Add Timer, add audio queuing, and make Window return current dimensions

samples/queue_audio.cr

@@ -0,0 +1,40 @@
+require "../src/sdl"
+
+CHANNELS    =     1
+BUFFER_SIZE =  4096
+SAMPLE_RATE = 44100
+
+SDL.init(SDL::Init::AUDIO)
+at_exit { SDL.quit }
+
+audiospec = LibSDL::AudioSpec.new
+audiospec.freq = SAMPLE_RATE
+audiospec.format = LibSDL::AUDIO_F32SYS
+audiospec.channels = CHANNELS
+audiospec.samples = BUFFER_SIZE
+audiospec.callback = nil
+audiospec.userdata = nil
+
+obtained_spec = LibSDL::AudioSpec.new
+
+raise "Failed to open audio" if LibSDL.open_audio(pointerof(audiospec), pointerof(obtained_spec)) > 0
+
+LibSDL.pause_audio 0
+
+amp = 0.25
+freq = 500
+time = 0.0
+delta_time = 1 / SAMPLE_RATE
+buffer = Slice(Float32).new BUFFER_SIZE
+
+loop do
+  BUFFER_SIZE.times do |sample| # fill buffer with simple sine wave
+    value = amp * Math.sin(2 * Math::PI * freq * time)
+    buffer[sample] = value.to_f32
+    time += delta_time
+  end
+  while LibSDL.get_queued_audio_size(1) > BUFFER_SIZE * sizeof(Float32) * 2 # delay until we need more buffered audio
+    LibSDL.delay(1)
+  end
+  LibSDL.queue_audio(1, buffer, BUFFER_SIZE * sizeof(Float32))
+end

src/lib_sdl/audio.cr

@@ -116,4 +116,9 @@ lib LibSDL
 
   fun close_audio = SDL_CloseAudio
   fun close_audio = SDL_CloseAudioDevice(dev : AudioDeviceID)
+
+  fun queue_audio = SDL_QueueAudio(dev : AudioDeviceID, data : Void*, len : UInt32) : Int
+  fun dequeue_audio = SDL_DequeueAudio(dev : AudioDeviceID, data : Void*, len : UInt32) : UInt32
+  fun get_queued_audio_size = SDL_GetQueuedAudioSize(dev : AudioDeviceID) : UInt32
+  fun clear_queued_audio = SDL_ClearQueuedAudio(dev : AudioDeviceID)
 end

src/window.cr

@@ -5,20 +5,31 @@ module SDL
     alias Flags = LibSDL::WindowFlags
     alias Position = LibSDL::WindowPosition
 
-    getter width : Int32
-    getter height : Int32
-
-    def initialize(title, @width, @height,
+    def initialize(title, width, height,
                    x : Position = Position::UNDEFINED,
                    y : Position = Position::UNDEFINED,
                    flags : Flags = Flags::SHOWN)
-      @window = LibSDL.create_window(title, x, y, @width, @height, flags)
+      @window = LibSDL.create_window(title, x, y, width, height, flags)
     end
 
     def finalize
       LibSDL.destroy_window(self)
     end
 
+    # Get the window's current width and height
+    def size : Tuple(Int32, Int32)
+      LibSDL.get_window_size(@window, out w, out h)
+      {w, h}
+    end
+
+    def width : Int32
+      size[0]
+    end
+
+    def height : Int32
+      size[1]
+    end
+
     def surface
       @surface ||= begin
         surface = LibSDL.get_window_surface(self)
@@ -71,8 +82,8 @@ module SDL
     {% end %}
 
     enum Fullscreen
-      WINDOW = 0
-      FULLSCREEN = LibSDL::WindowFlags::FULLSCREEN
+      WINDOW             = 0
+      FULLSCREEN         = LibSDL::WindowFlags::FULLSCREEN
       FULLSCREEN_DESKTOP = LibSDL::WindowFlags::FULLSCREEN_DESKTOP
     end