1 files changed, 130 insertions, 0 deletions
diff --git a/src/Ryujinx.Graphics.Gpu/Engine/Threed/ConditionalRendering.cs b/src/Ryujinx.Graphics.Gpu/Engine/Threed/ConditionalRendering.cs
new file mode 100644
index 00000000..a6b62a4a
--- /dev/null
+++ b/src/Ryujinx.Graphics.Gpu/Engine/Threed/ConditionalRendering.cs
@@ -0,0 +1,130 @@
+using Ryujinx.Common.Logging;
+using Ryujinx.Graphics.GAL;
+using Ryujinx.Graphics.Gpu.Engine.Types;
+using Ryujinx.Graphics.Gpu.Memory;
+
+namespace Ryujinx.Graphics.Gpu.Engine.Threed
+{
+    /// <summary>
+    /// Helper methods used for conditional rendering.
+    /// </summary>
+    static class ConditionalRendering
+    {
+        /// <summary>
+        /// Checks if draws and clears should be performed, according
+        /// to currently set conditional rendering conditions.
+        /// </summary>
+        /// <param name="context">GPU context</param>
+        /// <param name="memoryManager">Memory manager bound to the channel currently executing</param>
+        /// <param name="address">Conditional rendering buffer address</param>
+        /// <param name="condition">Conditional rendering condition</param>
+        /// <returns>True if rendering is enabled, false otherwise</returns>
+        public static ConditionalRenderEnabled GetRenderEnable(GpuContext context, MemoryManager memoryManager, GpuVa address, Condition condition)
+        {
+            switch (condition)
+            {
+                case Condition.Always:
+                    return ConditionalRenderEnabled.True;
+                case Condition.Never:
+                    return ConditionalRenderEnabled.False;
+                case Condition.ResultNonZero:
+                    return CounterNonZero(context, memoryManager, address.Pack());
+                case Condition.Equal:
+                    return CounterCompare(context, memoryManager, address.Pack(), true);
+                case Condition.NotEqual:
+                    return CounterCompare(context, memoryManager, address.Pack(), false);
+            }
+
+            Logger.Warning?.Print(LogClass.Gpu, $"Invalid conditional render condition \"{condition}\".");
+
+            return ConditionalRenderEnabled.True;
+        }
+
+        /// <summary>
+        /// Checks if the counter value at a given GPU memory address is non-zero.
+        /// </summary>
+        /// <param name="context">GPU context</param>
+        /// <param name="memoryManager">Memory manager bound to the channel currently executing</param>
+        /// <param name="gpuVa">GPU virtual address of the counter value</param>
+        /// <returns>True if the value is not zero, false otherwise. Returns host if handling with host conditional rendering</returns>
+        private static ConditionalRenderEnabled CounterNonZero(GpuContext context, MemoryManager memoryManager, ulong gpuVa)
+        {
+            ICounterEvent evt = memoryManager.CounterCache.FindEvent(gpuVa);
+
+            if (evt == null)
+            {
+                return ConditionalRenderEnabled.False;
+            }
+
+            if (context.Renderer.Pipeline.TryHostConditionalRendering(evt, 0L, false))
+            {
+                return ConditionalRenderEnabled.Host;
+            }
+            else
+            {
+                evt.Flush();
+                return (memoryManager.Read<ulong>(gpuVa, true) != 0) ? ConditionalRenderEnabled.True : ConditionalRenderEnabled.False;
+            }
+        }
+
+        /// <summary>
+        /// Checks if the counter at a given GPU memory address passes a specified equality comparison.
+        /// </summary>
+        /// <param name="context">GPU context</param>
+        /// <param name="memoryManager">Memory manager bound to the channel currently executing</param>
+        /// <param name="gpuVa">GPU virtual address</param>
+        /// <param name="isEqual">True to check if the values are equal, false to check if they are not equal</param>
+        /// <returns>True if the condition is met, false otherwise. Returns host if handling with host conditional rendering</returns>
+        private static ConditionalRenderEnabled CounterCompare(GpuContext context, MemoryManager memoryManager, ulong gpuVa, bool isEqual)
+        {
+            ICounterEvent evt = FindEvent(memoryManager.CounterCache, gpuVa);
+            ICounterEvent evt2 = FindEvent(memoryManager.CounterCache, gpuVa + 16);
+
+            bool useHost;
+
+            if (evt != null && evt2 == null)
+            {
+                useHost = context.Renderer.Pipeline.TryHostConditionalRendering(evt, memoryManager.Read<ulong>(gpuVa + 16), isEqual);
+            }
+            else if (evt == null && evt2 != null)
+            {
+                useHost = context.Renderer.Pipeline.TryHostConditionalRendering(evt2, memoryManager.Read<ulong>(gpuVa), isEqual);
+            }
+            else if (evt != null && evt2 != null)
+            {
+                useHost = context.Renderer.Pipeline.TryHostConditionalRendering(evt, evt2, isEqual);
+            }
+            else
+            {
+                useHost = false;
+            }
+
+            if (useHost)
+            {
+                return ConditionalRenderEnabled.Host;
+            }
+            else
+            {
+                evt?.Flush();
+                evt2?.Flush();
+
+                ulong x = memoryManager.Read<ulong>(gpuVa, true);
+                ulong y = memoryManager.Read<ulong>(gpuVa + 16, true);
+
+                return (isEqual ? x == y : x != y) ? ConditionalRenderEnabled.True : ConditionalRenderEnabled.False;
+            }
+        }
+
+        /// <summary>
+        /// Tries to find a counter that is supposed to be written at the specified address,
+        /// returning the related event.
+        /// </summary>
+        /// <param name="counterCache">GPU counter cache to search on</param>
+        /// <param name="gpuVa">GPU virtual address where the counter is supposed to be written</param>
+        /// <returns>The counter event, or null if not present</returns>
+        private static ICounterEvent FindEvent(CounterCache counterCache, ulong gpuVa)
+        {
+            return counterCache.FindEvent(gpuVa);
+        }
+    }
+}