veldrid-cursed

using System.Diagnostics;
using Furball.Vixie.Backends.Shared.Renderers;
using Veldrid;

namespace Furball.Vixie.Backends.Veldrid; 

public class VeldridBufferMapper : BufferMapper {
    private readonly VeldridBackend _backend;
    private          DeviceBuffer   _buffer;

    public unsafe void* Ptr;
    
    public VeldridBufferMapper(VeldridBackend backend, uint byteSize, BufferUsage usage) {
        this._backend = backend;

        Debug.Assert((usage & ~(BufferUsage.IndexBuffer | BufferUsage.VertexBuffer)) == 0, "(usage & ~(BufferUsage.IndexBuffer | BufferUsage.VertexBuffer)) == 0");
        
        BufferDescription desc = new(byteSize, BufferUsage.Dynamic | usage);
        this._buffer = this._backend.ResourceFactory.CreateBuffer(ref desc);

        this.SizeInBytes = byteSize;
    }
    
    public override unsafe void Map() {
        MappedResource map = this._backend.GraphicsDevice.Map(this._buffer, MapMode.Write);

        this.Ptr = (void*)map.Data;
    }
    
    public override void Unmap() {
        this._backend.GraphicsDevice.Unmap(this._buffer);
    }
    
    public override unsafe void* Reserve(nuint byteCount) {
        nuint ptr = (nuint)this.Ptr + this.ReservedBytes;

        //If this reserve will push us over the limit, return nullptr
        if (this.ReservedBytes + byteCount > this.SizeInBytes)
            return null;
        
        this.ReservedBytes += byteCount;

        return (void*)ptr;
    }
    
    protected override void DisposeInternal() {
        this._buffer.Dispose();
    }
}

using System.Diagnostics;
using Furball.Vixie.Backends.Shared.Renderers;
using Veldrid;

namespace Furball.Vixie.Backends.Veldrid; 

public class VeldridBufferMapper : BufferMapper {
    private readonly VeldridBackend _backend;
    private          DeviceBuffer   _buffer;

    public unsafe void* Ptr;
    
    public VeldridBufferMapper(VeldridBackend backend, uint byteSize, BufferUsage usage) {
        this._backend = backend;

        Debug.Assert((usage & ~(BufferUsage.IndexBuffer | BufferUsage.VertexBuffer)) == 0, "(usage & ~(BufferUsage.IndexBuffer | BufferUsage.VertexBuffer)) == 0");
        
        BufferDescription desc = new(byteSize, BufferUsage.Dynamic | usage);
        this._buffer = this._backend.ResourceFactory.CreateBuffer(ref desc);

        this.SizeInBytes = byteSize;
    }
    
    public override unsafe void Map() {
        MappedResource map = this._backend.GraphicsDevice.Map(this._buffer, MapMode.Write);

        this.Ptr = (void*)map.Data;
    }
    
    public override void Unmap() {
        this._backend.GraphicsDevice.Unmap(this._buffer);
    }
    
    public override unsafe void* Reserve(nuint byteCount) {
        nuint ptr = (nuint)this.Ptr + this.ReservedBytes;

        //If this reserve will push us over the limit, return nullptr
        if (this.ReservedBytes + byteCount > this.SizeInBytes)
            return null;
        
        this.ReservedBytes += byteCount;

        return (void*)ptr;
    }
    
    protected override void DisposeInternal() {
        this._buffer.Dispose();
    }
}