From 14f5329fd4e1a8c09893864a495af55d82368068 Mon Sep 17 00:00:00 2001
From: Giuseppe Gorgoglione <gorgogsp@gmail.com>
Date: Fri, 15 Jul 2016 13:32:36 +0200
Subject: [PATCH] BGFX: fix crash when bgfx effect folder is not present or
 incomplete

BGFX renderer requires some effects also when post-processing is disabled. If they are not available, MAME complains about missing effect files, but then goes on and crashes soon after printing the backtrace. This fix just exits gracefully when effect files are incomplete and falls back to a different renderer if the bgfx folder is missing at all, warning the user in advance.
---
 src/osd/modules/render/drawbgfx.cpp | 20 ++++++++++++++++++++
 src/osd/modules/render/drawbgfx.h   |  2 +-
 src/osd/windows/window.cpp          |  2 +-
 3 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/src/osd/modules/render/drawbgfx.cpp b/src/osd/modules/render/drawbgfx.cpp
index aaf47eb344e..4a3d6711c7c 100644
--- a/src/osd/modules/render/drawbgfx.cpp
+++ b/src/osd/modules/render/drawbgfx.cpp
@@ -235,6 +235,12 @@ int renderer_bgfx::create()
 	m_screen_effect[2] = m_effects->effect("screen_multiply");
 	m_screen_effect[3] = m_effects->effect("screen_add");
 
+	if (   m_gui_effect[0] == nullptr ||    m_gui_effect[1] == nullptr ||    m_gui_effect[2] == nullptr ||    m_gui_effect[3] == nullptr ||
+		m_screen_effect[0] == nullptr || m_screen_effect[1] == nullptr || m_screen_effect[2] == nullptr || m_screen_effect[3] == nullptr)
+	{
+		fatalerror("BGFX: Unable to load required shaders. Please check and reinstall the %s folder\n", m_options.bgfx_path());
+	}
+
 	m_chains = new chain_manager(win->machine(), m_options, *m_textures, *m_targets, *m_effects, win->m_index, *this);
 	m_sliders_dirty = true;
 
@@ -283,6 +289,20 @@ void renderer_bgfx::record()
 	}
 }
 
+bool renderer_bgfx::init(running_machine &machine)
+{
+	const char *bgfx_path = downcast<osd_options &>(machine.options()).bgfx_path();
+	
+	osd::directory::ptr directory = osd::directory::open(bgfx_path);
+	if (directory == nullptr)
+	{
+		osd_printf_verbose("Unable to find the %s folder. Please reinstall it to use the BGFX renderer\n", bgfx_path);
+		return true;
+	}
+	
+	return false;
+}
+
 void renderer_bgfx::exit()
 {
 	imguiDestroy();
diff --git a/src/osd/modules/render/drawbgfx.h b/src/osd/modules/render/drawbgfx.h
index 91dcfae03c2..af7c9dd47e4 100644
--- a/src/osd/modules/render/drawbgfx.h
+++ b/src/osd/modules/render/drawbgfx.h
@@ -36,7 +36,7 @@ public:
 	renderer_bgfx(std::shared_ptr<osd_window> w);
 	virtual ~renderer_bgfx();
 
-	static void init(running_machine &machine) { }
+	static bool init(running_machine &machine);
 	static void exit();
 
 	virtual int create() override;
diff --git a/src/osd/windows/window.cpp b/src/osd/windows/window.cpp
index cda1adb7562..b1cc369c0af 100644
--- a/src/osd/windows/window.cpp
+++ b/src/osd/windows/window.cpp
@@ -172,7 +172,7 @@ bool windows_osd_interface::window_init()
 				error = renderer_gdi::init(machine());
 				break;
 			case VIDEO_MODE_BGFX:
-				renderer_bgfx::init(machine());
+				error = renderer_bgfx::init(machine());
 				break;
 #if (USE_OPENGL)
 			case VIDEO_MODE_OPENGL: