function Creature(){

   this.x = 30;
   this.y = 50;
   this.colorRed=0;
   this.colorGreen=0;
   this.colorBlue=0;
   this.xspeed = 2;
   this.yspeed = 3;
   this.size = 20;
   this.status = 1;
   this.maxage = 500;
   this.currentAge = 0;
   this.id = "thisId";
   
   this.bouncex = function(){
       this.xspeed = -1 * this.xspeed;
   };
   this.bouncey = function(){
       this.yspeed = -1 * this.yspeed;
   };

   this.die = function(){ 

       this.status = 0;
       grid[this.x][this.y] = -1;
           
       this.xspeed = 0;
       this.yspeed = 0;
       this.size = 0;
       theDiv = document.getElementById(this.id);
       theDiv.style.backgroundColor = "white";
       theDiv.style.border = "0px";
           
   //        document.getElementById("environment")
     //                .removeChild(document.getElementById(this.id));


   }
   this.move = function (){
   	       this.currentAge++;
       if (this.currentAge > this.maxage){
          this.die();
       } else {
   	
   	       grid[this.x][this.y] = -1;
        
           this.x = this.x + this.xspeed;
           this.y = this.y + this.yspeed;
                                    
           if ((this.x + this.size) > maxWidth ){
               this.x = maxWidth - this.size;
               this.bouncex();
           } else if (this.x < 0) {
               this.x = 0;
               this.bouncex();
           } else if ((this.y + this.size) > maxHeight ){
               this.y = maxHeight - this.size;
               this.bouncey();             
           } else if (this.y < 0) {
               this.y = 0;
               this.bouncey();
           } 
                                    
                                       
           this.renderAt(this.x, this.y);
           this.checkForPartner();
       }                
   };

   this.renderAt = function(xpos, ypos){         
       theDiv = document.getElementById(this.id);
       theDiv.style.left = this.x;
       theDiv.style.top = this.y;
       
              grid[this.x][this.y] = this.gridIndex;
   };   
   
   this.createAt = function(idString, gridIdx, xpos, ypos, theSize, 
                            redLevel, greenLevel, blueLevel,
                            xspeedLevel, yspeedLevel){       
      
       this.id = idString;
       this.gridIndex = gridIdx;
       this.x = xpos;
       this.y = ypos;
       this.size = theSize;

       this.colorRed = redLevel;
       this.colorGreen = greenLevel;
       this.colorBlue = blueLevel;
        
       this.xspeed = xspeedLevel;
       this.yspeed = yspeedLevel;
        
       theDiv = document.createElement('div'); 
       theDiv.setAttribute('id',this.id);

       theEnv = document.getElementById("environment");
       theEnv.appendChild(theDiv);
        
       theDiv = document.getElementById(this.id);
       theDiv.style.position="absolute";       
       theDiv.style.left= this.x+"px";
       theDiv.style.top= this.y+"px";
       theDiv.style.border="2px solid red";
       theDiv.style.height=this.size;
       theDiv.style.width=this.size;
          
       theDiv.style.backgroundColor= 
                      "rgb("+this.colorRed+", "+this.colorGreen+"," 
                           +this.colorBlue+")";

       creatureList[this.gridIndex] = this;  
              grid[this.x][this.y] = this.gridIndex;        

   }
   this.breedWith = function(otherCreature){ 
   	
   	       if (elapsedTurns < 50){
           // do nothing
       } else {
           elapsedTurns = 0;        
   	   
           babyxspeed = this.getNewValue(this.xspeed, 
                              otherCreature.xspeed, -20, 20);
           babyyspeed = this.getNewValue(this.yspeed, 
                              otherCreature.yspeed, -20, 20);
           babysize = this.getNewValue(this.size, 
                              otherCreature.size, 0, 100);
           babycolorred = this.getNewValue(this.colorRed, 
                              otherCreature.colorRed, 0, 255);
           babycolorgreen = this.getNewValue(this.colorGreen, 
                              otherCreature.colorGreen, 0, 255);
           babycolorblue = this.getNewValue(this.colorBlue, 
                              otherCreature.colorBlue, 0, 255);

           baby = new Creature();
           
           index = creatureList.length;

           baby.createAt("index"+index, index, 
                          maxWidth/2, maxHeight/2, babysize, 
                          babycolorred, babycolorgreen, 
                          babycolorblue, babyxspeed, babyyspeed);   
                          
}                                                   

   }
   this.checkForPartner = function(){ 

       xmax = this.x+size;
       if (this.x+size > maxWidth){
           xmax = maxWidth;
       } 
        
       ymax = this.y+size;
       if (this.y+size > maxHeight){
          ymax = maxHeight;
       } 
        
       for(var xtocheck = this.x; xtocheck < xmax; xtocheck++) {
          for(var ytocheck = this.y; ytocheck < ymax; ytocheck++) {
              if (grid[xtocheck][ytocheck] != -1 &&
                  grid[xtocheck][ytocheck] != this.gridIndex){

                  this.breedWith(
                        creatureList[grid[xtocheck][ytocheck]]);
                  break;
              }
          }                
      }


   }
   
      this.getNewValue = function(old1, old2, min, max){
       if (old1 < old2){
          low = old1;
          high = old2;
       } else {
          low = old2;
          high = old1;
       }
          
       low = low - Math.round(low * .15);
       high = high + Math.round(high * .15);
          
       if (low < min){
          low = min;
       }
       if (high > max){
          high = max;
       }
          
       spread = high - low;
       offset = Math.round(Math.random()*spread);
       return low + offset;
   }
   

}