topical media & game development

topical media & game development

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game-xna-intro-XnaGraphicEngineChapter6-Game-FpsCounter.cs / cs


  #region Using directives
  using System;
  using System.Collections.Generic;
  using System.Text;
  using Microsoft.Xna.Framework;
  using XnaGraphicEngine.Helpers;
  using Microsoft.Xna.Framework.Input;
  using XnaGraphicEngine.Graphics;
  #endregion
  
  namespace XnaGraphicEngine.Game
  {

<summary> Simple FPS (Frames per second) counter component, which displays the current fps in the upper left corner. </summary> class FpsCounter : DrawableGameComponent { #region Variables <summary> Elapsed time this frame in ms. Always have something valid here in case we devide through this values! </summary> private static float elapsedTimeThisFrameInMs = 0.001f, totalTimeMs = 0;

<summary> Helper for calculating frames per second. </summary> private static float startTimeThisSecond = 0;

<summary> For more accurate frames per second calculations, just count for one second, then fpsLastSecond is updated. Btw: Start with 1 to help some tests avoid the devide through zero problem. </summary> private static int frameCountThisSecond = 0, totalFrameCount = 0, fpsLastSecond = 60;

<summary> Interpolated fps over the last 10 seconds. Obviously goes down if our framerate is low. </summary> private static float fpsInterpolated = 100.0f;

<summary> Fps </summary> <returns>Int</returns> public static int Fps { get { return fpsLastSecond; } // get } // Fps #endregion #region Constructor public FpsCounter(BaseGame game) : base(game) { } // FpsCounter(game) #endregion


                  #region Update

<summary> Update </summary> <param name="gameTime">Game time</param> public override void Update(GameTime gameTime) { base.Update(gameTime);


                          elapsedTimeThisFrameInMs =
                                  (float)gameTime.ElapsedRealTime.TotalMilliseconds;
                          totalTimeMs += elapsedTimeThisFrameInMs;
  
                          // Make sure elapsedTimeThisFrameInMs is never 0
                          if (elapsedTimeThisFrameInMs <= 0)
                                  elapsedTimeThisFrameInMs = 0.001f;
  
                          // Increase frame counter for FramesPerSecond
                          frameCountThisSecond++;
                          totalFrameCount++;
  
                          // One second elapsed?
                          if (totalTimeMs - startTimeThisSecond > 1000.0f)
                          {
                                  // Calc fps
                                  fpsLastSecond = (int)(frameCountThisSecond * 1000.0f /
                                          (totalTimeMs - startTimeThisSecond));
                                  if (fpsLastSecond <= 0)
                                          fpsLastSecond = 1;
                                  // Reset startSecondTick and repaintCountSecond
                                  startTimeThisSecond = totalTimeMs;
                                  frameCountThisSecond = 0;
  
                                  fpsInterpolated =
                                          MathHelper.Lerp(fpsInterpolated, fpsLastSecond, 0.1f);
                          } // if (Math.Abs)
  
                          // Restore depth buffer, else 3D rendering will be messed up.
                          BaseGame.Device.RenderState.DepthBufferEnable = true;
                  } // Update(gameTime)
                  #endregion
  
                  #region Draw
                  bool showFps =
  if DEBUG
                          true;
  else
                          false;
  endif

<summary> Draw </summary> <param name="gameTime">Game time</param> public override void Draw(GameTime gameTime) { base.Draw(gameTime);


                          // Show fps (use F1 or left shoulder+y button on gamepad to toggle)
                          if (Input.KeyboardF1JustPressed ||
                                  // Also allow toggeling with gamepad
                                  (Input.GamePad.Buttons.LeftShoulder == ButtonState.Pressed &&
                                  Input.GamePadYJustPressed))
                                  showFps = !showFps;
  if XBOX360
                          if (showFps)
                                  TextureFont.WriteText(BaseGame.XToRes(32), BaseGame.YToRes(26),
                                          "Fps: " + Fps);
  else
                          if (showFps)
                                  TextureFont.WriteText(2, 2, "Fps: " + Fps);
  endif
                  } // Draw(gameTime)
                  #endregion
          } // class FpsCounter
  } // namespace XnaGraphicEngine.Game

[] readme course(s) preface I 1 2 II 3 4 III 5 6 7 IV 8 9 10 V 11 12 afterthought(s) appendix reference(s) example(s) resource(s) _

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