[core] move HeadlessBackend extension initialization code into Impl

1 files changed, 11 insertions, 10 deletions

diff --git a/platform/default/headless_backend_osmesa.cpp b/platform/default/headless_backend_osmesa.cpp
index 4cb0bfc5c4..0da1caf9af 100644
--- a/platform/default/headless_backend_osmesa.cpp
+++ b/platform/default/headless_backend_osmesa.cpp
@@ -7,8 +7,9 @@
 
 namespace mbgl {
 
-struct OSMesaImpl : public HeadlessBackend::Impl {
-    OSMesaImpl() {
+class OSMesaBackendImpl : public HeadlessBackend::Impl {
+public:
+    OSMesaBackendImpl() {
 #if OSMESA_MAJOR_VERSION * 100 + OSMESA_MINOR_VERSION >= 305
         glContext = OSMesaCreateContextExt(OSMESA_RGBA, 16, 0, 0, nullptr);
 #else
@@ -19,10 +20,14 @@ struct OSMesaImpl : public HeadlessBackend::Impl {
         }
     }
 
-    ~OSMesaImpl() final {
+    ~OSMesaBackendImpl() final {
         OSMesaDestroyContext(glContext);
     }
 
+    gl::ProcAddress getExtensionFunctionPointer(const char* name) final {
+        return OSMesaGetProcAddress(name);
+    }
+
     void activateContext() final {
         if (!OSMesaMakeCurrent(glContext, &fakeBuffer, GL_UNSIGNED_BYTE, 1, 1)) {
             throw std::runtime_error("Switching OpenGL context failed.\n");
@@ -34,13 +39,9 @@ private:
     GLubyte fakeBuffer = 0;
 };
 
-gl::ProcAddress HeadlessBackend::initializeExtension(const char* name) {
-    return OSMesaGetProcAddress(name);
-}
-
-void HeadlessBackend::createContext() {
-    assert(!hasContext());
-    impl = std::make_unique<OSMesaImpl>();
+void HeadlessBackend::createImpl() {
+    assert(!impl);
+    impl = std::make_unique<OSMesaBackendImpl>();
 }
 
 } // namespace mbgl