    public IEnumerable<string> CustomAttributes
        => CustomNames;

    public VertexTexture1ColorFfxiv(Vector2 texCoord0, Vector4 ffxivColor)
    {
        TexCoord0  = texCoord0;
        FfxivColor = ffxivColor;
    }

    public void Add(in VertexMaterialDelta delta)
    {
        TexCoord0 += delta.TexCoord0Delta;
    }

    public VertexMaterialDelta Subtract(IVertexMaterial baseValue)
        => new(Vector4.Zero, Vector4.Zero, TexCoord0 - baseValue.GetTexCoord(0), Vector2.Zero);

    public Vector2 GetTexCoord(int index)
        => index switch
        {
            0 => TexCoord0,
            _ => throw new ArgumentOutOfRangeException(nameof(index)),
        };

    public void SetTexCoord(int setIndex, Vector2 coord)
    {
        if (setIndex == 0)
            TexCoord0 = coord;
        if (setIndex >= 1)
            throw new ArgumentOutOfRangeException(nameof(setIndex));
    }

    public bool TryGetCustomAttribute(string attributeName, out object? value)
    {
        switch (attributeName)
        {
            case "_FFXIV_COLOR":
                value = FfxivColor;
                return true;

            default:
                value = null;
                return false;
        }
    }

    public void SetCustomAttribute(string attributeName, object value)
    {
        if (attributeName == "_FFXIV_COLOR" && value is Vector4 valueVector4)
            FfxivColor = valueVector4;
    }

    public Vector4 GetColor(int index)
        => throw new ArgumentOutOfRangeException(nameof(index));

    public void SetColor(int setIndex, Vector4 color)
    { }

    public void Validate()
    {
        var components = new[]
        {
            FfxivColor.X,
            FfxivColor.Y,
            FfxivColor.Z,
            FfxivColor.W,
        };
        if (components.Any(component => component < 0 || component > 1))
            throw new ArgumentOutOfRangeException(nameof(FfxivColor));
    }
}

public struct VertexTexture2ColorFfxiv : IVertexCustom
{
    public IEnumerable<KeyValuePair<string, AttributeFormat>> GetEncodingAttributes()
    {
        yield return new KeyValuePair<string, AttributeFormat>("TEXCOORD_0",
            new AttributeFormat(DimensionType.VEC2, EncodingType.FLOAT, false));
        yield return new KeyValuePair<string, AttributeFormat>("TEXCOORD_1",
            new AttributeFormat(DimensionType.VEC2, EncodingType.FLOAT, false));
        yield return new KeyValuePair<string, AttributeFormat>("_FFXIV_COLOR",
            new AttributeFormat(DimensionType.VEC4, EncodingType.UNSIGNED_SHORT, true));
    }

    public Vector2 TexCoord0;
    public Vector2 TexCoord1;
    public Vector4 FfxivColor;

    public int MaxColors
        => 0;

    public int MaxTextCoords
        => 2;

    private static readonly string[] CustomNames = ["_FFXIV_COLOR"];

    public IEnumerable<string> CustomAttributes
        => CustomNames;

    public VertexTexture2ColorFfxiv(Vector2 texCoord0, Vector2 texCoord1, Vector4 ffxivColor)
    {
        TexCoord0  = texCoord0;
        TexCoord1  = texCoord1;
        FfxivColor = ffxivColor;
    }

    public void Add(in VertexMaterialDelta delta)
    {
        TexCoord0 += delta.TexCoord0Delta;
        TexCoord1 += delta.TexCoord1Delta;
    }

    public VertexMaterialDelta Subtract(IVertexMaterial baseValue)
        => new(Vector4.Zero, Vector4.Zero, TexCoord0 - baseValue.GetTexCoord(0), TexCoord1 - baseValue.GetTexCoord(1));

    public Vector2 GetTexCoord(int index)
        => index switch
        {
            0 => TexCoord0,
            1 => TexCoord1,
            _ => throw new ArgumentOutOfRangeException(nameof(index)),
        };

    public void SetTexCoord(int setIndex, Vector2 coord)
    {
        if (setIndex == 0)
            TexCoord0 = coord;
        if (setIndex == 1)
            TexCoord1 = coord;
        if (setIndex >= 2)
            throw new ArgumentOutOfRangeException(nameof(setIndex));
    }

    public bool TryGetCustomAttribute(string attributeName, out object? value)
    {
        switch (attributeName)
        {
            case "_FFXIV_COLOR":
                value = FfxivColor;
                return true;

            default:
                value = null;
                return false;
        }
    }

    public void SetCustomAttribute(string attributeName, object value)
    {
        if (attributeName == "_FFXIV_COLOR" && value is Vector4 valueVector4)
            FfxivColor = valueVector4;
    }

    public Vector4 GetColor(int index)
        => throw new ArgumentOutOfRangeException(nameof(index));

    public void SetColor(int setIndex, Vector4 color)
    { }

    public void Validate()
    {
        var components = new[]
        {
            FfxivColor.X,
            FfxivColor.Y,
            FfxivColor.Z,
            FfxivColor.W,
        };
        if (components.Any(component => component < 0 || component > 1))
            throw new ArgumentOutOfRangeException(nameof(FfxivColor));
    }
}