Adds the function Map::terminate() to allow all GL resources held

by the map to be released immediately.

Map::terminate() will call any GL functions on the current thread
without blocking or defering to the rendering thread.

This function allows a GL context to be destroyed and recreated
safely without having to delete the Map object.

Fixes mapbox/mapbox-gl-native#341

Conflicts:
	include/llmr/renderer/painter.hpp
	test/headless.cpp

2 files changed, 5 insertions, 0 deletions

diff --git a/include/mbgl/map/map.hpp b/include/mbgl/map/map.hpp
index fba38879ed..0d2926d04b 100644
--- a/include/mbgl/map/map.hpp
+++ b/include/mbgl/map/map.hpp
@@ -53,6 +53,9 @@ public:
     // Triggers a cleanup that releases resources.
     void cleanup();
 
+    // Releases resources immediately
+    void terminate();
+
     // Controls buffer swapping.
     bool needsSwap();
     void swapped();
diff --git a/include/mbgl/renderer/painter.hpp b/include/mbgl/renderer/painter.hpp
index 75529d1136..15331b9b67 100644
--- a/include/mbgl/renderer/painter.hpp
+++ b/include/mbgl/renderer/painter.hpp
@@ -63,6 +63,7 @@ public:
     // lazy initialization) in case rendering continues.
     void cleanup();
 
+    void terminate();
 
     // Renders the backdrop of the OpenGL view. This also paints in areas where we don't have any
     // tiles whatsoever.
@@ -123,6 +124,7 @@ public:
 
 private:
     void setupShaders();
+    void deleteShaders();
     mat4 translatedMatrix(const mat4& matrix, const std::array<float, 2> &translation, const Tile::ID &id, TranslateAnchorType anchor);
 
     void prepareTile(const Tile& tile);