Added MESA and SGI swap interval implementations in order to fix v-sync not being set properly on some Unix systems (#727), added error message when setting v-sync fails on Windows systems.

src/SFML/Window/Unix/GlxContext.cpp

@@ -198,8 +198,23 @@ void GlxContext::setVerticalSyncEnabled(bool enabled)
     // Make sure that extensions are initialized
     ensureExtensionsInit(m_display, DefaultScreen(m_display));
 
+    int result = 0;
+
+    // Prioritize the EXT variant and fall back to MESA or SGI if needed
+    // We use the direct pointer to the MESA entry point instead of the alias
+    // because glx.h declares the entry point as an external function
+    // which would require us to link in an additional library
     if (sfglx_ext_EXT_swap_control == sfglx_LOAD_SUCCEEDED)
         glXSwapIntervalEXT(m_display, glXGetCurrentDrawable(), enabled ? 1 : 0);
+    else if (sfglx_ext_MESA_swap_control == sfglx_LOAD_SUCCEEDED)
+        result = sf_ptrc_glXSwapIntervalMESA(enabled ? 1 : 0);
+    else if (sfglx_ext_SGI_swap_control == sfglx_LOAD_SUCCEEDED)
+        result = glXSwapIntervalSGI(enabled ? 1 : 0);
+    else
+        err() << "Setting vertical sync not supported" << std::endl;
+
+    if (result != 0)
+        err() << "Setting vertical sync failed" << std::endl;
 }
 
 

src/SFML/Window/Unix/GlxExtensions.cpp

@@ -8,6 +8,8 @@
 #define IntGetProcAddress(name) (*glXGetProcAddressARB)((const GLubyte*)name)
 
 int sfglx_ext_EXT_swap_control = sfglx_LOAD_FAILED;
+int sfglx_ext_MESA_swap_control = sfglx_LOAD_FAILED;
+int sfglx_ext_SGI_swap_control = sfglx_LOAD_FAILED;
 int sfglx_ext_ARB_multisample = sfglx_LOAD_FAILED;
 int sfglx_ext_ARB_create_context = sfglx_LOAD_FAILED;
 int sfglx_ext_ARB_create_context_profile = sfglx_LOAD_FAILED;
@@ -22,6 +24,26 @@ static int Load_EXT_swap_control(void)
     return numFailed;
 }
 
+int (CODEGEN_FUNCPTR *sf_ptrc_glXSwapIntervalMESA)(int) = NULL;
+
+static int Load_MESA_swap_control(void)
+{
+    int numFailed = 0;
+    sf_ptrc_glXSwapIntervalMESA = (int (CODEGEN_FUNCPTR *)(int))IntGetProcAddress("glXSwapIntervalMESA");
+    if(!sf_ptrc_glXSwapIntervalMESA) numFailed++;
+    return numFailed;
+}
+
+int (CODEGEN_FUNCPTR *sf_ptrc_glXSwapIntervalSGI)(int) = NULL;
+
+static int Load_SGI_swap_control(void)
+{
+    int numFailed = 0;
+    sf_ptrc_glXSwapIntervalSGI = (int (CODEGEN_FUNCPTR *)(int))IntGetProcAddress("glXSwapIntervalSGI");
+    if(!sf_ptrc_glXSwapIntervalSGI) numFailed++;
+    return numFailed;
+}
+
 GLXContext (CODEGEN_FUNCPTR *sf_ptrc_glXCreateContextAttribsARB)(Display *, GLXFBConfig, GLXContext, Bool, const int *) = NULL;
 
 static int Load_ARB_create_context(void)
@@ -40,14 +62,16 @@ typedef struct sfglx_StrToExtMap_s
     PFN_LOADFUNCPOINTERS LoadExtension;
 } sfglx_StrToExtMap;
 
-static sfglx_StrToExtMap ExtensionMap[4] = {
+static sfglx_StrToExtMap ExtensionMap[6] = {
     {"GLX_EXT_swap_control", &sfglx_ext_EXT_swap_control, Load_EXT_swap_control},
+    {"GLX_MESA_swap_control", &sfglx_ext_MESA_swap_control, Load_MESA_swap_control},
+    {"GLX_SGI_swap_control", &sfglx_ext_SGI_swap_control, Load_SGI_swap_control},
     {"GLX_ARB_multisample", &sfglx_ext_ARB_multisample, NULL},
     {"GLX_ARB_create_context", &sfglx_ext_ARB_create_context, Load_ARB_create_context},
     {"GLX_ARB_create_context_profile", &sfglx_ext_ARB_create_context_profile, NULL},
 };
 
-static int g_extensionMapSize = 4;
+static int g_extensionMapSize = 6;
 
 static sfglx_StrToExtMap *FindExtEntry(const char *extensionName)
 {
@@ -65,6 +89,8 @@ static sfglx_StrToExtMap *FindExtEntry(const char *extensionName)
 static void ClearExtensionVars(void)
 {
     sfglx_ext_EXT_swap_control = sfglx_LOAD_FAILED;
+    sfglx_ext_MESA_swap_control = sfglx_LOAD_FAILED;
+    sfglx_ext_SGI_swap_control = sfglx_LOAD_FAILED;
     sfglx_ext_ARB_multisample = sfglx_LOAD_FAILED;
     sfglx_ext_ARB_create_context = sfglx_LOAD_FAILED;
     sfglx_ext_ARB_create_context_profile = sfglx_LOAD_FAILED;

src/SFML/Window/Unix/GlxExtensions.hpp

@@ -118,6 +118,8 @@ extern "C" {
 #endif /*__cplusplus*/
 
 extern int sfglx_ext_EXT_swap_control;
+extern int sfglx_ext_MESA_swap_control;
+extern int sfglx_ext_SGI_swap_control;
 extern int sfglx_ext_ARB_multisample;
 extern int sfglx_ext_ARB_create_context;
 extern int sfglx_ext_ARB_create_context_profile;
@@ -144,6 +146,15 @@ extern void (CODEGEN_FUNCPTR *sf_ptrc_glXSwapIntervalEXT)(Display *, GLXDrawable
 #define glXSwapIntervalEXT sf_ptrc_glXSwapIntervalEXT
 #endif /*GLX_EXT_swap_control*/
 
+// Declare entry point even if GLX header already provides glXSwapIntervalMESA
+// We won't make use of an alias here
+extern int (CODEGEN_FUNCPTR *sf_ptrc_glXSwapIntervalMESA)(int);
+
+#ifndef GLX_SGI_swap_control
+#define GLX_SGI_swap_control 1
+extern int (CODEGEN_FUNCPTR *sf_ptrc_glXSwapIntervalSGI)(int);
+#define glXSwapIntervalSGI sf_ptrc_glXSwapIntervalSGI
+#endif /*GLX_SGI_swap_control*/
 
 #ifndef GLX_ARB_create_context
 #define GLX_ARB_create_context 1

src/SFML/Window/Unix/GlxExtensions.txt

@@ -4,6 +4,8 @@
 // lua LoadGen.lua -style=pointer_c -spec=glX -indent=space -prefix=sf -extfile=GlxExtensions.txt GlxExtensions
 
 EXT_swap_control
+// MESA_swap_control
+SGI_swap_control
 GLX_ARB_multisample
 GLX_ARB_create_context
 GLX_ARB_create_context_profile

src/SFML/Window/Win32/WglContext.cpp

@@ -175,7 +175,10 @@ void WglContext::setVerticalSyncEnabled(bool enabled)
     ensureExtensionsInit(m_deviceContext);
 
     if (sfwgl_ext_EXT_swap_control == sfwgl_LOAD_SUCCEEDED)
-        wglSwapIntervalEXT(enabled ? 1 : 0);
+    {
+        if (wglSwapIntervalEXT(enabled ? 1 : 0) == FALSE)
+            err() << "Setting vertical sync failed" << std::endl;
+    }
     else
     {
         // wglSwapIntervalEXT not supported