MIN_FPS < fps < MAX_FPS
0 < alpha < 1
0 < mb < 1
si fps > DEFAULT_FPS
    alpha < mb
sinon
    alpha > mb
fsi
mb = alpha + (fps - DEFAULT_FPS) / MAX_FPS
si fps = MAX_FPS
    mb = alpha + (MAX_FPS - DEFAULT_FPS) / MAX_FPS = 1 - DEFAULT_FPS / MAX_FPS
si fps = 0
    mb = alpha + (0 - DEFAULT_FPS) / MAX_FPS = 0 - DEFAULT_FPS / MAX_FPS
MAX_FPS = 200; DEFAULT_FPS = 50
si fps = MAX_FPS
    mb = alpha + 1 - 50 / 200 = alpha + 1 - 0.25 = alpha + 0.75
si fps = 0
    mb = alpha + (0 - 50) / 200 = alpha - 50 / 200 = alpha - 0.25
MAX_FPS = 100; DEFAULT_FPS = 50
si fps = MAX_FPS
    mb = alpha + 1 - 0.5 = alpha + 0.5
si fps = 0
    mb = alpha - 0.5
MAX_FPS = 50; DEFAULT_FPS = 50
si fps = MAX_FPS
    mb = alpha
si fps = 0
    mb = alpha - 1

