From e696d9b3244cde9b18929acb240a301d2e28b653 Mon Sep 17 00:00:00 2001
From: kd-11 <karokidii@gmail.com>
Date: Wed, 25 Dec 2024 22:06:46 +0300
Subject: [PATCH] rsx: Add code to detect instanced draw commands

---
 rpcs3/Emu/RSX/NV47/FW/draw_call.cpp | 40 +++++++++++++++++++++++++++++
 rpcs3/Emu/RSX/NV47/FW/draw_call.hpp |  7 +++--
 2 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/rpcs3/Emu/RSX/NV47/FW/draw_call.cpp b/rpcs3/Emu/RSX/NV47/FW/draw_call.cpp
index 39c8aa01e7..2d41a0ed75 100644
--- a/rpcs3/Emu/RSX/NV47/FW/draw_call.cpp
+++ b/rpcs3/Emu/RSX/NV47/FW/draw_call.cpp
@@ -89,6 +89,45 @@ namespace rsx
 		}
 	}
 
+	bool draw_clause::check_trivially_instanced() const
+	{
+		if (draw_command_ranges.size() <= 1)
+		{
+			// Cannot instance one draw call or less
+			return false;
+		}
+
+		// For instancing all draw calls must be identical
+		const auto& ref = draw_command_ranges.front();
+		for (const auto& range : draw_command_ranges)
+		{
+			if (range.first != ref.first || range.count != ref.count)
+			{
+				return false;
+			}
+		}
+
+		if (draw_command_barriers.empty())
+		{
+			// Raise alarm here for investigation, we may be missing a corner case.
+			rsx_log.error("Instanced draw detected, but no command barriers found!");
+			return false;
+		}
+
+		// Barriers must exist, but can only involve updating transform constants (for now)
+		for (const auto& barrier : draw_command_barriers)
+		{
+			if (barrier.type != rsx::transform_constant_load_modifier_barrier &&
+				barrier.type != rsx::transform_constant_update_barrier)
+			{
+				// Only transform constant instancing is supported at the moment.
+				return false;
+			}
+		}
+
+		return true;
+	}
+
 	void draw_clause::reset(primitive_type type)
 	{
 		current_range_index = ~0u;
@@ -97,6 +136,7 @@ namespace rsx
 		command = draw_command::none;
 		primitive = type;
 		primitive_barrier_enable = false;
+		is_trivial_instanced_draw = false;
 
 		draw_command_ranges.clear();
 		draw_command_barriers.clear();
diff --git a/rpcs3/Emu/RSX/NV47/FW/draw_call.hpp b/rpcs3/Emu/RSX/NV47/FW/draw_call.hpp
index 323504ac91..fed734f025 100644
--- a/rpcs3/Emu/RSX/NV47/FW/draw_call.hpp
+++ b/rpcs3/Emu/RSX/NV47/FW/draw_call.hpp
@@ -51,6 +51,8 @@ namespace rsx
 			}
 		}
 
+		bool check_trivially_instanced() const;
+
 	public:
 		primitive_type primitive{};
 		draw_command command{};
@@ -59,6 +61,7 @@ namespace rsx
 		bool is_disjoint_primitive{};      // Set if primitive type does not rely on adjacency information
 		bool primitive_barrier_enable{};   // Set once to signal that a primitive restart barrier can be inserted
 		bool is_rendering{};               // Set while we're actually pushing the draw calls to host GPU
+		bool is_trivial_instanced_draw{};  // Set if the draw call can be executed on the host GPU as a single instanced draw.
 
 		simple_array<u32> inline_vertex_array{};
 
@@ -73,8 +76,8 @@ namespace rsx
 		{
 			// End draw call append mode
 			current_range_index = ~0u;
-
-			// TODO
+			// Check if we can instance on host
+			is_trivial_instanced_draw = check_trivially_instanced();
 		}
 
 		/**