Memory leak in several examples

[sonicblue7real]

Platform: Linux
Ruby version: 3.0.2p107
Mittsu OpenGL Renderer 0.4.0

Running several examples like 02_geometries, 05_earth and 07_earth_normal showcases continuous memory increase.

[sonicblue7real]

I just discovered something interesting by accident, in the 05_earth example not adding the light_object into the scene but instead using a ambient light:
light2 = Mittsu::AmbientLight.new(0xffffff) ; scene.add(light2)
doesn't result in the same memory leak.

[sonicblue7real]

Unfortunately just adding a single obj file to a scene with that ambient light does again result in continuously increasing memory. From the GC.stats it looks like it's allocating more (total objects) than it's freeing.

[sonicblue7real]

Some new information after running more tests and looking at Ruby's memory usage: If even a single sphere is added to a basic scene, the memory issue persists (slowly leaking memory)... however, if I after X minutes remove that sphere from the scene (with scene.remove) the memory leak stops.

[sonicblue7real]

So I just discovered that even setting the visibility to false of the object at runtime stops the leak, making it again visible continues to leak memory.