Adding in Timer

samples/22_timing.cr

@@ -0,0 +1,38 @@
+require "../src/sdl"
+require "../src/image"
+require "../src/ttf"
+
+SDL.init(SDL::Init::VIDEO); at_exit { SDL.quit }
+SDL::TTF.init; at_exit { SDL::TTF.quit }
+
+window = SDL::Window.new("SDL tutorial", 640, 480)
+renderer = SDL::Renderer.new(window, SDL::Renderer::Flags::ACCELERATED | SDL::Renderer::Flags::PRESENTVSYNC)
+
+font = SDL::TTF::Font.new(File.join(__DIR__, "data", "lazy.ttf"), 28)
+font_color = SDL::Color[0, 0, 0, 255]
+
+renderer.draw_color = SDL::Color[255, 255, 255, 255]
+prompt_surface = font.render_shaded("Press Enter to Reset Start Time.", font_color, renderer.draw_color)
+
+start_time = 0
+
+loop do
+  case event = SDL::Event.poll
+  when SDL::Event::Quit
+    break
+  when SDL::Event::Keyboard
+    if event.keydown? && event.sym.return?
+      start_time = SDL::Timer.ticks
+    end
+  end
+  renderer.clear
+  prompt_x = (window.width - prompt_surface.width) / 2
+  renderer.copy(prompt_surface, dstrect: SDL::Rect[prompt_x, 0, prompt_surface.width, prompt_surface.height])
+
+  time_text_surface = font.render_shaded("Milliseconds since start time #{SDL::Timer.ticks - start_time}", font_color, renderer.draw_color)
+  time_text_x = (window.width - time_text_surface.width) / 2
+  time_text_y = (window.height - time_text_surface.height) / 2
+  renderer.copy(time_text_surface, dstrect: SDL::Rect[time_text_x, time_text_y, time_text_surface.width, time_text_surface.height])
+
+  renderer.present
+end

samples/23_advanced_timers.cr

@@ -0,0 +1,117 @@
+require "../src/sdl"
+require "../src/image"
+require "../src/ttf"
+
+SDL.init(SDL::Init::VIDEO); at_exit { SDL.quit }
+SDL::TTF.init; at_exit { SDL::TTF.quit }
+
+window = SDL::Window.new("SDL tutorial", 640, 480)
+renderer = SDL::Renderer.new(window, SDL::Renderer::Flags::ACCELERATED | SDL::Renderer::Flags::PRESENTVSYNC)
+
+font = SDL::TTF::Font.new(File.join(__DIR__, "data", "lazy.ttf"), 28)
+font_color = SDL::Color[0, 0, 0, 255]
+
+renderer.draw_color = SDL::Color[255, 255, 255, 255]
+bg_color = renderer.draw_color
+start_prompt_surface = font.render_shaded("Press S to Start or Stop the Timer", font_color, bg_color)
+pause_prompt_surface = font.render_shaded("Press P to Pause or Unpause the Timer", font_color, bg_color)
+
+class SampleTimer
+  property started : Bool = false
+  property paused : Bool = false
+  property start_ticks : UInt32 = 0_u32
+  property paused_ticks : UInt32 = 0_u32
+
+  def ticks
+    time = 0
+    if started?
+      if paused?
+        time = @paused_ticks
+      else
+        time = SDL::Timer.ticks - @start_ticks
+      end
+    end
+    time
+  end
+
+  def start
+    @started = true
+    @paused = false
+    @start_ticks = SDL::Timer.ticks
+    @paused_ticks = 0_u32
+  end
+
+  def stop
+    @started = false
+    @paused = false
+    @start_ticks = 0_u32
+    @paused_ticks = 0_u32
+  end
+
+  def started?
+    @started
+  end
+
+  def toggle_on_state
+    started? ? stop : start
+  end
+
+  def pause
+    unless paused?
+      @paused = true
+      @paused_ticks = SDL::Timer.ticks - @start_ticks
+      @start_ticks = 0_u32
+    end
+  end
+
+  def unpause
+    if paused?
+      @paused = false
+      @start_ticks = SDL::Timer.ticks - @paused_ticks
+      @paused_ticks = 0_u32
+    end
+  end
+
+  def paused?
+    @paused && @started
+  end
+
+  def toggle_pause_state
+    paused? ? unpause : pause
+  end
+end
+
+timer = SampleTimer.new
+
+loop do
+  case event = SDL::Event.poll
+  when SDL::Event::Quit
+    break
+  when SDL::Event::Keyboard
+    if event.keydown?
+      case event.sym
+      when .s?
+        timer.toggle_on_state
+      when .p?
+        timer.toggle_pause_state
+      end
+    end
+  end
+  renderer.clear
+  # Render the start prompt text
+  start_prompt_x = (window.width - start_prompt_surface.width) / 2
+  renderer.copy(start_prompt_surface, dstrect: SDL::Rect[start_prompt_x, 0, start_prompt_surface.width, start_prompt_surface.height])
+
+  # Render the pause prompt text
+  pause_prompt_x = (window.width - pause_prompt_surface.width) / 2
+  renderer.copy(pause_prompt_surface, dstrect: SDL::Rect[pause_prompt_x, start_prompt_surface.height, pause_prompt_surface.width, pause_prompt_surface.height])
+
+  # Render the action text
+  time_text_surface = font.render_shaded("Seconds since start time #{timer.ticks / 1000.0}", font_color, bg_color)
+  time_text_x = (window.width - time_text_surface.width) / 2
+  time_text_y = (window.height - time_text_surface.height) / 2
+  renderer.copy(time_text_surface, dstrect: SDL::Rect[time_text_x, time_text_y, time_text_surface.width, time_text_surface.height])
+
+  renderer.present
+end
+

src/lib_sdl.cr

@@ -16,6 +16,7 @@ require "./lib_sdl/render"
 require "./lib_sdl/rwops"
 require "./lib_sdl/shape"
 #require "./lib_sdl/system"
+require "./lib_sdl/timer"
 require "./lib_sdl/video"
 
 @[Link("SDL2")]

src/lib_sdl/timer.cr

@@ -0,0 +1,13 @@
+lib LibSDL
+  # (interval, params)
+  alias TimerCallback = (UInt32, Void*) -> Void
+  alias TimerID = LibC::Int
+
+  fun add_timer = SDL_AddTimer(interval : UInt32, callback : TimerCallback, param : Void*) : TimerID
+  fun delay = SDL_Delay(ms : UInt32) : Void
+  fun get_performance_counter = SDL_GetPerformanceCounter() : UInt64
+  fun get_performance_frequency = SDL_GetPerformanceFrequency() : UInt64
+  fun get_ticks = SDL_GetTicks() : UInt32
+  fun remove_timer = SDL_RemoveTimer(id : TimerID) : Bool
+  fun ticks_passed = SDL_TICKS_PASSED(a : UInt32, b : UInt32) : Bool
+end

src/sdl.cr

@@ -21,6 +21,7 @@ require "./renderer"
 require "./window"
 require "./screensaver"
 require "./color"
+require "./timer"
 
 module SDL
   class Error < Exception

src/timer.cr

@@ -0,0 +1,28 @@
+module SDL
+  module Timer
+
+    def self.add(interval, &callback : UInt32 -> Void)
+      LibSDL.add_timer(interval, callback)
+    end
+
+    def self.delay(ms : UInt32)
+      LibSDL.delay(ms)
+    end
+
+    def self.performance_counter
+      LibSDL.get_performance_counter
+    end
+
+    def self.performance_frequency
+      LibSDL.get_performance_frequency
+    end
+
+    def self.ticks
+      LibSDL.get_ticks
+    end
+
+    def self.remove(timer_id)
+      LibSDL.remove_timer(timer_id)
+    end
+  end
+end