Implement DrawTexture functionality (#2747)

* Implement DrawTexture functionality

* Non-NVIDIA support

* Disable some features that should not affect draw texture (slow path)

* Remove space from shader source

* Match 2D engine names

* Fix resolution scale and add missing XML docs

* Disable transform feedback for draw texture fallback

3 files changed, 81 insertions, 1 deletions

diff --git a/Ryujinx.Graphics.Gpu/Engine/Threed/DrawManager.cs b/Ryujinx.Graphics.Gpu/Engine/Threed/DrawManager.cs
index a060c6c9..518e71ad 100644
--- a/Ryujinx.Graphics.Gpu/Engine/Threed/DrawManager.cs
+++ b/Ryujinx.Graphics.Gpu/Engine/Threed/DrawManager.cs
@@ -320,6 +320,65 @@ namespace Ryujinx.Graphics.Gpu.Engine.Threed
         }
 
         /// <summary>
+        /// Performs a texture draw with a source texture and sampler ID, along with source
+        /// and destination coordinates and sizes.
+        /// </summary>
+        /// <param name="engine">3D engine where this method is being called</param>
+        /// <param name="argument">Method call argument</param>
+        public void DrawTexture(ThreedClass engine, int argument)
+        {
+            static float FixedToFloat(int fixedValue)
+            {
+                return fixedValue * (1f / 4096);
+            }
+
+            float dstX0 = FixedToFloat(_state.State.DrawTextureDstX);
+            float dstY0 = FixedToFloat(_state.State.DrawTextureDstY);
+            float dstWidth = FixedToFloat(_state.State.DrawTextureDstWidth);
+            float dstHeight = FixedToFloat(_state.State.DrawTextureDstHeight);
+
+            // TODO: Confirm behaviour on hardware.
+            // When this is active, the origin appears to be on the bottom.
+            if (_state.State.YControl.HasFlag(YControl.NegateY))
+            {
+                dstY0 -= dstHeight;
+            }
+
+            float dstX1 = dstX0 + dstWidth;
+            float dstY1 = dstY0 + dstHeight;
+
+            float srcX0 = FixedToFloat(_state.State.DrawTextureSrcX);
+            float srcY0 = FixedToFloat(_state.State.DrawTextureSrcY);
+            float srcX1 = ((float)_state.State.DrawTextureDuDx / (1UL << 32)) * dstWidth + srcX0;
+            float srcY1 = ((float)_state.State.DrawTextureDvDy / (1UL << 32)) * dstHeight + srcY0;
+
+            engine.UpdateState();
+
+            int textureId = _state.State.DrawTextureTextureId;
+            int samplerId = _state.State.DrawTextureSamplerId;
+
+            (var texture, var sampler) = _channel.TextureManager.GetGraphicsTextureAndSampler(textureId, samplerId);
+
+            srcX0 *= texture.ScaleFactor;
+            srcY0 *= texture.ScaleFactor;
+            srcX1 *= texture.ScaleFactor;
+            srcY1 *= texture.ScaleFactor;
+
+            float dstScale = _channel.TextureManager.RenderTargetScale;
+
+            dstX0 *= dstScale;
+            dstY0 *= dstScale;
+            dstX1 *= dstScale;
+            dstY1 *= dstScale;
+
+            _context.Renderer.Pipeline.DrawTexture(
+                texture?.HostTexture,
+                sampler?.HostSampler,
+                new Extents2DF(srcX0, srcY0, srcX1, srcY1),
+                new Extents2DF(dstX0, dstY0, dstX1, dstY1));
+        }
+
+        /// <summary>
         /// Performs a indirect multi-draw, with parameters from a GPU buffer.
         /// </summary>
         /// <param name="engine">3D engine where this method is being called</param>
diff --git a/Ryujinx.Graphics.Gpu/Engine/Threed/ThreedClass.cs b/Ryujinx.Graphics.Gpu/Engine/Threed/ThreedClass.cs
index 5478704a..f3061c73 100644
--- a/Ryujinx.Graphics.Gpu/Engine/Threed/ThreedClass.cs
+++ b/Ryujinx.Graphics.Gpu/Engine/Threed/ThreedClass.cs
@@ -36,6 +36,7 @@ namespace Ryujinx.Graphics.Gpu.Engine.Threed
                 { nameof(ThreedClassState.SyncpointAction), new RwCallback(IncrementSyncpoint, null) },
                 { nameof(ThreedClassState.TextureBarrier), new RwCallback(TextureBarrier, null) },
                 { nameof(ThreedClassState.TextureBarrierTiled), new RwCallback(TextureBarrierTiled, null) },
+                { nameof(ThreedClassState.DrawTextureSrcY), new RwCallback(DrawTexture, null) },
                 { nameof(ThreedClassState.VbElementU8), new RwCallback(VbElementU8, null) },
                 { nameof(ThreedClassState.VbElementU16), new RwCallback(VbElementU16, null) },
                 { nameof(ThreedClassState.VbElementU32), new RwCallback(VbElementU32, null) },
@@ -252,6 +253,15 @@ namespace Ryujinx.Graphics.Gpu.Engine.Threed
         }
 
         /// <summary>
+        /// Draws a texture, without needing to specify shader programs.
+        /// </summary>
+        /// <param name="argument">Method call argument</param>
+        private void DrawTexture(int argument)
+        {
+            _drawManager.DrawTexture(this, argument);
+        }
+
+        /// <summary>
         /// Pushes four 8-bit index buffer elements.
         /// </summary>
         /// <param name="argument">Method call argument</param>
diff --git a/Ryujinx.Graphics.Gpu/Engine/Threed/ThreedClassState.cs b/Ryujinx.Graphics.Gpu/Engine/Threed/ThreedClassState.cs
index 58bc0957..165f5072 100644
--- a/Ryujinx.Graphics.Gpu/Engine/Threed/ThreedClassState.cs
+++ b/Ryujinx.Graphics.Gpu/Engine/Threed/ThreedClassState.cs
@@ -743,7 +743,18 @@ namespace Ryujinx.Graphics.Gpu.Engine.Threed
         public fixed uint ReservedF94[19];
         public RtDepthStencilState RtDepthStencilState;
         public ScreenScissorState ScreenScissorState;
-        public fixed uint ReservedFFC[89];
+        public fixed uint ReservedFFC[33];
+        public int DrawTextureDstX;
+        public int DrawTextureDstY;
+        public int DrawTextureDstWidth;
+        public int DrawTextureDstHeight;
+        public long DrawTextureDuDx;
+        public long DrawTextureDvDy;
+        public int DrawTextureSamplerId;
+        public int DrawTextureTextureId;
+        public int DrawTextureSrcX;
+        public int DrawTextureSrcY;
+        public fixed uint Reserved10B0[44];
         public Array16<VertexAttribState> VertexAttribState;
         public fixed uint Reserved11A0[31];
         public RtControl RtControl;