- Relocated OpenGLDevice, OpenGLShader, OpenGLBuffer, OpenGLVertexArray, OpenGLTexture to engine/
- Updated engine/CMakeLists.txt to include OpenGL backend source files
- Updated tests/OpenGL/CMakeLists.txt to use engine backend
- Added OpenGLTexture class implementation
- Added OpenGLBuffer class for VBO/IBO management
- Added OpenGLVertexArray class for VAO management
- Updated CMakeLists.txt to include new source files
- Created OpenGLShader class for shader compilation
- Supports compiling from file or source code
- Provides uniform setting methods (SetInt, SetFloat, SetVec3, SetMat4)
- Integrated with GLAD for OpenGL function loading
- Created OpenGLDevice class for window and OpenGL context management
- Added CreateWindow() and InitializeWithExistingWindow() methods
- Integrated with GLFW and GLAD
- Added to tests/OpenGL as test target
This is the first step in building the OpenGL RHI backend parallel to D3D12.