Adding generic immediate mode drawing API and migrating microprofile.

Future changes will move elemental-forms and imgui to the common API as
well.

src/xenia/ui/gl/gl_immediate_drawer.h

@@ -0,0 +1,53 @@
+/**
+ ******************************************************************************
+ * Xenia : Xbox 360 Emulator Research Project                                 *
+ ******************************************************************************
+ * Copyright 2015 Ben Vanik. All rights reserved.                             *
+ * Released under the BSD license - see LICENSE in the root for more details. *
+ ******************************************************************************
+ */
+
+#ifndef XENIA_UI_GL_GL_IMMEDIATE_DRAWER_H_
+#define XENIA_UI_GL_GL_IMMEDIATE_DRAWER_H_
+
+#include <memory>
+
+#include "xenia/ui/gl/gl.h"
+#include "xenia/ui/immediate_drawer.h"
+
+namespace xe {
+namespace ui {
+namespace gl {
+
+class GLImmediateDrawer : public ImmediateDrawer {
+ public:
+  GLImmediateDrawer(GraphicsContext* graphics_context);
+  ~GLImmediateDrawer() override;
+
+  std::unique_ptr<ImmediateTexture> CreateTexture(uint32_t width,
+                                                  uint32_t height,
+                                                  ImmediateTextureFilter filter,
+                                                  bool repeat,
+                                                  const uint8_t* data) override;
+  void UpdateTexture(ImmediateTexture* texture, const uint8_t* data) override;
+
+  void Begin(int render_target_width, int render_target_height) override;
+  void Draw(const ImmediateDrawBatch& batch) override;
+  void End() override;
+
+ private:
+  void InitializeShaders();
+
+  GLuint program_ = 0;
+  GLuint vao_ = 0;
+  GLuint vertex_buffer_ = 0;
+  GLuint index_buffer_ = 0;
+
+  bool was_current_ = false;
+};
+
+}  // namespace gl
+}  // namespace ui
+}  // namespace xe
+
+#endif  // XENIA_UI_GL_GL_IMMEDIATE_DRAWER_H_