From 1a13f9707babeac30a732c8f9e902824290b1078 Mon Sep 17 00:00:00 2001
From: TellowKrinkle <tellowkrinkle@gmail.com>
Date: Thu, 4 Jun 2026 20:26:04 -0500
Subject: [PATCH] GS:MTL: GPU ROV feature detection

---
 pcsx2/GS/Renderers/Metal/GSDeviceMTL.mm     | 14 ++++++++++++++
 pcsx2/GS/Renderers/Metal/GSMTLDeviceInfo.h  |  3 +++
 pcsx2/GS/Renderers/Metal/GSMTLDeviceInfo.mm |  9 +++++++++
 3 files changed, 26 insertions(+)

diff --git a/pcsx2/GS/Renderers/Metal/GSDeviceMTL.mm b/pcsx2/GS/Renderers/Metal/GSDeviceMTL.mm
index f20bdb7d9c..ab3f47db7e 100644
--- a/pcsx2/GS/Renderers/Metal/GSDeviceMTL.mm
+++ b/pcsx2/GS/Renderers/Metal/GSDeviceMTL.mm
@@ -1295,6 +1295,19 @@ bool GSDeviceMTL::UpdateWindow()
 
 bool GSDeviceMTL::SupportsExclusiveFullscreen() const { return false; }
 
+static const char* GetROVString(const GSMTLDevice::Features& features)
+{
+	if (!features.rov)
+		return "Unsupported";
+	if (features.rov_requires_r32 && features.rov_requires_rt)
+		return "With R32 Reinterpret and RT Texture";
+	if (features.rov_requires_r32)
+		return "With R32 Reinterpret";
+	if (features.rov_requires_rt)
+		return "With RT Texture";
+	return "Supported";
+}
+
 std::string GSDeviceMTL::GetDriverInfo() const
 { @autoreleasepool {
 	std::string desc([[m_dev.dev description] UTF8String]);
@@ -1304,6 +1317,7 @@ std::string GSDeviceMTL::GetDriverInfo() const
 	desc += "\n    Memoryless Textures: " + std::string(m_dev.features.memoryless_textures ? "Supported" : "Unsupported");
 	desc += "\n    Primitive ID:        " + std::string(m_dev.features.primid              ? "Supported" : "Unsupported");
 	desc += "\n    Depth Feedback:      " + std::string(m_dev.features.depth_feedback      ? "Supported" : "Unsupported");
+	desc += "\n    ROV:                 " + std::string(GetROVString(m_dev.features));
 	desc += "\n    Shader Version:      " + std::string(to_string(m_dev.features.shader_version));
 	desc += "\n    Max Texture Size:    " + std::to_string(m_dev.features.max_texsize);
 	return desc;
diff --git a/pcsx2/GS/Renderers/Metal/GSMTLDeviceInfo.h b/pcsx2/GS/Renderers/Metal/GSMTLDeviceInfo.h
index 1a7d45a003..f8fe13d8e8 100644
--- a/pcsx2/GS/Renderers/Metal/GSMTLDeviceInfo.h
+++ b/pcsx2/GS/Renderers/Metal/GSMTLDeviceInfo.h
@@ -34,6 +34,9 @@ struct GSMTLDevice
 		bool has_fast_half          : 1;
 		bool memoryless_textures    : 1;
 		bool depth_feedback         : 1;
+		bool rov                    : 1;
+		bool rov_requires_rt        : 1;
+		bool rov_requires_r32       : 1;
 		MetalVersion shader_version;
 		int max_texsize;
 	};
diff --git a/pcsx2/GS/Renderers/Metal/GSMTLDeviceInfo.mm b/pcsx2/GS/Renderers/Metal/GSMTLDeviceInfo.mm
index 5e316931da..e8d103651c 100644
--- a/pcsx2/GS/Renderers/Metal/GSMTLDeviceInfo.mm
+++ b/pcsx2/GS/Renderers/Metal/GSMTLDeviceInfo.mm
@@ -166,6 +166,9 @@ GSMTLDevice::GSMTLDevice(MRCOwned<id<MTLDevice>> dev)
 
 	features.depth_feedback = false;
 
+	features.rov = [dev areRasterOrderGroupsSupported];
+	features.rov_requires_r32 = [dev readWriteTextureSupport] < MTLReadWriteTextureTier2;
+
 	NSString* name = [dev name];
 	if ([name containsString:@"Intel"])
 	{
@@ -193,6 +196,9 @@ GSMTLDevice::GSMTLDevice(MRCOwned<id<MTLDevice>> dev)
 		if (@available(macOS 13, iOS 16, *))
 			if ([dev supportsFamily:MTLGPUFamilyMetal3])
 				features.depth_feedback = true;
+		// ROV doesn't work on AMD GPUs with no render target
+		// Ideally the driver would insert a dummy texture for us (it does on Linux) but the Metal driver doesn't.
+		features.rov_requires_rt = true;
 	}
 	else if ([name containsString:@"NVIDIA"])
 	{
@@ -219,6 +225,9 @@ GSMTLDevice::GSMTLDevice(MRCOwned<id<MTLDevice>> dev)
 	else
 		features.slow_color_compression = [[dev name] containsString:@"AMD"] || [[dev name] isEqualToString:@"Intel HD Graphics 4000"];
 
+	if (char* env = getenv("MTL_ROV_WITH_RT"))
+		features.rov_requires_rt = env[0] == '1' || env[0] == 'y' || env[0] == 'Y';
+
 	features.max_texsize = GetMaxTextureSize(dev);
 
 	this->dev = std::move(dev);