OSMesa: Context creation compliance fixes

src/osmesa_context.c

@@ -200,6 +200,13 @@ GLFWbool _glfwCreateContextOSMesa(_GLFWwindow* window,
                           fbconfig->accumBlueBits +
                           fbconfig->accumAlphaBits;
 
+    if (ctxconfig->client == GLFW_OPENGL_ES_API)
+    {
+        _glfwInputError(GLFW_API_UNAVAILABLE,
+                        "OSMesa: OpenGL ES is not available on OSMesa");
+        return GLFW_FALSE;
+    }
+
     if (ctxconfig->share)
         share = ctxconfig->share->context.osmesa.handle;
 
@@ -227,6 +234,13 @@ GLFWbool _glfwCreateContextOSMesa(_GLFWwindow* window,
             setAttrib(OSMESA_CONTEXT_MINOR_VERSION, ctxconfig->minor);
         }
 
+        if (ctxconfig->forward)
+        {
+            _glfwInputError(GLFW_VERSION_UNAVAILABLE,
+                            "OSMesa: Foward-compatible contexts not supported");
+            return GLFW_FALSE;
+        }
+
         setAttrib(0, 0);
 
         window->context.osmesa.handle =

src/osmesa_window.c

@@ -47,18 +47,25 @@ int _glfwPlatformCreateWindow(_GLFWwindow* window,
                               const _GLFWctxconfig* ctxconfig,
                               const _GLFWfbconfig* fbconfig)
 {
-    if (!_glfwInitOSMesa())
+    if (!createNativeWindow(window, wndconfig))
         return GLFW_FALSE;
 
     if (ctxconfig->client != GLFW_NO_API)
     {
-        if (!_glfwCreateContextOSMesa(window, ctxconfig, fbconfig))
+        if (ctxconfig->source == GLFW_NATIVE_CONTEXT_API)
+        {
+            if (!_glfwInitOSMesa())
+                return GLFW_FALSE;
+            if (!_glfwCreateContextOSMesa(window, ctxconfig, fbconfig))
+                return GLFW_FALSE;
+        }
+        else
+        {
+            _glfwInputError(GLFW_API_UNAVAILABLE, "OSMesa: EGL not available");
             return GLFW_FALSE;
+        }
     }
 
-    if (!createNativeWindow(window, wndconfig))
-        return GLFW_FALSE;
-
     return GLFW_TRUE;
 }