Ryujinx/src/Ryujinx.Graphics.Metal/HelperShader.cs

using Ryujinx.Common;
using Ryujinx.Graphics.GAL;
using Ryujinx.Graphics.Shader;
using Ryujinx.Graphics.Shader.Translation;
using SharpMetal.Metal;
using System;
using System.Collections.Generic;
using System.Runtime.Versioning;

namespace Ryujinx.Graphics.Metal
{
    [SupportedOSPlatform("macos")]
    class HelperShader : IDisposable
    {
        private const string ShadersSourcePath = "/Ryujinx.Graphics.Metal/Shaders";
        private readonly Pipeline _pipeline;
        private MTLDevice _device;

        private readonly ISampler _samplerLinear;
        private readonly ISampler _samplerNearest;
        private readonly IProgram _programColorBlit;
        private readonly List<IProgram> _programsColorClear = new();
        private readonly IProgram _programDepthStencilClear;

        public HelperShader(MTLDevice device, Pipeline pipeline)
        {
            _device = device;
            _pipeline = pipeline;

            _samplerNearest = new Sampler(_device, SamplerCreateInfo.Create(MinFilter.Nearest, MagFilter.Nearest));
            _samplerLinear = new Sampler(_device, SamplerCreateInfo.Create(MinFilter.Linear, MagFilter.Linear));

            var blitSource = ReadMsl("Blit.metal");
            _programColorBlit = new Program(
            [
                new ShaderSource(blitSource, ShaderStage.Fragment, TargetLanguage.Msl),
                new ShaderSource(blitSource, ShaderStage.Vertex, TargetLanguage.Msl)
            ], device);

            var colorClearSource = ReadMsl("ColorClear.metal");
            for (int i = 0; i < Constants.MaxColorAttachments; i++)
            {
                var crntSource = colorClearSource.Replace("COLOR_ATTACHMENT_INDEX", i.ToString());
                _programsColorClear.Add(new Program(
                [
                    new ShaderSource(crntSource, ShaderStage.Fragment, TargetLanguage.Msl),
                    new ShaderSource(crntSource, ShaderStage.Vertex, TargetLanguage.Msl)
                ], device));
            }

            var depthStencilClearSource = ReadMsl("DepthStencilClear.metal");
            _programDepthStencilClear = new Program(
            [
                new ShaderSource(depthStencilClearSource, ShaderStage.Fragment, TargetLanguage.Msl),
                new ShaderSource(depthStencilClearSource, ShaderStage.Vertex, TargetLanguage.Msl)
            ], device);
        }

        private static string ReadMsl(string fileName)
        {
            return EmbeddedResources.ReadAllText(string.Join('/', ShadersSourcePath, fileName));
        }

        public unsafe void BlitColor(
            ITexture src,
            ITexture dst,
            Extents2D srcRegion,
            Extents2D dstRegion,
            bool linearFilter)
        {
            const int RegionBufferSize = 16;

            var sampler = linearFilter ? _samplerLinear : _samplerNearest;

            Span<float> region = stackalloc float[RegionBufferSize / sizeof(float)];

            region[0] = srcRegion.X1 / (float)src.Width;
            region[1] = srcRegion.X2 / (float)src.Width;
            region[2] = srcRegion.Y1 / (float)src.Height;
            region[3] = srcRegion.Y2 / (float)src.Height;

            if (dstRegion.X1 > dstRegion.X2)
            {
                (region[0], region[1]) = (region[1], region[0]);
            }

            if (dstRegion.Y1 > dstRegion.Y2)
            {
                (region[2], region[3]) = (region[3], region[2]);
            }

            var rect = new Rectangle<float>(
                MathF.Min(dstRegion.X1, dstRegion.X2),
                MathF.Min(dstRegion.Y1, dstRegion.Y2),
                MathF.Abs(dstRegion.X2 - dstRegion.X1),
                MathF.Abs(dstRegion.Y2 - dstRegion.Y1));

            Span<Viewport> viewports = stackalloc Viewport[1];

            viewports[0] = new Viewport(
                rect,
                ViewportSwizzle.PositiveX,
                ViewportSwizzle.PositiveY,
                ViewportSwizzle.PositiveZ,
                ViewportSwizzle.PositiveW,
                0f,
                1f);

            int dstWidth = dst.Width;
            int dstHeight = dst.Height;

            // Save current state
            _pipeline.SaveAndResetState();

            _pipeline.SetProgram(_programColorBlit);
            _pipeline.SetViewports(viewports);
            _pipeline.SetScissors(stackalloc Rectangle<int>[] { new Rectangle<int>(0, 0, dstWidth, dstHeight) });
            _pipeline.SetRenderTargets([dst], null);
            _pipeline.SetClearLoadAction(true);
            _pipeline.SetTextureAndSampler(ShaderStage.Fragment, 0, src, sampler);
            _pipeline.SetPrimitiveTopology(PrimitiveTopology.TriangleStrip);

            fixed (float* ptr = region)
            {
                _pipeline.GetOrCreateRenderEncoder().SetVertexBytes((IntPtr)ptr, RegionBufferSize, 0);
            }

            _pipeline.Draw(4, 1, 0, 0);

            // Restore previous state
            _pipeline.RestoreState();
        }

        public unsafe void DrawTexture(
            ITexture src,
            ISampler srcSampler,
            Extents2DF srcRegion,
            Extents2DF dstRegion)
        {
            const int RegionBufferSize = 16;

            Span<float> region = stackalloc float[RegionBufferSize / sizeof(float)];

            region[0] = srcRegion.X1 / src.Width;
            region[1] = srcRegion.X2 / src.Width;
            region[2] = srcRegion.Y1 / src.Height;
            region[3] = srcRegion.Y2 / src.Height;

            if (dstRegion.X1 > dstRegion.X2)
            {
                (region[0], region[1]) = (region[1], region[0]);
            }

            if (dstRegion.Y1 > dstRegion.Y2)
            {
                (region[2], region[3]) = (region[3], region[2]);
            }

            Span<Viewport> viewports = stackalloc Viewport[1];
            Span<Rectangle<int>> scissors = stackalloc Rectangle<int>[1];

            var rect = new Rectangle<float>(
                MathF.Min(dstRegion.X1, dstRegion.X2),
                MathF.Min(dstRegion.Y1, dstRegion.Y2),
                MathF.Abs(dstRegion.X2 - dstRegion.X1),
                MathF.Abs(dstRegion.Y2 - dstRegion.Y1));

            viewports[0] = new Viewport(
                rect,
                ViewportSwizzle.PositiveX,
                ViewportSwizzle.PositiveY,
                ViewportSwizzle.PositiveZ,
                ViewportSwizzle.PositiveW,
                0f,
                1f);

            scissors[0] = new Rectangle<int>(0, 0, 0xFFFF, 0xFFFF);

            // Save current state
            _pipeline.SaveState();

            _pipeline.SetProgram(_programColorBlit);
            _pipeline.SetViewports(viewports);
            _pipeline.SetScissors(scissors);
            _pipeline.SetTextureAndSampler(ShaderStage.Fragment, 0, src, srcSampler);
            _pipeline.SetPrimitiveTopology(PrimitiveTopology.TriangleStrip);
            _pipeline.SetFaceCulling(false, Face.FrontAndBack);
            // For some reason this results in a SIGSEGV
            // _pipeline.SetStencilTest(CreateStencilTestDescriptor(false));
            _pipeline.SetDepthTest(new DepthTestDescriptor(false, false, CompareOp.Always));

            fixed (float* ptr = region)
            {
                _pipeline.GetOrCreateRenderEncoder().SetVertexBytes((IntPtr)ptr, RegionBufferSize, 0);
            }

            _pipeline.Draw(4, 1, 0, 0);

            // Restore previous state
            _pipeline.RestoreState();
        }

        public unsafe void ClearColor(
            int index,
            ReadOnlySpan<float> clearColor,
            uint componentMask,
            int dstWidth,
            int dstHeight)
        {
            const int ClearColorBufferSize = 16;

            // Save current state
            _pipeline.SaveState();

            Span<Viewport> viewports = stackalloc Viewport[1];

            // TODO: Set exact viewport!
            viewports[0] = new Viewport(
                new Rectangle<float>(0, 0, dstWidth, dstHeight),
                ViewportSwizzle.PositiveX,
                ViewportSwizzle.PositiveY,
                ViewportSwizzle.PositiveZ,
                ViewportSwizzle.PositiveW,
                0f,
                1f);

            _pipeline.SetProgram(_programsColorClear[index]);
            _pipeline.SetBlendState(index, new BlendDescriptor(false, new ColorF(0f, 0f, 0f, 1f), BlendOp.Add, BlendFactor.One, BlendFactor.Zero, BlendOp.Add, BlendFactor.One, BlendFactor.Zero));
            _pipeline.SetFaceCulling(false, Face.Front);
            _pipeline.SetDepthTest(new DepthTestDescriptor(false, false, CompareOp.Always));
            _pipeline.SetRenderTargetColorMasks([componentMask]);
            _pipeline.SetPrimitiveTopology(PrimitiveTopology.TriangleStrip);
            _pipeline.SetViewports(viewports);

            fixed (float* ptr = clearColor)
            {
                _pipeline.GetOrCreateRenderEncoder().SetFragmentBytes((IntPtr)ptr, ClearColorBufferSize, 0);
            }

            _pipeline.Draw(4, 1, 0, 0);

            // Restore previous state
            _pipeline.RestoreState();
        }

        public unsafe void ClearDepthStencil(
            float depthValue,
            bool depthMask,
            int stencilValue,
            int stencilMask,
            int dstWidth,
            int dstHeight)
        {
            const int ClearDepthBufferSize = 4;

            IntPtr ptr = new(&depthValue);

            // Save current state
            _pipeline.SaveState();

            Span<Viewport> viewports = stackalloc Viewport[1];

            viewports[0] = new Viewport(
                new Rectangle<float>(0, 0, dstWidth, dstHeight),
                ViewportSwizzle.PositiveX,
                ViewportSwizzle.PositiveY,
                ViewportSwizzle.PositiveZ,
                ViewportSwizzle.PositiveW,
                0f,
                1f);

            _pipeline.SetProgram(_programDepthStencilClear);
            _pipeline.SetFaceCulling(false, Face.Front);
            _pipeline.SetDepthTest(new DepthTestDescriptor(false, false, CompareOp.Always));
            _pipeline.SetPrimitiveTopology(PrimitiveTopology.TriangleStrip);
            _pipeline.SetViewports(viewports);
            _pipeline.SetDepthTest(new DepthTestDescriptor(true, depthMask, CompareOp.Always));
            // _pipeline.SetStencilTest(CreateStencilTestDescriptor(stencilMask != 0, stencilValue, 0xFF, stencilMask));
            _pipeline.GetOrCreateRenderEncoder().SetFragmentBytes(ptr, ClearDepthBufferSize, 0);
            _pipeline.Draw(4, 1, 0, 0);

            // Restore previous state
            _pipeline.RestoreState();
        }

        private static StencilTestDescriptor CreateStencilTestDescriptor(
            bool enabled,
            int refValue = 0,
            int compareMask = 0xff,
            int writeMask = 0xff)
        {
            return new StencilTestDescriptor(
                enabled,
                CompareOp.Always,
                StencilOp.Replace,
                StencilOp.Replace,
                StencilOp.Replace,
                refValue,
                compareMask,
                writeMask,
                CompareOp.Always,
                StencilOp.Replace,
                StencilOp.Replace,
                StencilOp.Replace,
                refValue,
                compareMask,
                writeMask);
        }

        public void Dispose()
        {
            _programColorBlit.Dispose();
            foreach (var programColorClear in _programsColorClear)
            {
                programColorClear.Dispose();
            }
            _programDepthStencilClear.Dispose();
            _pipeline.Dispose();
            _samplerLinear.Dispose();
            _samplerNearest.Dispose();
        }
    }
}