Define new getter methods for the screen width and height with their corresponding member variables

Create a new function initializeRenderBuffer(), which creates an off-screen buffer to render the scene:

...
class GraphicsManager {
public:
    ...
    int32_t getRenderWidth() { return mRenderWidth; }s
    int32_t getRenderHeight() { return mRenderHeight; }
    int32_t getScreenWidth() { return mScreenWidth; }
    int32_t getScreenHeight() { return mScreenHeight; }
    GLfloat* getProjectionMatrix() { return mProjectionMatrix[0]; }

...

Declare a new RenderVertex structure with four components - x, y, u, and v

Define the OpenGL resources necessary for the framebuffer, namely, the texture, the vertex buffer, the shader program, and its variables:

...
private:
    status initializeRenderBuffer...