//
// Random3dText_w_depth.jsx
//
//Byron Nash 01/05
//The text reading/creating was borrowed from createTextLayersFromFile.jsx
// by Dan Ebberts
//
// This script reads a user specified text file and
// creates a text layer for each line of text in a 
// new comp called "Text Comp", or it uses the active comp.
// - adds expression to control a random placement in 3d space
// - adds expression to control a depth fade as the layer recedes from the camera
// - creates a new camera and a null with sliders to control the effect
{

  // create undo group

  app.beginUndoGroup("Create Text Layers From File");

  // Prompt user to select text file

  var myFile = fileGetDialog("Select a text file to open.", "TEXT txt");
  if (myFile != null){

    // open file
    var fileOK = myFile.open("r","TEXT","????");
    if (fileOK){

      // create project if necessary

      var proj = app.project;
      if(!proj) proj = app.newProject();
      
		//set currently selected comp to variable
        var myComp = app.project.activeItem; 

		//check to see if selected item is a comp, if not, make a new comp      
        if(proj.activeItem instanceof CompItem) {
        	var myComp = proj.activeItem;
        	}else{
      // create new comp named 'my text comp'
      var compW = 720; // comp width
      var compH = 486; // comp height
      var compL = 15;  // comp length (seconds)
      var compRate = 29.97; // comp frame rate
      var compBG = [0/255,0/255,0/255] // comp background color
  
      var myItemCollection = app.project.items;
      var myComp = myItemCollection.addComp('Text Comp',compW,compH,1,compL,compRate);
      myComp.bgColor = compBG;
		}
		
		//setup controller null and add expression sliders
    	var controlLayer = myComp.layers.addNull();
    	controlLayer.startTime = 0;
    	controlLayer.enabled = false;
    	controlLayer.source.name = "Controller";
    	var theControl = controlLayer.Effects.addProperty("ADBE Slider Control");
    	theControl.name = "Spread";
    	theControl.property(1).setValue(0);
    	var opacityMin = controlLayer.Effects.addProperty("ADBE Slider Control");
    	opacityMin.name = "Start Fade";
    	opacityMin.property(1).setValue(0);
        var opacityMax = controlLayer.Effects.addProperty("ADBE Slider Control");
    	opacityMax.name = "End Fade";
    	opacityMax.property(1).setValue(1000);
    	  
      	var cam = myComp.layers.addCamera("Camera 1",[360,243]);//make a new camera
      // read text lines and create text layer for each
      // until end-of-file is reached

      var text;
      while (!myFile.eof){
        text = myFile.readln();
        if (text != "") {
        var curLayer = myComp.layers.addText(text);
        curLayer.threeDLayer = true;
        //define expressions on position and opacity
    	var posExp = 'seedRandom(index,true);\r'+ 
            		'slider = thisComp.layer("Controller").effect("Spread")("Slider");\r'+
                	'midWidth = thisComp.width/2; midHeight = thisComp.height/2;\r'+
                    'x = random(slider,slider*-1);\r'+
                    'y = random(slider,slider*-1);\r'+
                    'z = random(slider,slider*-1);\r'+
                    '[x+midWidth,y+midHeight,z];\r';
        var opacExp = 'depth = length(position,thisComp.layer("Camera 1").position);\r'+
                      'min = thisComp.layer("Controller").effect("Start Fade")("Slider");\r'+
                      'max = thisComp.layer("Controller").effect("End Fade")("Slider");\r'+
                      'linear(depth,min,max,100,0)';
     	//add expressions on position and opacity
     	curLayer.property("position").expression = posExp;
    	curLayer.property("opacity").expression = opacExp;
		}      
      }
 
 controlLayer.moveToBeginning();//moves the null to the top of the stack
 cam.moveToBeginning();//moves the cam to the top of the stack
      // close the file before exiting

      myFile.close();

    }else{
      alert("File open failed!");
    }
 
  }else{
    alert("No text file selected.");
  }

  app.endUndoGroup();
}