cleanup error-handling in SDL_egl.c

- always set error message in SDL_EGL_ChooseConfig / SDL_EGL_CreateContext
- assume SDL_EGL_DeleteContext does not alter the error message
- sync generic error message of SDL_EGL_MakeCurrent with SDL_EGL_Get/SetSwapInterval
- do not overwrite error message of SDL_EGL_ChooseConfig in WINRT_CreateWindow

src/video/SDL_egl.c

@@ -909,8 +909,7 @@ SDL_EGL_ChooseConfig(_THIS)
     int ret;
 
     if (!_this->egl_data) {
-        /* The EGL library wasn't loaded, SDL_GetError() should have info */
-        return -1;
+        return SDL_SetError("EGL not initialized");
     }
 
     /* Try with EGL_CONFIG_CAVEAT set to EGL_NONE, to avoid any EGL_SLOW_CONFIG or EGL_NON_CONFORMANT_CONFIG */
@@ -943,7 +942,7 @@ SDL_EGL_CreateContext(_THIS, EGLSurface egl_surface)
     SDL_bool profile_es = (profile_mask == SDL_GL_CONTEXT_PROFILE_ES);
 
     if (!_this->egl_data) {
-        /* The EGL library wasn't loaded, SDL_GetError() should have info */
+        SDL_SetError("EGL not initialized");
         return NULL;
     }
 
@@ -1044,16 +1043,8 @@ SDL_EGL_CreateContext(_THIS, EGLSurface egl_surface)
     _this->egl_data->egl_swapinterval = 0;
 
     if (SDL_EGL_MakeCurrent(_this, egl_surface, egl_context) < 0) {
-        /* Save the SDL error set by SDL_EGL_MakeCurrent */
-        char errorText[1024];
-        SDL_strlcpy(errorText, SDL_GetError(), SDL_arraysize(errorText));
-
-        /* Delete the context, which may alter the value returned by SDL_GetError() */
+        /* Delete the context */
         SDL_EGL_DeleteContext(_this, egl_context);
-
-        /* Restore the SDL error */
-        SDL_SetError("%s", errorText);
-
         return NULL;
     }
 
@@ -1096,7 +1087,7 @@ SDL_EGL_MakeCurrent(_THIS, EGLSurface egl_surface, SDL_GLContext context)
     EGLContext egl_context = (EGLContext) context;
 
     if (!_this->egl_data) {
-        return SDL_SetError("OpenGL not initialized");
+        return SDL_SetError("EGL not initialized");
     }
 
     if (!_this->egl_data->eglMakeCurrent) {
@@ -1104,7 +1095,7 @@ SDL_EGL_MakeCurrent(_THIS, EGLSurface egl_surface, SDL_GLContext context)
             /* Can't do the nothing there is to do? Probably trying to cleanup a failed startup, just return. */
             return 0;
         } else {
-            return SDL_SetError("OpenGL not initialized");  /* something clearly went wrong somewhere. */
+            return SDL_SetError("EGL not initialized");  /* something clearly went wrong somewhere. */
         }
     }
 

src/video/winrt/SDL_winrtvideo.cpp

@@ -670,9 +670,8 @@ WINRT_CreateWindow(_THIS, SDL_Window * window)
          * be passed into eglCreateWindowSurface.
          */
         if (SDL_EGL_ChooseConfig(_this) != 0) {
-            char buf[512];
-            SDL_snprintf(buf, sizeof(buf), "SDL_EGL_ChooseConfig failed: %s", SDL_GetError());
-            return SDL_SetError("%s", buf);
+            /* SDL_EGL_ChooseConfig failed, SDL_GetError() should have info */
+            return -1; 
         }
 
         if (video_data->winrtEglWindow) {   /* ... is the 'old' version of ANGLE/WinRT being used? */