From f1dec3dd07d8b6a31a9cbb7757c10d003e9e8a6a Mon Sep 17 00:00:00 2001
From: CasualPokePlayer <50538166+CasualPokePlayer@users.noreply.github.com>
Date: Fri, 26 Apr 2024 13:51:20 -0700
Subject: [PATCH] C# changes for fixing GPGX drive light

---
 .../Consoles/Sega/gpgx64/GPGX.cs                    | 13 ++++++++++---
 .../Consoles/Sega/gpgx64/LibGPGX.cs                 |  2 +-
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/src/BizHawk.Emulation.Cores/Consoles/Sega/gpgx64/GPGX.cs b/src/BizHawk.Emulation.Cores/Consoles/Sega/gpgx64/GPGX.cs
index 8f2c9a5a2b..ec01cc7cf5 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Sega/gpgx64/GPGX.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Sega/gpgx64/GPGX.cs
@@ -38,7 +38,7 @@ namespace BizHawk.Emulation.Cores.Consoles.Sega.gpgx
 			}
 
 			// internally, the core caches disc sectors read into the invisible heap
-			var discBufferSize = lp.Discs.Sum(d => d.DiscData.Session1.LeadoutLBA * 2448);
+			var discBufferSize = lp.Discs.Sum(d => d.DiscData.Session1.LeadoutLBA * 2448 + d.DiscData.Session1.LeadoutLBA);
 			discBufferSize += 1024 - discBufferSize % 1024;
 
 			_elf = new WaterboxHost(new WaterboxOptions
@@ -283,8 +283,16 @@ namespace BizHawk.Emulation.Cores.Consoles.Sega.gpgx
 
 		private readonly byte[] _sectorBuffer = new byte[2448];
 
-		private void CDRead(int lba, IntPtr dest, bool subcode)
+		private void CDRead(int lba, IntPtr dest, bool subcode, bool driveLight)
 		{
+			// the core does caching of CD reads, so it doesn't need to callback to read the disc that often
+			// however, it still needs to callback to signal the drive light to be turned on
+			if (driveLight)
+			{
+				_driveLight = true;
+				return;
+			}
+
 			if ((uint)_discIndex < _cds.Length)
 			{
 				if (subcode)
@@ -296,7 +304,6 @@ namespace BizHawk.Emulation.Cores.Consoles.Sega.gpgx
 				{
 					_cdReaders[_discIndex].ReadLBA_2352(lba, _sectorBuffer, 0);
 					Marshal.Copy(_sectorBuffer, 0, dest, 2352);
-					_driveLight = true;
 				}
 			}
 		}
diff --git a/src/BizHawk.Emulation.Cores/Consoles/Sega/gpgx64/LibGPGX.cs b/src/BizHawk.Emulation.Cores/Consoles/Sega/gpgx64/LibGPGX.cs
index cd8f12744f..7cf1e6822c 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Sega/gpgx64/LibGPGX.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Sega/gpgx64/LibGPGX.cs
@@ -277,7 +277,7 @@ namespace BizHawk.Emulation.Cores.Consoles.Sega.gpgx
 		public const int CD_MAX_TRACKS = 100;
 
 		[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
-		public delegate void cd_read_cb(int lba, IntPtr dest, [MarshalAs(UnmanagedType.Bool)] bool subcode);
+		public delegate void cd_read_cb(int lba, IntPtr dest, [MarshalAs(UnmanagedType.Bool)] bool subcode, [MarshalAs(UnmanagedType.Bool)] bool driveLight);
 
 		[StructLayout(LayoutKind.Sequential)]
 		public struct CDTrack