Introduction
Downloads
Documentation
Tutorials
Pixie Lite
Forum

Home

SpriteAction_AlphaSine.cpp

Go to the documentation of this file.

//*** SpriteAction_AlphaSine.cpp ***
 
#include "SpriteAction_AlphaSine.h"
#include "ColorHelper.h"
#include "Sprite.h"
#include "SpriteController.h"


//*** Constructor ***

SpriteAction_AlphaSine::SpriteAction_AlphaSine(float amplitude, float offset, float frequency, float easeIn):
   amplitude_(amplitude),
   offset_(offset),
   frequency_(frequency),
   easeIn_(easeIn),
   perpetual_(true),
   time_(0),
   easeOut_(0),
   elapsedTime_(0)
   {
   }


//*** Constructor ***

SpriteAction_AlphaSine::SpriteAction_AlphaSine(float amplitude, float offset, float frequency, float time, float easeIn, float easeOut):
   amplitude_(amplitude),
   offset_(offset),
   frequency_(frequency),
   easeIn_(easeIn),
   perpetual_(false),
   time_(time),
   easeOut_(easeOut),
   elapsedTime_(0)
   {
   }


//*** Setup ***

void SpriteAction_AlphaSine::Setup(SpriteController* controller, Sprite* sprite)
   {
   if (time_==0)
      {
      perpetual_=true;
      }
   }


//*** Update ***

void SpriteAction_AlphaSine::Update(SpriteController* controller, Sprite* sprite, float deltaTime)
   {
   elapsedTime_+=deltaTime;
   
   if (!perpetual_ && elapsedTime_>time_)
      {  
      ActionCompleted();
      return;
      }

   float scale=1.0f;
   if (elapsedTime_<easeIn_)
      {
      scale=elapsedTime_/easeIn_;
      }
   else if (!perpetual_ && elapsedTime_>time_-easeOut_)
      {
      scale=1.0f-(elapsedTime_-(time_-easeOut_))/easeOut_;
      }

   float sine=Sin(elapsedTime_*frequency_+ToRadians(offset_))*amplitude_*scale;
   sine=(sine+1.0f)*0.5f;
   
   int alpha=Clamp((int)(sine*255.0f),1,255);   
   sprite->SetAlpha((char)alpha);
   }

---

Pixie University and the Pixie Game Engine is created and managed by Mattias Gustavsson.
Reproduction/republishing of any material on this site without permission is strictly prohibited.