initial work to split into dart_filament and flutter_filament

flutter_filament/windows/opengl_texture_buffer.h

@@ -0,0 +1,51 @@
+#pragma once
+
+#ifndef _OPENGL_TEXTURE_BUFFER_H 
+#define _OPENGL_TEXTURE_BUFFER_H
+
+#include <mutex>
+
+#include <flutter/texture_registrar.h>
+#include <flutter/method_channel.h>
+#include <flutter/plugin_registrar_windows.h>
+
+#include "GL/GL.h"
+#include "GL/GLu.h"
+#include "GL/wglext.h"
+
+#include <Windows.h>
+#include <wrl.h>
+
+#include "flutter_texture_buffer.h"
+
+typedef uint32_t GLuint;
+
+namespace flutter_filament {
+
+class OpenGLTextureBuffer : public FlutterTextureBuffer {
+  public:
+    OpenGLTextureBuffer(
+        flutter::PluginRegistrarWindows* pluginRegistrar,
+        flutter::TextureRegistrar* textureRegistrar,
+        std::unique_ptr<flutter::MethodResult<flutter::EncodableValue>> result,
+        uint32_t width,
+        uint32_t height,
+        HGLRC context);
+    
+    ~OpenGLTextureBuffer();
+    GLuint glTextureId = 0;
+    std::unique_ptr<FlutterDesktopPixelBuffer> pixelBuffer;
+    std::unique_ptr<uint8_t> pixelData;
+    std::unique_ptr<flutter::TextureVariant> texture;
+  
+  private:
+    flutter::PluginRegistrarWindows* _pluginRegistrar;
+    flutter::TextureRegistrar* _textureRegistrar;
+    uint32_t _width = 0;
+    uint32_t _height = 0;
+    HGLRC _context = NULL;
+    bool logged = false;
+};
+
+}
+#endif // _OPENGL_TEXTURE_BUFFER_H