From eb725f9e66da28568d96e9649aa9ba30fa4d5d4c Mon Sep 17 00:00:00 2001
From: Flyinghead <raphael.jean@gmail.com>
Date: Fri, 10 May 2019 11:15:44 +0200
Subject: [PATCH] x11: fix fallback to gl 3.0. fix crash when switching
 renderer.

Fallback to GL 3.1 when GL 4.3 isn't available was broken.
Fallback to GL 3.0 instead of 3.1.
Fix crash when switching renderer (per-pixel, per-triangle)
---
 core/hw/pvr/Renderer_if.cpp | 18 ++++++++++--------
 core/linux-dist/x11.cpp     | 13 ++++++++++---
 2 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/core/hw/pvr/Renderer_if.cpp b/core/hw/pvr/Renderer_if.cpp
index 0a9c5b16b..71c954e34 100644
--- a/core/hw/pvr/Renderer_if.cpp
+++ b/core/hw/pvr/Renderer_if.cpp
@@ -98,6 +98,7 @@ TA_context* _pvrrc;
 void SetREP(TA_context* cntx);
 void killtex();
 bool render_output_framebuffer();
+static void rend_create_renderer();
 
 void dump_frame(const char* file, TA_context* ctx, u8* vram, u8* vram_ref = NULL) {
 	FILE* fw = fopen(file, "wb");
@@ -266,6 +267,13 @@ bool rend_frame(TA_context* ctx, bool draw_osd) {
 
 bool rend_single_frame()
 {
+	if (renderer_changed)
+	{
+		renderer_changed = false;
+		rend_term_renderer();
+		rend_create_renderer();
+		rend_init_renderer();
+	}
 	//wait render start only if no frame pending
 	do
 	{
@@ -362,6 +370,7 @@ void rend_init_renderer()
     	}
     	printf("Selected renderer initialization failed. Falling back to default renderer.\n");
     	renderer  = fallback_renderer;
+    	fallback_renderer = NULL;	// avoid double-free
     }
 }
 
@@ -377,7 +386,6 @@ void rend_term_renderer()
 		delete fallback_renderer;
 		fallback_renderer = NULL;
 	}
-	tactx_Term();
 }
 
 void* rend_thread(void* p)
@@ -391,13 +399,6 @@ void* rend_thread(void* p)
 	{
 		if (rend_single_frame())
 			renderer->Present();
-		if (renderer_changed)
-		{
-			renderer_changed = false;
-			rend_term_renderer();
-			rend_create_renderer();
-			rend_init_renderer();
-		}
 	}
 
 	rend_term_renderer();
@@ -538,6 +539,7 @@ void rend_end_render()
 void rend_stop_renderer()
 {
 	renderer_enabled = false;
+	tactx_Term();
 }
 
 void rend_vblank()
diff --git a/core/linux-dist/x11.cpp b/core/linux-dist/x11.cpp
index aa71bdbdf..e053097be 100644
--- a/core/linux-dist/x11.cpp
+++ b/core/linux-dist/x11.cpp
@@ -361,6 +361,11 @@ void input_x11_init()
 		printf("X11 Keyboard input disabled by config.\n");
 }
 
+static int x11_error_handler(Display *, XErrorEvent *)
+{
+	return 0;
+}
+
 void x11_window_create()
 {
 	if (cfgLoadInt("pvr", "nox11", 0) == 0)
@@ -519,20 +524,22 @@ void x11_window_create()
 				GLX_CONTEXT_PROFILE_MASK_ARB, GLX_CONTEXT_CORE_PROFILE_BIT_ARB,
 				None
 			};
+			int (*old_handler)(Display *, XErrorEvent *) = XSetErrorHandler(&x11_error_handler);
 
 			x11_glc = glXCreateContextAttribsARB(x11Display, bestFbc, 0, True, context_attribs);
 			if (!x11_glc)
 			{
 				printf("Open GL 4.3 not supported\n");
-				// Try GL 3.1
+				// Try GL 3.0
 				context_attribs[1] = 3;
-				context_attribs[3] = 1;
+				context_attribs[3] = 0;
 				x11_glc = glXCreateContextAttribsARB(x11Display, bestFbc, 0, True, context_attribs);
 				if (!x11_glc)
 				{
-					die("Open GL 3.1 not supported\n");
+					die("Open GL 3.0 not supported\n");
 				}
 			}
+			XSetErrorHandler(old_handler);
 			XSync(x11Display, False);
 
 		#endif