Geometry shader emulation for macOS (#5551)

* Implement vertex and geometry shader conversion to compute

* Call InitializeReservedCounts for compute too

* PR feedback

* Set clip distance mask for geometry and tessellation shaders too

* Transform feedback emulation only for vertex

src/Ryujinx.Graphics.Gpu/Engine/Threed/ComputeDraw/VtgAsCompute.cs

@@ -0,0 +1,96 @@
+using Ryujinx.Graphics.GAL;
+using Ryujinx.Graphics.Gpu.Shader;
+using System;
+
+namespace Ryujinx.Graphics.Gpu.Engine.Threed.ComputeDraw
+{
+    /// <summary>
+    /// Vertex, tessellation and geometry as compute shader draw manager.
+    /// </summary>
+    class VtgAsCompute : IDisposable
+    {
+        private readonly GpuContext _context;
+        private readonly GpuChannel _channel;
+        private readonly DeviceStateWithShadow<ThreedClassState> _state;
+        private readonly VtgAsComputeContext _vacContext;
+
+        /// <summary>
+        /// Creates a new instance of the vertex, tessellation and geometry as compute shader draw manager.
+        /// </summary>
+        /// <param name="context">GPU context</param>
+        /// <param name="channel">GPU channel</param>
+        /// <param name="state">3D engine state</param>
+        public VtgAsCompute(GpuContext context, GpuChannel channel, DeviceStateWithShadow<ThreedClassState> state)
+        {
+            _context = context;
+            _channel = channel;
+            _state = state;
+            _vacContext = new(context);
+        }
+
+        /// <summary>
+        /// Emulates the pre-rasterization stages of a draw operation using a compute shader.
+        /// </summary>
+        /// <param name="engine">3D engine</param>
+        /// <param name="vertexAsCompute">Vertex shader converted to compute</param>
+        /// <param name="geometryAsCompute">Optional geometry shader converted to compute</param>
+        /// <param name="vertexPassthroughProgram">Fragment shader with a vertex passthrough shader to feed the compute output into the fragment stage</param>
+        /// <param name="topology">Primitive topology of the draw</param>
+        /// <param name="count">Index or vertex count of the draw</param>
+        /// <param name="instanceCount">Instance count</param>
+        /// <param name="firstIndex">First index on the index buffer, for indexed draws</param>
+        /// <param name="firstVertex">First vertex on the vertex buffer</param>
+        /// <param name="firstInstance">First instance</param>
+        /// <param name="indexed">Whether the draw is indexed</param>
+        public void DrawAsCompute(
+            ThreedClass engine,
+            ShaderAsCompute vertexAsCompute,
+            ShaderAsCompute geometryAsCompute,
+            IProgram vertexPassthroughProgram,
+            PrimitiveTopology topology,
+            int count,
+            int instanceCount,
+            int firstIndex,
+            int firstVertex,
+            int firstInstance,
+            bool indexed)
+        {
+            VtgAsComputeState state = new(
+                _context,
+                _channel,
+                _state,
+                _vacContext,
+                engine,
+                vertexAsCompute,
+                geometryAsCompute,
+                vertexPassthroughProgram,
+                topology,
+                count,
+                instanceCount,
+                firstIndex,
+                firstVertex,
+                firstInstance,
+                indexed);
+
+            state.RunVertex();
+            state.RunGeometry();
+            state.RunFragment();
+
+            _vacContext.FreeBuffers();
+        }
+
+        protected virtual void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                _vacContext.Dispose();
+            }
+        }
+
+        public void Dispose()
+        {
+            Dispose(true);
+            GC.SuppressFinalize(this);
+        }
+    }
+}