using Ryujinx.Common.Logging;
using Ryujinx.Graphics.GAL;
using Ryujinx.Graphics.Gpu.Image;
using Ryujinx.Graphics.Gpu.Memory;
using Ryujinx.Graphics.Gpu.Shader;
using Ryujinx.Graphics.Gpu.State;
using Ryujinx.Graphics.Shader;
using System;
using System.Runtime.InteropServices;

namespace Ryujinx.Graphics.Gpu.Engine
{
    using Texture = Image.Texture;

    /// <summary>
    /// GPU method implementations.
    /// </summary>
    partial class Methods
    {
        private readonly GpuContext _context;
        private readonly ShaderProgramInfo[] _currentProgramInfo;

        /// <summary>
        /// In-memory shader cache.
        /// </summary>
        public ShaderCache ShaderCache { get; }

        /// <summary>
        /// GPU buffer manager.
        /// </summary>
        public BufferManager BufferManager { get; }

        /// <summary>
        /// GPU texture manager.
        /// </summary>
        public TextureManager TextureManager { get; }

        private bool _isAnyVbInstanced;
        private bool _vsUsesInstanceId;

        /// <summary>
        /// Creates a new instance of the GPU methods class.
        /// </summary>
        /// <param name="context">GPU context</param>
        public Methods(GpuContext context)
        {
            _context = context;

            ShaderCache = new ShaderCache(_context);

            _currentProgramInfo = new ShaderProgramInfo[Constants.ShaderStages];

            BufferManager  = new BufferManager(context);
            TextureManager = new TextureManager(context);

            context.MemoryManager.MemoryUnmapped += _counterCache.MemoryUnmappedHandler;
        }

        /// <summary>
        /// Register callback for GPU method calls that triggers an action on the GPU.
        /// </summary>
        /// <param name="state">GPU state where the triggers will be registered</param>
        public void RegisterCallbacks(GpuState state)
        {
            state.RegisterCallback(MethodOffset.LaunchDma,      LaunchDma);
            state.RegisterCallback(MethodOffset.LoadInlineData, LoadInlineData);

            state.RegisterCallback(MethodOffset.Dispatch, Dispatch);

            state.RegisterCallback(MethodOffset.SyncpointAction, IncrementSyncpoint);

            state.RegisterCallback(MethodOffset.CopyBuffer,  CopyBuffer);
            state.RegisterCallback(MethodOffset.CopyTexture, CopyTexture);

            state.RegisterCallback(MethodOffset.TextureBarrier,      TextureBarrier);
            state.RegisterCallback(MethodOffset.InvalidateTextures,  InvalidateTextures);
            state.RegisterCallback(MethodOffset.TextureBarrierTiled, TextureBarrierTiled);

            state.RegisterCallback(MethodOffset.ResetCounter, ResetCounter);

            state.RegisterCallback(MethodOffset.DrawEnd,   DrawEnd);
            state.RegisterCallback(MethodOffset.DrawBegin, DrawBegin);

            state.RegisterCallback(MethodOffset.IndexBufferCount, SetIndexBufferCount);

            state.RegisterCallback(MethodOffset.Clear, Clear);

            state.RegisterCallback(MethodOffset.Report, Report);

            state.RegisterCallback(MethodOffset.FirmwareCall4, FirmwareCall4);

            state.RegisterCallback(MethodOffset.UniformBufferUpdateData, 16, UniformBufferUpdate);

            state.RegisterCallback(MethodOffset.UniformBufferBindVertex,         UniformBufferBindVertex);
            state.RegisterCallback(MethodOffset.UniformBufferBindTessControl,    UniformBufferBindTessControl);
            state.RegisterCallback(MethodOffset.UniformBufferBindTessEvaluation, UniformBufferBindTessEvaluation);
            state.RegisterCallback(MethodOffset.UniformBufferBindGeometry,       UniformBufferBindGeometry);
            state.RegisterCallback(MethodOffset.UniformBufferBindFragment,       UniformBufferBindFragment);
        }

        /// <summary>
        /// Register callback for Fifo method calls that triggers an action on the GPFIFO.
        /// </summary>
        /// <param name="state">GPU state where the triggers will be registered</param>
        public void RegisterCallbacksForFifo(GpuState state)
        {
            state.RegisterCallback(MethodOffset.FenceAction,            FenceAction);
            state.RegisterCallback(MethodOffset.WaitForIdle,            WaitForIdle);
            state.RegisterCallback(MethodOffset.SendMacroCodeData,      SendMacroCodeData);
            state.RegisterCallback(MethodOffset.BindMacro,              BindMacro);
            state.RegisterCallback(MethodOffset.SetMmeShadowRamControl, SetMmeShadowRamControl);
        }

        /// <summary>
        /// Updates host state based on the current guest GPU state.
        /// </summary>
        /// <param name="state">Guest GPU state</param>
        private void UpdateState(GpuState state)
        {
            // Shaders must be the first one to be updated if modified, because
            // some of the other state depends on information from the currently
            // bound shaders.
            if (state.QueryModified(MethodOffset.ShaderBaseAddress, MethodOffset.ShaderState))
            {
                UpdateShaderState(state);
            }

            if (state.QueryModified(MethodOffset.RasterizeEnable))
            {
                UpdateRasterizerState(state);
            }

            if (state.QueryModified(MethodOffset.RtColorState,
                                    MethodOffset.RtDepthStencilState,
                                    MethodOffset.RtControl,
                                    MethodOffset.RtDepthStencilSize,
                                    MethodOffset.RtDepthStencilEnable))
            {
                UpdateRenderTargetState(state, useControl: true);
            }

            if (state.QueryModified(MethodOffset.ScissorState))
            {
                UpdateScissorState(state);
            }

            if (state.QueryModified(MethodOffset.ViewVolumeClipControl))
            {
                UpdateDepthClampState(state);
            }

            if (state.QueryModified(MethodOffset.DepthTestEnable,
                                    MethodOffset.DepthWriteEnable,
                                    MethodOffset.DepthTestFunc))
            {
                UpdateDepthTestState(state);
            }

            if (state.QueryModified(MethodOffset.DepthMode,
                                    MethodOffset.ViewportTransform,
                                    MethodOffset.ViewportExtents))
            {
                UpdateViewportTransform(state);
            }

            if (state.QueryModified(MethodOffset.DepthBiasState,
                                    MethodOffset.DepthBiasFactor,
                                    MethodOffset.DepthBiasUnits,
                                    MethodOffset.DepthBiasClamp))
            {
                UpdateDepthBiasState(state);
            }

            if (state.QueryModified(MethodOffset.StencilBackMasks,
                                    MethodOffset.StencilTestState,
                                    MethodOffset.StencilBackTestState))
            {
                UpdateStencilTestState(state);
            }

            // Pools.
            if (state.QueryModified(MethodOffset.SamplerPoolState, MethodOffset.SamplerIndex))
            {
                UpdateSamplerPoolState(state);
            }

            if (state.QueryModified(MethodOffset.TexturePoolState))
            {
                UpdateTexturePoolState(state);
            }

            // Input assembler state.
            if (state.QueryModified(MethodOffset.VertexAttribState))
            {
                UpdateVertexAttribState(state);
            }

            if (state.QueryModified(MethodOffset.PointSize))
            {
                UpdatePointSizeState(state);
            }

            if (state.QueryModified(MethodOffset.PrimitiveRestartState))
            {
                UpdatePrimitiveRestartState(state);
            }

            if (state.QueryModified(MethodOffset.IndexBufferState))
            {
                UpdateIndexBufferState(state);
            }

            if (state.QueryModified(MethodOffset.VertexBufferDrawState,
                                    MethodOffset.VertexBufferInstanced,
                                    MethodOffset.VertexBufferState,
                                    MethodOffset.VertexBufferEndAddress))
            {
                UpdateVertexBufferState(state);
            }

            if (state.QueryModified(MethodOffset.FaceState))
            {
                UpdateFaceState(state);
            }

            if (state.QueryModified(MethodOffset.RtColorMaskShared, MethodOffset.RtColorMask))
            {
                UpdateRtColorMask(state);
            }

            if (state.QueryModified(MethodOffset.BlendIndependent,
                                    MethodOffset.BlendStateCommon,
                                    MethodOffset.BlendEnableCommon,
                                    MethodOffset.BlendEnable,
                                    MethodOffset.BlendState))
            {
                UpdateBlendState(state);
            }

            CommitBindings();
        }

        /// <summary>
        /// Updates Rasterizer primitive discard state based on guest gpu state.
        /// </summary>
        /// <param name="state">Current GPU state</param>
        private void UpdateRasterizerState(GpuState state)
        {
            Boolean32 enable = state.Get<Boolean32>(MethodOffset.RasterizeEnable);
            _context.Renderer.Pipeline.SetRasterizerDiscard(!enable);
        }

        /// <summary>
        /// Ensures that the bindings are visible to the host GPU.
        /// Note: this actually performs the binding using the host graphics API.
        /// </summary>
        private void CommitBindings()
        {
            UpdateStorageBuffers();

            BufferManager.CommitBindings();
            TextureManager.CommitGraphicsBindings();
        }

        /// <summary>
        /// Updates storage buffer bindings.
        /// </summary>
        private void UpdateStorageBuffers()
        {
            for (int stage = 0; stage < _currentProgramInfo.Length; stage++)
            {
                ShaderProgramInfo info = _currentProgramInfo[stage];

                if (info == null)
                {
                    continue;
                }

                for (int index = 0; index < info.SBuffers.Count; index++)
                {
                    BufferDescriptor sb = info.SBuffers[index];

                    ulong sbDescAddress = BufferManager.GetGraphicsUniformBufferAddress(stage, 0);

                    int sbDescOffset = 0x110 + stage * 0x100 + sb.Slot * 0x10;

                    sbDescAddress += (ulong)sbDescOffset;

                    ReadOnlySpan<byte> sbDescriptorData = _context.PhysicalMemory.GetSpan(sbDescAddress, 0x10);

                    SbDescriptor sbDescriptor = MemoryMarshal.Cast<byte, SbDescriptor>(sbDescriptorData)[0];

                    BufferManager.SetGraphicsStorageBuffer(stage, sb.Slot, sbDescriptor.PackAddress(), (uint)sbDescriptor.Size);
                }
            }
        }

        /// <summary>
        /// Updates render targets (color and depth-stencil buffers) based on current render target state.
        /// </summary>
        /// <param name="state">Current GPU state</param>
        /// <param name="useControl">Use draw buffers information from render target control register</param>
        private void UpdateRenderTargetState(GpuState state, bool useControl)
        {
            var rtControl = state.Get<RtControl>(MethodOffset.RtControl);

            int count = useControl ? rtControl.UnpackCount() : Constants.TotalRenderTargets;

            var msaaMode = state.Get<TextureMsaaMode>(MethodOffset.RtMsaaMode);

            int samplesInX = msaaMode.SamplesInX();
            int samplesInY = msaaMode.SamplesInY();

            for (int index = 0; index < Constants.TotalRenderTargets; index++)
            {
                int rtIndex = useControl ? rtControl.UnpackPermutationIndex(index) : index;

                var colorState = state.Get<RtColorState>(MethodOffset.RtColorState, rtIndex);

                if (index >= count || !IsRtEnabled(colorState))
                {
                    TextureManager.SetRenderTargetColor(index, null);

                    continue;
                }

                Texture color = TextureManager.FindOrCreateTexture(colorState, samplesInX, samplesInY);

                TextureManager.SetRenderTargetColor(index, color);

                if (color != null)
                {
                    color.SignalModified();
                }
            }

            bool dsEnable = state.Get<Boolean32>(MethodOffset.RtDepthStencilEnable);

            Texture depthStencil = null;

            if (dsEnable)
            {
                var dsState = state.Get<RtDepthStencilState>(MethodOffset.RtDepthStencilState);
                var dsSize  = state.Get<Size3D>             (MethodOffset.RtDepthStencilSize);

                depthStencil = TextureManager.FindOrCreateTexture(dsState, dsSize, samplesInX, samplesInY);
            }

            TextureManager.SetRenderTargetDepthStencil(depthStencil);

            if (depthStencil != null)
            {
                depthStencil.SignalModified();
            }
        }

        /// <summary>
        /// Checks if a render target color buffer is used.
        /// </summary>
        /// <param name="colorState">Color buffer information</param>
        /// <returns>True if the specified buffer is enabled/used, false otherwise</returns>
        private static bool IsRtEnabled(RtColorState colorState)
        {
            // Colors are disabled by writing 0 to the format.
            return colorState.Format != 0 && colorState.WidthOrStride != 0;
        }

        /// <summary>
        /// Updates host scissor test state based on current GPU state.
        /// </summary>
        /// <param name="state">Current GPU state</param>
        private void UpdateScissorState(GpuState state)
        {
            for (int index = 0; index < Constants.TotalViewports; index++)
            {
                ScissorState scissor = state.Get<ScissorState>(MethodOffset.ScissorState, index);

                bool enable = scissor.Enable && (scissor.X1 != 0 || scissor.Y1 != 0 || scissor.X2 != 0xffff || scissor.Y2 != 0xffff);

                _context.Renderer.Pipeline.SetScissorEnable(index, enable);

                if (enable)
                {
                    _context.Renderer.Pipeline.SetScissor(index, scissor.X1, scissor.Y1, scissor.X2 - scissor.X1, scissor.Y2 - scissor.Y1);
                }
            }
        }

        /// <summary>
        /// Updates host depth clamp state based on current GPU state.
        /// </summary>
        /// <param name="state">Current GPU state</param>
        private void UpdateDepthClampState(GpuState state)
        {
            ViewVolumeClipControl clip = state.Get<ViewVolumeClipControl>(MethodOffset.ViewVolumeClipControl);
            _context.Renderer.Pipeline.SetDepthClamp((clip & ViewVolumeClipControl.DepthClampNear) != 0,
                                                     (clip & ViewVolumeClipControl.DepthClampFar) != 0);
        }

        /// <summary>
        /// Updates host depth test state based on current GPU state.
        /// </summary>
        /// <param name="state">Current GPU state</param>
        private void UpdateDepthTestState(GpuState state)
        {
            _context.Renderer.Pipeline.SetDepthTest(new DepthTestDescriptor(
                state.Get<Boolean32>(MethodOffset.DepthTestEnable),
                state.Get<Boolean32>(MethodOffset.DepthWriteEnable),
                state.Get<CompareOp>(MethodOffset.DepthTestFunc)));
        }

        /// <summary>
        /// Updates host viewport transform and clipping state based on current GPU state.
        /// </summary>
        /// <param name="state">Current GPU state</param>
        private void UpdateViewportTransform(GpuState state)
        {
            DepthMode depthMode = state.Get<DepthMode>(MethodOffset.DepthMode);

            _context.Renderer.Pipeline.SetDepthMode(depthMode);

            bool flipY = (state.Get<YControl>(MethodOffset.YControl) & YControl.NegateY) != 0;
            float yFlip = flipY ? -1 : 1;

            Viewport[] viewports = new Viewport[Constants.TotalViewports];

            for (int index = 0; index < Constants.TotalViewports; index++)
            {
                var transform = state.Get<ViewportTransform>(MethodOffset.ViewportTransform, index);
                var extents   = state.Get<ViewportExtents>  (MethodOffset.ViewportExtents,   index);

                float x = transform.TranslateX - MathF.Abs(transform.ScaleX);
                float y = transform.TranslateY - MathF.Abs(transform.ScaleY);

                float width  = transform.ScaleX * 2;
                float height = transform.ScaleY * 2 * yFlip;

                RectangleF region = new RectangleF(x, y, width, height);

                viewports[index] = new Viewport(
                    region,
                    transform.UnpackSwizzleX(),
                    transform.UnpackSwizzleY(),
                    transform.UnpackSwizzleZ(),
                    transform.UnpackSwizzleW(),
                    extents.DepthNear,
                    extents.DepthFar);
            }

            _context.Renderer.Pipeline.SetViewports(0, viewports);
        }

        /// <summary>
        /// Updates host depth bias (also called polygon offset) state based on current GPU state.
        /// </summary>
        /// <param name="state">Current GPU state</param>
        private void UpdateDepthBiasState(GpuState state)
        {
            var depthBias = state.Get<DepthBiasState>(MethodOffset.DepthBiasState);

            float factor = state.Get<float>(MethodOffset.DepthBiasFactor);
            float units  = state.Get<float>(MethodOffset.DepthBiasUnits);
            float clamp  = state.Get<float>(MethodOffset.DepthBiasClamp);

            PolygonModeMask enables;

            enables  = (depthBias.PointEnable ? PolygonModeMask.Point : 0);
            enables |= (depthBias.LineEnable  ? PolygonModeMask.Line  : 0);
            enables |= (depthBias.FillEnable  ? PolygonModeMask.Fill  : 0);

            _context.Renderer.Pipeline.SetDepthBias(enables, factor, units, clamp);
        }

        /// <summary>
        /// Updates host stencil test state based on current GPU state.
        /// </summary>
        /// <param name="state">Current GPU state</param>
        private void UpdateStencilTestState(GpuState state)
        {
            var backMasks = state.Get<StencilBackMasks>    (MethodOffset.StencilBackMasks);
            var test      = state.Get<StencilTestState>    (MethodOffset.StencilTestState);
            var backTest  = state.Get<StencilBackTestState>(MethodOffset.StencilBackTestState);

            CompareOp backFunc;
            StencilOp backSFail;
            StencilOp backDpPass;
            StencilOp backDpFail;
            int       backFuncRef;
            int       backFuncMask;
            int       backMask;

            if (backTest.TwoSided)
            {
                backFunc     = backTest.BackFunc;
                backSFail    = backTest.BackSFail;
                backDpPass   = backTest.BackDpPass;
                backDpFail   = backTest.BackDpFail;
                backFuncRef  = backMasks.FuncRef;
                backFuncMask = backMasks.FuncMask;
                backMask     = backMasks.Mask;
            }
            else
            {
                backFunc     = test.FrontFunc;
                backSFail    = test.FrontSFail;
                backDpPass   = test.FrontDpPass;
                backDpFail   = test.FrontDpFail;
                backFuncRef  = test.FrontFuncRef;
                backFuncMask = test.FrontFuncMask;
                backMask     = test.FrontMask;
            }

            _context.Renderer.Pipeline.SetStencilTest(new StencilTestDescriptor(
                test.Enable,
                test.FrontFunc,
                test.FrontSFail,
                test.FrontDpPass,
                test.FrontDpFail,
                test.FrontFuncRef,
                test.FrontFuncMask,
                test.FrontMask,
                backFunc,
                backSFail,
                backDpPass,
                backDpFail,
                backFuncRef,
                backFuncMask,
                backMask));
        }

        /// <summary>
        /// Updates current sampler pool address and size based on guest GPU state.
        /// </summary>
        /// <param name="state">Current GPU state</param>
        private void UpdateSamplerPoolState(GpuState state)
        {
            var texturePool = state.Get<PoolState>(MethodOffset.TexturePoolState);
            var samplerPool = state.Get<PoolState>(MethodOffset.SamplerPoolState);

            var samplerIndex = state.Get<SamplerIndex>(MethodOffset.SamplerIndex);

            int maximumId = samplerIndex == SamplerIndex.ViaHeaderIndex
                ? texturePool.MaximumId
                : samplerPool.MaximumId;

            TextureManager.SetGraphicsSamplerPool(samplerPool.Address.Pack(), maximumId, samplerIndex);
        }

        /// <summary>
        /// Updates current texture pool address and size based on guest GPU state.
        /// </summary>
        /// <param name="state">Current GPU state</param>
        private void UpdateTexturePoolState(GpuState state)
        {
            var texturePool = state.Get<PoolState>(MethodOffset.TexturePoolState);

            TextureManager.SetGraphicsTexturePool(texturePool.Address.Pack(), texturePool.MaximumId);

            TextureManager.SetGraphicsTextureBufferIndex(state.Get<int>(MethodOffset.TextureBufferIndex));
        }

        /// <summary>
        /// Updates host vertex attributes based on guest GPU state.
        /// </summary>
        /// <param name="state">Current GPU state</param>
        private void UpdateVertexAttribState(GpuState state)
        {
            VertexAttribDescriptor[] vertexAttribs = new VertexAttribDescriptor[16];

            for (int index = 0; index < 16; index++)
            {
                var vertexAttrib = state.Get<VertexAttribState>(MethodOffset.VertexAttribState, index);

                if (!FormatTable.TryGetAttribFormat(vertexAttrib.UnpackFormat(), out Format format))
                {
                    Logger.PrintDebug(LogClass.Gpu, $"Invalid attribute format 0x{vertexAttrib.UnpackFormat():X}.");

                    format = Format.R32G32B32A32Float;
                }

                vertexAttribs[index] = new VertexAttribDescriptor(
                    vertexAttrib.UnpackBufferIndex(),
                    vertexAttrib.UnpackOffset(),
                    vertexAttrib.UnpackIsConstant(),
                    format);
            }

            _context.Renderer.Pipeline.SetVertexAttribs(vertexAttribs);
        }

        /// <summary>
        /// Updates host point size based on guest GPU state.
        /// </summary>
        /// <param name="state">Current GPU state</param>
        private void UpdatePointSizeState(GpuState state)
        {
            float size = state.Get<float>(MethodOffset.PointSize);

            _context.Renderer.Pipeline.SetPointSize(size);
        }

        /// <summary>
        /// Updates host primitive restart based on guest GPU state.
        /// </summary>
        /// <param name="state">Current GPU state</param>
        private void UpdatePrimitiveRestartState(GpuState state)
        {
            PrimitiveRestartState primitiveRestart = state.Get<PrimitiveRestartState>(MethodOffset.PrimitiveRestartState);

            _context.Renderer.Pipeline.SetPrimitiveRestart(
                primitiveRestart.Enable,
                primitiveRestart.Index);
        }

        /// <summary>
        /// Updates host index buffer binding based on guest GPU state.
        /// </summary>
        /// <param name="state">Current GPU state</param>
        private void UpdateIndexBufferState(GpuState state)
        {
            var indexBuffer = state.Get<IndexBufferState>(MethodOffset.IndexBufferState);

            _firstIndex = indexBuffer.First;
            _indexCount = indexBuffer.Count;

            if (_indexCount == 0)
            {
                return;
            }

            ulong gpuVa = indexBuffer.Address.Pack();

            // Do not use the end address to calculate the size, because
            // the result may be much larger than the real size of the index buffer.
            ulong size = (ulong)(_firstIndex + _indexCount);

            switch (indexBuffer.Type)
            {
                case IndexType.UShort: size *= 2; break;
                case IndexType.UInt:   size *= 4; break;
            }

            BufferManager.SetIndexBuffer(gpuVa, size, indexBuffer.Type);

            // The index buffer affects the vertex buffer size calculation, we
            // need to ensure that they are updated.
            UpdateVertexBufferState(state);
        }

        /// <summary>
        /// Updates host vertex buffer bindings based on guest GPU state.
        /// </summary>
        /// <param name="state">Current GPU state</param>
        private void UpdateVertexBufferState(GpuState state)
        {
            _isAnyVbInstanced = false;

            for (int index = 0; index < 16; index++)
            {
                var vertexBuffer = state.Get<VertexBufferState>(MethodOffset.VertexBufferState, index);

                if (!vertexBuffer.UnpackEnable())
                {
                    BufferManager.SetVertexBuffer(index, 0, 0, 0, 0);

                    continue;
                }

                GpuVa endAddress = state.Get<GpuVa>(MethodOffset.VertexBufferEndAddress, index);

                ulong address = vertexBuffer.Address.Pack();

                int stride = vertexBuffer.UnpackStride();

                bool instanced = state.Get<Boolean32>(MethodOffset.VertexBufferInstanced + index);

                int divisor = instanced ? vertexBuffer.Divisor : 0;

                _isAnyVbInstanced |= divisor != 0;

                ulong size;

                if (_drawIndexed || stride == 0 || instanced)
                {
                    // This size may be (much) larger than the real vertex buffer size.
                    // Avoid calculating it this way, unless we don't have any other option.
                    size = endAddress.Pack() - address + 1;
                }
                else
                {
                    // For non-indexed draws, we can guess the size from the vertex count
                    // and stride.
                    int firstInstance = state.Get<int>(MethodOffset.FirstInstance);

                    var drawState = state.Get<VertexBufferDrawState>(MethodOffset.VertexBufferDrawState);

                    size = (ulong)((firstInstance + drawState.First + drawState.Count) * stride);
                }

                BufferManager.SetVertexBuffer(index, address, size, stride, divisor);
            }
        }

        /// <summary>
        /// Updates host face culling and orientation based on guest GPU state.
        /// </summary>
        /// <param name="state">Current GPU state</param>
        private void UpdateFaceState(GpuState state)
        {
            var face = state.Get<FaceState>(MethodOffset.FaceState);

            _context.Renderer.Pipeline.SetFaceCulling(face.CullEnable, face.CullFace);

            _context.Renderer.Pipeline.SetFrontFace(face.FrontFace);
        }

        /// <summary>
        /// Updates host render target color masks, based on guest GPU state.
        /// This defines which color channels are written to each color buffer.
        /// </summary>
        /// <param name="state">Current GPU state</param>
        private void UpdateRtColorMask(GpuState state)
        {
            bool rtColorMaskShared = state.Get<Boolean32>(MethodOffset.RtColorMaskShared);

            uint[] componentMasks = new uint[Constants.TotalRenderTargets];

            for (int index = 0; index < Constants.TotalRenderTargets; index++)
            {
                var colorMask = state.Get<RtColorMask>(MethodOffset.RtColorMask, rtColorMaskShared ? 0 : index);

                uint componentMask;

                componentMask  = (colorMask.UnpackRed()   ? 1u : 0u);
                componentMask |= (colorMask.UnpackGreen() ? 2u : 0u);
                componentMask |= (colorMask.UnpackBlue()  ? 4u : 0u);
                componentMask |= (colorMask.UnpackAlpha() ? 8u : 0u);

                componentMasks[index] = componentMask;
            }

            _context.Renderer.Pipeline.SetRenderTargetColorMasks(componentMasks);
        }

        /// <summary>
        /// Updates host render target color buffer blending state, based on guest state.
        /// </summary>
        /// <param name="state">Current GPU state</param>
        private void UpdateBlendState(GpuState state)
        {
            bool blendIndependent = state.Get<Boolean32>(MethodOffset.BlendIndependent);

            for (int index = 0; index < 8; index++)
            {
                BlendDescriptor descriptor;

                if (blendIndependent)
                {
                    bool enable = state.Get<Boolean32> (MethodOffset.BlendEnable, index);
                    var  blend  = state.Get<BlendState>(MethodOffset.BlendState,  index);

                    descriptor = new BlendDescriptor(
                        enable,
                        blend.ColorOp,
                        blend.ColorSrcFactor,
                        blend.ColorDstFactor,
                        blend.AlphaOp,
                        blend.AlphaSrcFactor,
                        blend.AlphaDstFactor);
                }
                else
                {
                    bool enable = state.Get<Boolean32>       (MethodOffset.BlendEnable, 0);
                    var  blend  = state.Get<BlendStateCommon>(MethodOffset.BlendStateCommon);

                    descriptor = new BlendDescriptor(
                        enable,
                        blend.ColorOp,
                        blend.ColorSrcFactor,
                        blend.ColorDstFactor,
                        blend.AlphaOp,
                        blend.AlphaSrcFactor,
                        blend.AlphaDstFactor);
                }

                _context.Renderer.Pipeline.SetBlendState(index, descriptor);
            }
        }

        /// <summary>
        /// Storage buffer address and size information.
        /// </summary>
        private struct SbDescriptor
        {
#pragma warning disable CS0649
            public uint AddressLow;
            public uint AddressHigh;
            public int  Size;
            public int  Padding;
#pragma warning restore CS0649

            public ulong PackAddress()
            {
                return AddressLow | ((ulong)AddressHigh << 32);
            }
        }

        /// <summary>
        /// Updates host shaders based on the guest GPU state.
        /// </summary>
        /// <param name="state">Current GPU state</param>
        private void UpdateShaderState(GpuState state)
        {
            ShaderAddresses addresses = new ShaderAddresses();

            Span<ShaderAddresses> addressesSpan = MemoryMarshal.CreateSpan(ref addresses, 1);

            Span<ulong> addressesArray = MemoryMarshal.Cast<ShaderAddresses, ulong>(addressesSpan);

            ulong baseAddress = state.Get<GpuVa>(MethodOffset.ShaderBaseAddress).Pack();

            for (int index = 0; index < 6; index++)
            {
                var shader = state.Get<ShaderState>(MethodOffset.ShaderState, index);

                if (!shader.UnpackEnable() && index != 1)
                {
                    continue;
                }

                addressesArray[index] = baseAddress + shader.Offset;
            }

            GraphicsShader gs = ShaderCache.GetGraphicsShader(state, addresses);

            _vsUsesInstanceId = gs.Shaders[0]?.Program.Info.UsesInstanceId ?? false;

            for (int stage = 0; stage < Constants.ShaderStages; stage++)
            {
                ShaderProgramInfo info = gs.Shaders[stage]?.Program.Info;

                _currentProgramInfo[stage] = info;

                if (info == null)
                {
                    continue;
                }

                var textureBindings = new TextureBindingInfo[info.Textures.Count];

                for (int index = 0; index < info.Textures.Count; index++)
                {
                    var descriptor = info.Textures[index];

                    Target target = GetTarget(descriptor.Type);

                    if (descriptor.IsBindless)
                    {
                        textureBindings[index] = new TextureBindingInfo(target, descriptor.CbufSlot, descriptor.CbufOffset);
                    }
                    else
                    {
                        textureBindings[index] = new TextureBindingInfo(target, descriptor.HandleIndex);
                    }
                }

                TextureManager.SetGraphicsTextures(stage, textureBindings);

                var imageBindings = new TextureBindingInfo[info.Images.Count];

                for (int index = 0; index < info.Images.Count; index++)
                {
                    var descriptor = info.Images[index];

                    Target target = GetTarget(descriptor.Type);

                    imageBindings[index] = new TextureBindingInfo(target, descriptor.HandleIndex);
                }

                TextureManager.SetGraphicsImages(stage, imageBindings);

                uint sbEnableMask = 0;
                uint ubEnableMask = 0;

                for (int index = 0; index < info.SBuffers.Count; index++)
                {
                    sbEnableMask |= 1u << info.SBuffers[index].Slot;
                }

                for (int index = 0; index < info.CBuffers.Count; index++)
                {
                    ubEnableMask |= 1u << info.CBuffers[index].Slot;
                }

                BufferManager.SetGraphicsStorageBufferEnableMask(stage, sbEnableMask);
                BufferManager.SetGraphicsUniformBufferEnableMask(stage, ubEnableMask);
            }

            _context.Renderer.Pipeline.SetProgram(gs.HostProgram);
        }

        /// <summary>
        /// Gets texture target from a sampler type.
        /// </summary>
        /// <param name="type">Sampler type</param>
        /// <returns>Texture target value</returns>
        private static Target GetTarget(SamplerType type)
        {
            type &= ~(SamplerType.Indexed | SamplerType.Shadow);

            switch (type)
            {
                case SamplerType.Texture1D:
                    return Target.Texture1D;

                case SamplerType.TextureBuffer:
                    return Target.TextureBuffer;

                case SamplerType.Texture1D | SamplerType.Array:
                    return Target.Texture1DArray;

                case SamplerType.Texture2D:
                    return Target.Texture2D;

                case SamplerType.Texture2D | SamplerType.Array:
                    return Target.Texture2DArray;

                case SamplerType.Texture2D | SamplerType.Multisample:
                    return Target.Texture2DMultisample;

                case SamplerType.Texture2D | SamplerType.Multisample | SamplerType.Array:
                    return Target.Texture2DMultisampleArray;

                case SamplerType.Texture3D:
                    return Target.Texture3D;

                case SamplerType.TextureCube:
                    return Target.Cubemap;

                case SamplerType.TextureCube | SamplerType.Array:
                    return Target.CubemapArray;
            }

            Logger.PrintWarning(LogClass.Gpu, $"Invalid sampler type \"{type}\".");

            return Target.Texture2D;
        }

        /// <summary>
        /// Issues a texture barrier.
        /// This waits until previous texture writes from the GPU to finish, before
        /// performing new operations with said textures.
        /// </summary>
        /// <param name="state">Current GPU state (unused)</param>
        /// <param name="argument">Method call argument (unused)</param>
        private void TextureBarrier(GpuState state, int argument)
        {
            _context.Renderer.Pipeline.TextureBarrier();
        }

        /// <summary>
        /// Invalidates all modified textures on the cache.
        /// </summary>
        /// <param name="state">Current GPU state (unused)</param>
        /// <param name="argument">Method call argument (unused)</param>
        private void InvalidateTextures(GpuState state, int argument)
        {
            TextureManager.Flush();
        }

        /// <summary>
        /// Issues a texture barrier.
        /// This waits until previous texture writes from the GPU to finish, before
        /// performing new operations with said textures.
        /// This performs a per-tile wait, it is only valid if both the previous write
        /// and current access has the same access patterns.
        /// This may be faster than the regular barrier on tile-based rasterizers.
        /// </summary>
        /// <param name="state">Current GPU state (unused)</param>
        /// <param name="argument">Method call argument (unused)</param>
        private void TextureBarrierTiled(GpuState state, int argument)
        {
            _context.Renderer.Pipeline.TextureBarrierTiled();
        }
    }
}