File: fpstimer.rb

package info (click to toggle)
ruby-sdl 2.1.3-1
  • links: PTS, VCS
  • area: main
  • in suites: jessie, jessie-kfreebsd
  • size: 4,344 kB
  • ctags: 4,200
  • sloc: cpp: 7,598; ansic: 4,475; ruby: 2,258; sh: 102; makefile: 97
file content (175 lines) | stat: -rw-r--r-- 3,232 bytes parent folder | download | duplicates (4)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
require 'sdl'

class FPSTimerSample
  FPS_COUNT = 10

  attr_accessor :fps
  attr_reader :real_fps, :total_skip
  attr_reader :count_sleep
  # +fps+ is the number of frames per second that you want to keep,
  # +accurary+ is the accurary of sleep/SDL.delay in milisecond
  def initialize(fps = 60, accurary = 10, skip_limit = 15)
    @fps = fps
    @accurary = accurary / 1000.0
    @skip_limit = skip_limit
  end

  # reset timer, you should call just before starting loop
  def reset
    @old = get_ticks
    @skip = 0
    @real_fps = @fps
    @frame_count = 0
    @fps_old = @old
    @count_sleep = 0
    @total_skip = 0
  end

  # execute given block and wait
  def wait_frame
    now = get_ticks
    nxt = @old + (1.0/@fps)
    if nxt > now || @skip > @skip_limit
      yield
      @skip = 0
      wait(nxt)
      @old = nxt
    else
      @skip += 1
      @total_skip += 1
      @old = get_ticks
    end

    calc_real_fps
  end

  private
  def wait(nxt)
    while nxt > get_ticks + @accurary
      sleep(@accurary - 0.005)
      @count_sleep += 1
    end

    while nxt > get_ticks
      # busy loop, do nothing
    end
  end

  def get_ticks
    SDL.get_ticks / 1000.0
  end

  def calc_real_fps
    @frame_count += 1
    if @frame_count >= FPS_COUNT
      @frame_count = 0
      now = get_ticks
      @real_fps = FPS_COUNT / (now - @fps_old)
      @fps_old = now
    end
  end
end

class FPSTimerLight
  N = 12
  DT = 2
  FPS_COUNT = 10
  
  attr_reader :fps
  attr_reader :real_fps
  # +fps+ is the number of frames per second that you want to keep,
  # +accurary+ is the accurary of sleep/SDL.delay in milisecond
  def initialize(fps = 60, accurary = 10, skip_limit = 15)
    @fps = fps
    @accurary = accurary * N
    @skip_limit = 15
    @one_frame = 1000*N / fps
    @delay = accurary - 2
  end
  
  # reset timer, you should call just before starting loop
  def reset
    @old = get_ticks
    @skip = 0
    
    # for calculate real fps
    @frame_count = 0
    @fps_old = @old
    @real_fps = @fps
  end

  def wait_frame
    now = get_ticks
    nxt = @old + @one_frame
    if nxt > now || @skip > @skip_limit
      yield
      @skip = 0
      wait(nxt)
      @old = nxt
    else
      @skip += 1
      @total_skip += 1
      @old = get_ticks
    end

    calc_real_fps
  end

  private
  def get_ticks
    SDL.get_ticks * N
  end
  
  def wait(nxt)
    while nxt > get_ticks + @accurary
      SDL.delay(@delay) 
    end

    while nxt > get_ticks
      # busy loop, do nothing
    end
  end

  def calc_real_fps
    @frame_count += 1
    if @frame_count >= FPS_COUNT
      @frame_count = 0
      now = get_ticks
      @real_fps = (N*1000*FPS_COUNT)/(now - @fps_old)
      @fps_old = now
    end
  end
end
  
if __FILE__ == $0
  timer = FPSTimerSample.new
  log = []
  
  timer.reset
  300.times do
    sleep 0.005 if rand(5) == 0
    timer.wait_frame do
      log << timer.real_fps.to_s
    end
  end
  
  puts log
  printf "skip:%d\n", timer.total_skip
  printf "sleep:%d\n", timer.count_sleep

  puts
  
  timer = FPSTimerLight.new
  log = []
  
  timer.reset
  old = SDL.get_ticks
  300.times do
    sleep 0.005 if rand(5) == 0
    timer.wait_frame do
      log << timer.real_fps
    end
  end

  puts log
end