Fix wrong face culling once and for all (#1277)

* Viewport swizzle support on NV and clip origin

* Initialize default viewport swizzle state, emulate viewport swizzle on shaders when not supported

* Address PR feedback

1 files changed, 25 insertions, 0 deletions

diff --git a/Ryujinx.Graphics.Gpu/Shader/GpuAccessor.cs b/Ryujinx.Graphics.Gpu/Shader/GpuAccessor.cs
index 76b06ea5..2774b7d1 100644
--- a/Ryujinx.Graphics.Gpu/Shader/GpuAccessor.cs
+++ b/Ryujinx.Graphics.Gpu/Shader/GpuAccessor.cs
@@ -3,6 +3,7 @@ using Ryujinx.Graphics.GAL;
 using Ryujinx.Graphics.Gpu.Image;
 using Ryujinx.Graphics.Gpu.State;
 using Ryujinx.Graphics.Shader;
+using System;
 
 namespace Ryujinx.Graphics.Gpu.Shader
 {
@@ -188,6 +189,12 @@ namespace Ryujinx.Graphics.Gpu.Shader
         public bool QuerySupportsNonConstantTextureOffset() => _context.Capabilities.SupportsNonConstantTextureOffset;
 
         /// <summary>
+        /// Queries host GPU viewport swizzle support.
+        /// </summary>
+        /// <returns>True if the GPU and driver supports viewport swizzle, false otherwise</returns>
+        public bool QuerySupportsViewportSwizzle() => _context.Capabilities.SupportsViewportSwizzle;
+
+        /// <summary>
         /// Queries texture format information, for shaders using image load or store.
         /// </summary>
         /// <remarks>
@@ -250,6 +257,24 @@ namespace Ryujinx.Graphics.Gpu.Shader
             };
         }
 
+        public int QueryViewportSwizzle(int component)
+        {
+            YControl yControl = _state.Get<YControl>(MethodOffset.YControl);
+
+            bool flipY = yControl.HasFlag(YControl.NegateY) ^ !yControl.HasFlag(YControl.TriangleRastFlip);
+
+            ViewportTransform transform = _state.Get<ViewportTransform>(MethodOffset.ViewportTransform, 0);
+
+            return component switch
+            {
+                0 => (int)(transform.UnpackSwizzleX() ^ (transform.ScaleX < 0 ? ViewportSwizzle.NegativeFlag : 0)),
+                1 => (int)(transform.UnpackSwizzleY() ^ (transform.ScaleY < 0 ? ViewportSwizzle.NegativeFlag : 0) ^ (flipY ? ViewportSwizzle.NegativeFlag : 0)),
+                2 => (int)(transform.UnpackSwizzleZ() ^ (transform.ScaleZ < 0 ? ViewportSwizzle.NegativeFlag : 0)),
+                3 => (int)transform.UnpackSwizzleW(),
+                _ => throw new ArgumentOutOfRangeException(nameof(component))
+            };
+        }
+
         /// <summary>
         /// Gets the texture descriptor for a given texture on the pool.
         /// </summary>