Enable Camera Movement OpenGL RT Raytracer

I’m building the OpenGL ray-tracer at https://github.com/netpipe/OpenGL-Demos/tree/main/raytracer-engilas and need the classic WASD camera controls working. At the moment only the Escape key closes the window; nothing else moves the viewpoint.

What I suspect is missing is a proper view matrix (or equivalent camera logic) wired to keyboard input, but I’m open to whatever solution you find cleaner. The goal is straightforward: press W, A, S or D and see the camera move correspondingly inside the existing scene, with smooth, frame-rate-independent motion. mouse already works.

Please work directly in the current C++/OpenGL codebase, keep the external dependencies unchanged, and return:

• Updated source files with clear comments on the sections you touched