Optimizing Game Performance - Developing Games With Ruby - page 66

The game still doesn't feel fast enough, FPS occasionally keeps dropping down to ~45, so
we will have to do profile our code in smarter way.
Advanced Profiling Techniques
We would get more accuracy when profiling only what we want to optimize. In our case it
is everything that happens in PlayState , except for Map generation. This time we will
have to use ruby-prof API to hook into places we need.
Map generation happens in PlayState initializer, so we will leverage
GameState#enter and GameState#leave to start and stop profiling, since it
happens after state is initialized. Here is how we hook in:
require 'ruby-prof'
class PlayState < GameState
# ...
def enter
RubyProf . start
end
def leave
result = RubyProf . stop
printer = RubyProf :: FlatPrinter . new(result)
printer . print( STDOUT )
end
# ...
end
Then we run the game as usual:
$ ruby 04-prototype-optimized/main.rb
Now, after we press N to start new game, Map generation happens relatively fast, and then
profiling kicks in, FPS drops to 15. After moving around and shooting for a while we hit
Esc to return to the menu, and at that point PlayState#leave spits profiling results
out to the console: