From 57f61b7e3255f61ed32f9957fe4c68e83c54ef8a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Branimir=20Karad=C5=BEi=C4=87?= <branimirkaradzic@gmail.com>
Date: Thu, 21 May 2015 16:45:24 -0700
Subject: [PATCH] Added ability to run in single-thread mode without rebuild.

---
 src/bgfx.cpp | 21 +++++++++++++--------
 src/bgfx_p.h | 34 ++++++++++++++++++++++++----------
 2 files changed, 37 insertions(+), 18 deletions(-)

diff --git a/src/bgfx.cpp b/src/bgfx.cpp
index 42daed16..235e3978 100644
--- a/src/bgfx.cpp
+++ b/src/bgfx.cpp
@@ -7,7 +7,7 @@
 
 namespace bgfx
 {
-#define BGFX_MAIN_THREAD_MAGIC 0x78666762
+#define BGFX_MAIN_THREAD_MAGIC UINT32_C(0x78666762)
 
 #if BGFX_CONFIG_MULTITHREADED && !BX_PLATFORM_OSX && !BX_PLATFORM_IOS
 #	define BGFX_CHECK_MAIN_THREAD() \
@@ -353,7 +353,6 @@ namespace bgfx
 
 	void blit(RendererContextI* _renderCtx, TextVideoMemBlitter& _blitter, const TextVideoMem& _mem)
 	{
-		BGFX_CHECK_RENDER_THREAD();
 		struct Vertex
 		{
 			float m_x;
@@ -762,6 +761,7 @@ namespace bgfx
 		if (NULL == s_ctx)
 		{
 			s_renderFrameCalled = true;
+			s_threadIndex = ~BGFX_MAIN_THREAD_MAGIC;
 			return RenderFrame::NoContext;
 		}
 
@@ -919,16 +919,21 @@ namespace bgfx
 			// When bgfx::renderFrame is called before init render thread
 			// should not be created.
 			BX_TRACE("Application called bgfx::renderFrame directly, not creating render thread.");
+			m_singleThreaded = ~BGFX_MAIN_THREAD_MAGIC == s_threadIndex;
 		}
 		else
 		{
 			BX_TRACE("Creating rendering thread.");
 			m_thread.init(renderThread, this);
+			m_singleThreaded = false;
 		}
 #else
 		BX_TRACE("Multithreaded renderer is disabled.");
+		m_singleThreaded = true;
 #endif // BGFX_CONFIG_MULTITHREADED
 
+		s_threadIndex = BGFX_MAIN_THREAD_MAGIC;
+
 		for (uint32_t ii = 0; ii < BX_COUNTOF(m_viewRemap); ++ii)
 		{
 			m_viewRemap[ii] = uint8_t(ii);
@@ -977,6 +982,10 @@ namespace bgfx
 		g_caps.rendererType = m_renderCtx->getRendererType();
 		initAttribTypeSizeTable(g_caps.rendererType);
 
+		g_caps.supported |= 0
+			| (BX_ENABLED(BGFX_CONFIG_MULTITHREADED) && !m_singleThreaded ? BGFX_CAPS_RENDERER_MULTITHREADED : 0)
+			;
+
 		dumpCaps();
 
 		m_textVideoMemBlitter.init();
@@ -1166,7 +1175,8 @@ namespace bgfx
 
 		bx::xchg(m_render, m_submit);
 
-		if (!BX_ENABLED(BGFX_CONFIG_MULTITHREADED) )
+		if (!BX_ENABLED(BGFX_CONFIG_MULTITHREADED)
+		||  m_singleThreaded)
 		{
 			renderFrame();
 		}
@@ -1986,9 +1996,6 @@ again:
 		BX_TRACE("Init...");
 
 		memset(&g_caps, 0, sizeof(g_caps) );
-		g_caps.supported = 0
-			| (BGFX_CONFIG_MULTITHREADED ? BGFX_CAPS_RENDERER_MULTITHREADED : 0)
-			;
 		g_caps.maxViews     = BGFX_CONFIG_MAX_VIEWS;
 		g_caps.maxDrawCalls = BGFX_CONFIG_MAX_DRAW_CALLS;
 		g_caps.maxFBAttachments = 1;
@@ -2016,8 +2023,6 @@ again:
 				s_callbackStub = BX_NEW(g_allocator, CallbackStub);
 		}
 
-		s_threadIndex = BGFX_MAIN_THREAD_MAGIC;
-
 		s_ctx = BX_ALIGNED_NEW(g_allocator, Context, 16);
 		s_ctx->init(_type);
 
diff --git a/src/bgfx_p.h b/src/bgfx_p.h
index c098f743..22410045 100644
--- a/src/bgfx_p.h
+++ b/src/bgfx_p.h
@@ -1910,6 +1910,7 @@ namespace bgfx
 			, m_rendererInitialized(false)
 			, m_exit(false)
 			, m_flipAfterRender(false)
+			, m_singleThreaded(false)
 		{
 		}
 
@@ -3446,28 +3447,40 @@ namespace bgfx
 #if BGFX_CONFIG_MULTITHREADED
 		void gameSemPost()
 		{
-			m_gameSem.post();
+			if (!m_singleThreaded)
+			{
+				m_gameSem.post();
+			}
 		}
 
 		void gameSemWait()
 		{
-			int64_t start = bx::getHPCounter();
-			bool ok = m_gameSem.wait();
-			BX_CHECK(ok, "Semaphore wait failed."); BX_UNUSED(ok);
-			m_render->m_waitSubmit = bx::getHPCounter()-start;
+			if (!m_singleThreaded)
+			{
+				int64_t start = bx::getHPCounter();
+				bool ok = m_gameSem.wait();
+				BX_CHECK(ok, "Semaphore wait failed."); BX_UNUSED(ok);
+				m_render->m_waitSubmit = bx::getHPCounter()-start;
+			}
 		}
 
 		void renderSemPost()
 		{
-			m_renderSem.post();
+			if (!m_singleThreaded)
+			{
+				m_renderSem.post();
+			}
 		}
 
 		void renderSemWait()
 		{
-			int64_t start = bx::getHPCounter();
-			bool ok = m_renderSem.wait();
-			BX_CHECK(ok, "Semaphore wait failed."); BX_UNUSED(ok);
-			m_submit->m_waitRender = bx::getHPCounter() - start;
+			if (!m_singleThreaded)
+			{
+				int64_t start = bx::getHPCounter();
+				bool ok = m_renderSem.wait();
+				BX_CHECK(ok, "Semaphore wait failed."); BX_UNUSED(ok);
+				m_submit->m_waitRender = bx::getHPCounter() - start;
+			}
 		}
 
 		bx::Semaphore m_renderSem;
@@ -3598,6 +3611,7 @@ namespace bgfx
 		bool m_rendererInitialized;
 		bool m_exit;
 		bool m_flipAfterRender;
+		bool m_singleThreaded;
 
 		typedef UpdateBatchT<256> TextureUpdateBatch;
 		BX_ALIGN_DECL_CACHE_LINE(TextureUpdateBatch m_textureUpdateBatch);