From db59a4f9af462e14d23a752caf3069b4fcf5bd7f Mon Sep 17 00:00:00 2001
From: Emile Belanger <emile.belanger@gmail.com>
Date: Mon, 20 Sep 2021 21:40:47 +0100
Subject: [PATCH] Add buffer synchronisation for GLES when using mapped
 buffers.

---
 src/common/rendering/gles/gles_buffers.cpp    | 34 ++++++++++++++++---
 src/common/rendering/gles/gles_buffers.h      |  4 +++
 .../rendering/gles/gles_framebuffer.cpp       |  2 ++
 src/common/rendering/gles/gles_system.cpp     |  1 +
 .../rendering/hwrenderer/data/buffers.h       |  2 +-
 5 files changed, 37 insertions(+), 6 deletions(-)

diff --git a/src/common/rendering/gles/gles_buffers.cpp b/src/common/rendering/gles/gles_buffers.cpp
index 61296f3627a..58fe0e016ac 100644
--- a/src/common/rendering/gles/gles_buffers.cpp
+++ b/src/common/rendering/gles/gles_buffers.cpp
@@ -232,6 +232,34 @@ void GLBuffer::Resize(size_t newsize)
 	}
 }
 
+void GLBuffer::GPUDropSync()
+{
+#if !(USE_GLES2)  // Only applicable when running on desktop for now
+	if (mGLSync != NULL)
+	{
+		glDeleteSync(mGLSync);
+	}
+
+	mGLSync = glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, 0);
+#endif
+}
+
+void GLBuffer::GPUWaitSync()
+{
+#if !(USE_GLES2)  // Only applicable when running on desktop for now
+	GLenum status = glClientWaitSync(mGLSync, GL_SYNC_FLUSH_COMMANDS_BIT, 1000 * 1000 * 50); // Wait for a max of 50ms...
+
+	if (status != GL_ALREADY_SIGNALED && status != GL_CONDITION_SATISFIED)
+	{
+		//Printf("Error on glClientWaitSync: %d\n", status);
+	}
+
+	glDeleteSync(mGLSync);
+
+	mGLSync = NULL;
+#endif
+}
+
 
 //===========================================================================
 //
@@ -287,16 +315,12 @@ void GLDataBuffer::BindRange(FRenderState *state, size_t start, size_t length)
 	if (mBindingPoint == 3)// VIEWPOINT_BINDINGPOINT
 	{
 		static_cast<FGLRenderState*>(state)->ApplyViewport(memory + start);
-	}
-	else
-	{
-		//glBindBufferRange(mUseType, mBindingPoint, mBufferId, start, length);
 	} 
 }
 
 void GLDataBuffer::BindBase()
 {
-	//glBindBufferBase(mUseType, mBindingPoint, mBufferId);
+
 }
 
 
diff --git a/src/common/rendering/gles/gles_buffers.h b/src/common/rendering/gles/gles_buffers.h
index de51ff31bf6..0bd2053512b 100644
--- a/src/common/rendering/gles/gles_buffers.h
+++ b/src/common/rendering/gles/gles_buffers.h
@@ -19,6 +19,7 @@ class GLBuffer : virtual public IBuffer
 	int mAllocationSize = 0;
 	bool mPersistent = false;
 	bool nomap = true;
+	GLsync mGLSync = 0;
 
 	bool isData = false;
 	char *memory = nullptr;
@@ -32,6 +33,9 @@ class GLBuffer : virtual public IBuffer
 	void Resize(size_t newsize) override;
 	void *Lock(unsigned int size) override;
 	void Unlock() override;
+
+	void GPUDropSync();
+	void GPUWaitSync();
 public:
 	void Bind();
 	void Upload(size_t start, size_t end);
diff --git a/src/common/rendering/gles/gles_framebuffer.cpp b/src/common/rendering/gles/gles_framebuffer.cpp
index 658a8aebfe1..3a74ee6bc16 100644
--- a/src/common/rendering/gles/gles_framebuffer.cpp
+++ b/src/common/rendering/gles/gles_framebuffer.cpp
@@ -240,11 +240,13 @@ void OpenGLFrameBuffer::Swap()
 	Finish.Reset();
 	Finish.Clock();
 
+	mVertexData->DropSync();
 
 	FPSLimit();
 	SwapBuffers();
 	
 	mVertexData->NextPipelineBuffer();
+	mVertexData->WaitSync();
 
 	RenderState()->SetVertexBuffer(screen->mVertexData); // Needed for Raze because it does not reset it
 
diff --git a/src/common/rendering/gles/gles_system.cpp b/src/common/rendering/gles/gles_system.cpp
index a72e3f933c5..5ad3a157dbd 100644
--- a/src/common/rendering/gles/gles_system.cpp
+++ b/src/common/rendering/gles/gles_system.cpp
@@ -15,6 +15,7 @@ EXTERN_CVAR(Bool, gl_customshader);
 
 PFNGLMAPBUFFERRANGEEXTPROC glMapBufferRange = NULL;
 PFNGLUNMAPBUFFEROESPROC glUnmapBuffer = NULL;
+
 #ifdef __ANDROID__
 #include <dlfcn.h>
 
diff --git a/src/common/rendering/hwrenderer/data/buffers.h b/src/common/rendering/hwrenderer/data/buffers.h
index 7f4402c1c3f..586e5caa02c 100644
--- a/src/common/rendering/hwrenderer/data/buffers.h
+++ b/src/common/rendering/hwrenderer/data/buffers.h
@@ -6,7 +6,7 @@
 class FRenderState;
 
 #ifdef __ANDROID__
-#define HW_MAX_PIPELINE_BUFFERS 8
+#define HW_MAX_PIPELINE_BUFFERS 4
 #define HW_BLOCK_SSBO 1
 #else
 // On desktop this is only useful fpr letting the GPU run in parallel with the playsim and for that 2 buffers are enough.