GPUBackend: Add new GPUBackend object to manage GL object allocations

This just set a global object responsible for allocating new objects
in a thread safe way without needing any GPUContext bound to this
thread.

This also introduce the GLContext which will contain all the GL related
functions for the current context.

1 files changed, 42 insertions, 2 deletions

diff --git a/source/blender/gpu/intern/gpu_context_private.h b/source/blender/gpu/intern/gpu_context_private.h
index 08fbefe3b3f..374a05bc25f 100644
--- a/source/blender/gpu/intern/gpu_context_private.h
+++ b/source/blender/gpu/intern/gpu_context_private.h
@@ -27,12 +27,52 @@
 
 #include "GPU_context.h"
 
+/* TODO cleanup this ifdef */
 #ifdef __cplusplus
-extern "C" {
-#endif
+
+#  include <mutex>
+#  include <pthread.h>
+#  include <string.h>
+#  include <unordered_set>
+#  include <vector>
 
 struct GPUFrameBuffer;
 
+struct GPUContext {
+  GLuint default_vao;
+  GLuint default_framebuffer;
+  GPUFrameBuffer *current_fbo;
+  std::unordered_set<GPUBatch *> batches; /* Batches that have VAOs from this context */
+#  ifdef DEBUG
+  std::unordered_set<GPUFrameBuffer *>
+      framebuffers; /* Framebuffers that have FBO from this context */
+#  endif
+  struct GPUMatrixState *matrix_state;
+  std::vector<GLuint> orphaned_vertarray_ids;
+  std::vector<GLuint> orphaned_framebuffer_ids;
+  std::mutex orphans_mutex; /* todo: try spinlock instead */
+#  if TRUST_NO_ONE
+  pthread_t thread; /* Thread on which this context is active. */
+  bool thread_is_used;
+#  endif
+
+  GPUContext()
+  {
+#  if TRUST_NO_ONE
+    thread_is_used = false;
+#  endif
+    current_fbo = 0;
+  };
+
+  virtual ~GPUContext(){};
+};
+
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 GLuint GPU_vao_default(void);
 GLuint GPU_framebuffer_default(void);