# src/pixi/renderers/WebGLBatch.js - Pixi.JS

#

API Docs for: 1.0.0
Show: Inherited Protected Private Deprecated

# File: src/pixi/renderers/WebGLBatch.js

    /**
     * @author Mat Groves http://matgroves.com/ @Doormat23
     */

    PIXI._batchs = [];

    /**
     * @private
     */
    PIXI._getBatch = function(gl)
    {
    	if(PIXI._batchs.length == 0)
    	{
    		return new PIXI.WebGLBatch(gl);
    	}
    	else
    	{
    		return PIXI._batchs.pop();
    	}
    }

    /**
     * @private
     */
    PIXI._returnBatch = function(batch)
    {
    	batch.clean();
    	PIXI._batchs.push(batch);
    }

    /**
     * @private
     */
    PIXI._restoreBatchs = function(gl)
    {
    	for (var i=0; i < PIXI._batchs.length; i++)
    	{
    	  PIXI._batchs[i].restoreLostContext(gl);
    	};
    }

    /**
     * A WebGLBatch Enables a group of sprites to be drawn using the same settings.
     * if a group of sprites all have the same baseTexture and blendMode then they can be grouped into a batch. All the sprites in a batch can then be drawn in one go by the GPU which is hugely efficient. ALL sprites in the webGL renderer are added to a batch even if the batch only contains one sprite. Batching is handled automatically by the webGL renderer. A good tip is: the smaller the number of batchs there are, the faster the webGL renderer will run.
     * @class WebGLBatch
     * @param an instance of the webGL context
     * @return {PIXI.renderers.WebGLBatch} WebGLBatch {@link PIXI.renderers.WebGLBatch}
     */
    PIXI.WebGLBatch = function(gl)
    {
    	this.gl = gl;

    	this.size = 0;

    	this.vertexBuffer =  gl.createBuffer();
    	this.indexBuffer =  gl.createBuffer();
    	this.uvBuffer =  gl.createBuffer();
    	this.colorBuffer =  gl.createBuffer();
    	this.blendMode = PIXI.blendModes.NORMAL;
    	this.dynamicSize = 1;
    }

    // constructor
    PIXI.WebGLBatch.constructor = PIXI.WebGLBatch;

    /**
     * Cleans the batch so that is can be returned to an object pool and reused
     */
    PIXI.WebGLBatch.prototype.clean = function()
    {
    	this.verticies = [];
    	this.uvs = [];
    	this.indices = [];
    	this.colors = [];
    	//this.sprites = [];
    	this.dynamicSize = 1;
    	this.texture = null;
    	this.last = null;
    	this.size = 0;

    	this.head;
    	this.tail;
    }

    /*
     * recreates the buffers in the event of a context loss
     */
    PIXI.WebGLBatch.prototype.restoreLostContext = function(gl)
    {
    	this.gl = gl;
    	this.vertexBuffer =  gl.createBuffer();
    	this.indexBuffer =  gl.createBuffer();
    	this.uvBuffer =  gl.createBuffer();
    	this.colorBuffer =  gl.createBuffer();
    }

    /**
     * inits the batch's texture and blend mode based if the supplied sprite
     * @method init
     * @param sprite {Sprite} the first sprite to be added to the batch. Only sprites with the same base texture and blend mode will be allowed to be added to this batch
     */
    PIXI.WebGLBatch.prototype.init = function(sprite)
    {
    	sprite.batch = this;
    	this.dirty = true;
    	this.blendMode = sprite.blendMode;
    	this.texture = sprite.texture.baseTexture;
    //	this.sprites.push(sprite);
    	this.head = sprite;
    	this.tail = sprite;
    	this.size = 1;

    	this.growBatch();
    }

    /**
     * inserts a sprite before the specified sprite
     * @method insertBefore
     * @param sprite {Sprite} the sprite to be added
     * @param nextSprite {nextSprite} the first sprite will be inserted before this sprite
     */
    PIXI.WebGLBatch.prototype.insertBefore = function(sprite, nextSprite)
    {
    	this.size++;

    	sprite.batch = this;
    	this.dirty = true;
    	var tempPrev = nextSprite.__prev;
    	nextSprite.__prev = sprite;
    	sprite.__next = nextSprite;

    	if(tempPrev)
    	{
    		sprite.__prev = tempPrev;
    		tempPrev.__next = sprite;
    	}
    	else
    	{
    		this.head = sprite;
    		//this.head.__prev = null
    	}
    }

    /**
     * inserts a sprite after the specified sprite
     * @method insertAfter
     * @param sprite {Sprite} the sprite to be added
     * @param  previousSprite {Sprite} the first sprite will be inserted after this sprite
     */
    PIXI.WebGLBatch.prototype.insertAfter = function(sprite, previousSprite)
    {
    	this.size++;

    	sprite.batch = this;
    	this.dirty = true;

    	var tempNext = previousSprite.__next;
    	previousSprite.__next = sprite;
    	sprite.__prev = previousSprite;

    	if(tempNext)
    	{
    		sprite.__next = tempNext;
    		tempNext.__prev = sprite;
    	}
    	else
    	{
    		this.tail = sprite
    	}

    }

    /**
     * removes a sprite from the batch
     * @method remove
     * @param sprite {Sprite} the sprite to be removed
     */
    PIXI.WebGLBatch.prototype.remove = function(sprite)
    {
    	this.size--;

    	if(this.size == 0)
    	{
    		sprite.batch = null;
    		sprite.__prev = null;
    		sprite.__next = null;
    		return;
    	}

    	if(sprite.__prev)
    	{
    		sprite.__prev.__next = sprite.__next;
    	}
    	else
    	{
    		this.head = sprite.__next;
    		this.head.__prev = null;
    	}

    	if(sprite.__next)
    	{
    		sprite.__next.__prev = sprite.__prev;
    	}
    	else
    	{
    		this.tail = sprite.__prev;
    		this.tail.__next = null
    	}

    	sprite.batch = null;
    	sprite.__next = null;
    	sprite.__prev = null;
    	this.dirty = true;
    }

    /**
     * Splits the batch into two with the specified sprite being the start of the new batch.
     * @method split
     * @param sprite {Sprite} the sprite that indicates where the batch should be split
     * @return {WebGLBatch} the new batch
     */
    PIXI.WebGLBatch.prototype.split = function(sprite)
    {

    	//console.log("Splitting batch :" + this.size)
    //	console.log(sprite)
    //	console.log("-------")
    	this.dirty = true;

    	//var val = (this.tail == this.head)
    	//console.log(val + " SAME?");
    	var batch = new PIXI.WebGLBatch(this.gl)//PIXI._getBatch(this.gl);
    	batch.init(sprite);
    	batch.tail = this.tail;
    	//console.log("id is " +batcheee.id)

    	this.tail = sprite.__prev;
    	this.tail.__next = null;

    	sprite.__prev = null;
    	// return a splite batch!
    	//sprite.__prev.__next = null;
    	//sprite.__prev = null;

    	// TODO this size is wrong!
    	// need to recalculate :/ problem with a linked list!
    	// unless it gets calculated in the "clean"?

    	// need to loop through items as there is no way to know the length on a linked list :/
    	var tempSize = 0;
    	while(sprite)
    	{
    		tempSize++;
    		sprite.batch = batch;
    		sprite = sprite.__next;
    	}

    	batch.size = tempSize;
    	this.size -= tempSize;

    	return batch;
    }

    /**
     * Merges two batchs together
     * @method merge
     * @param batch {WebGLBatch} the batch that will be merged
     */
    PIXI.WebGLBatch.prototype.merge = function(batch)
    {
    	this.dirty = true;

    	this.tail.__next = batch.head;
    	batch.head.__prev = this.tail;

    	this.size += batch.size;

    	this.tail = batch.tail;

    	var sprite = batch.head;
    	while(sprite)
    	{
    		sprite.batch = this;
    		sprite = sprite.__next;
    	}

    }

    /**
     * Grows the size of the batch. As the elements in the batch cannot have a dynamic size this function is used to increase the size of the batch. It also creates a little extra room so that the batch does not need to be resized every time a sprite is added
     * @methos growBatch
     */
    PIXI.WebGLBatch.prototype.growBatch = function()
    {
    	var gl = this.gl;
    	if( this.size == 1)
    	{
    		this.dynamicSize = 1;
    	}
    	else
    	{
    		this.dynamicSize = this.size * 1.5
    	}
    	// grow verts
    	this.verticies = new Float32Array(this.dynamicSize * 8);

    	gl.bindBuffer(gl.ARRAY_BUFFER, this.vertexBuffer);
    	gl.bufferData(gl.ARRAY_BUFFER,this.verticies , gl.DYNAMIC_DRAW);

    	this.uvs  = new Float32Array( this.dynamicSize * 8 )
    	gl.bindBuffer(gl.ARRAY_BUFFER, this.uvBuffer);
    	gl.bufferData(gl.ARRAY_BUFFER, this.uvs , gl.DYNAMIC_DRAW);

    	this.dirtyUVS = true;

    	this.colors  = new Float32Array( this.dynamicSize * 4 )
    	gl.bindBuffer(gl.ARRAY_BUFFER, this.colorBuffer);
    	gl.bufferData(gl.ARRAY_BUFFER, this.colors , gl.DYNAMIC_DRAW);

    	this.dirtyColors = true;

    	this.indices = new Uint16Array(this.dynamicSize * 6);
    	var length = this.indices.length/6;

    	for (var i=0; i < length; i++)
    	{
    	    var index2 = i * 6;
    	    var index3 = i * 4;
    		this.indices[index2 + 0] = index3 + 0;
    		this.indices[index2 + 1] = index3 + 1;
    		this.indices[index2 + 2] = index3 + 2;
    		this.indices[index2 + 3] = index3 + 0;
    		this.indices[index2 + 4] = index3 + 2;
    		this.indices[index2 + 5] = index3 + 3;
    	};

    	gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, this.indexBuffer);
        gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, this.indices, gl.STATIC_DRAW);

    }

    /**
     * Refresh's all the data in the batch and sync's it with the webGL buffers
     * @method refresh
     */
    PIXI.WebGLBatch.prototype.refresh = function()
    {
    	var gl = this.gl;

    	if (this.dynamicSize < this.size)
    	{
    		this.growBatch();
    	}

    	var indexRun = 0;
    	var worldTransform, width, height, aX, aY, w0, w1, h0, h1, index
    	var a, b, c, d, tx, ty

    	var displayObject = this.head

    	while(displayObject)
    	{
    		index = indexRun * 8;

    		var texture = displayObject.texture;

    		var frame = texture.frame;
    		var tw = texture.baseTexture.width;
    		var th = texture.baseTexture.height;

    		this.uvs[index + 0] = frame.x / tw;
    		this.uvs[index +1] = frame.y / th;

    		this.uvs[index +2] = (frame.x + frame.width) / tw;
    		this.uvs[index +3] = frame.y / th;

    		this.uvs[index +4] = (frame.x + frame.width) / tw;
    		this.uvs[index +5] = (frame.y + frame.height) / th;

    		this.uvs[index +6] = frame.x / tw;
    		this.uvs[index +7] = (frame.y + frame.height) / th;

    		displayObject.updateFrame = false;

    		colorIndex = indexRun * 4;
    		this.colors[colorIndex] = this.colors[colorIndex + 1] = this.colors[colorIndex + 2] = this.colors[colorIndex + 3] = displayObject.worldAlpha;

    		displayObject = displayObject.__next;

    		indexRun ++;
    	}

    	this.dirtyUVS = true;
    	this.dirtyColors = true;
    }

    /**
     * Updates all the relevant geometry and uploads the data to the GPU
     * @method update
     */
    PIXI.WebGLBatch.prototype.update = function()
    {
    	var gl = this.gl;
    	var worldTransform, width, height, aX, aY, w0, w1, h0, h1, index, index2, index3

    	var a, b, c, d, tx, ty;

    	var indexRun = 0;

    	var displayObject = this.head;

    	while(displayObject)
    	{
    		if(displayObject.worldVisible)
    		{
    			width = displayObject.texture.frame.width;
    			height = displayObject.texture.frame.height;

    			// TODO trim??
    			aX = displayObject.anchor.x;// - displayObject.texture.trim.x
    			aY = displayObject.anchor.y; //- displayObject.texture.trim.y
    			w0 = width * (1-aX);
    			w1 = width * -aX;

    			h0 = height * (1-aY);
    			h1 = height * -aY;

    			index = indexRun * 8;

    			worldTransform = displayObject.worldTransform;

    			a = worldTransform[0];
    			b = worldTransform[3];
    			c = worldTransform[1];
    			d = worldTransform[4];
    			tx = worldTransform[2];
    			ty = worldTransform[5];

    			this.verticies[index + 0 ] = a * w1 + c * h1 + tx;
    			this.verticies[index + 1 ] = d * h1 + b * w1 + ty;

    			this.verticies[index + 2 ] = a * w0 + c * h1 + tx;
    			this.verticies[index + 3 ] = d * h1 + b * w0 + ty;

    			this.verticies[index + 4 ] = a * w0 + c * h0 + tx;
    			this.verticies[index + 5 ] = d * h0 + b * w0 + ty;

    			this.verticies[index + 6] =  a * w1 + c * h0 + tx;
    			this.verticies[index + 7] =  d * h0 + b * w1 + ty;

    			if(displayObject.updateFrame || displayObject.texture.updateFrame)
    			{
    				this.dirtyUVS = true;

    				var texture = displayObject.texture;

    				var frame = texture.frame;
    				var tw = texture.baseTexture.width;
    				var th = texture.baseTexture.height;

    				this.uvs[index + 0] = frame.x / tw;
    				this.uvs[index +1] = frame.y / th;

    				this.uvs[index +2] = (frame.x + frame.width) / tw;
    				this.uvs[index +3] = frame.y / th;

    				this.uvs[index +4] = (frame.x + frame.width) / tw;
    				this.uvs[index +5] = (frame.y + frame.height) / th;

    				this.uvs[index +6] = frame.x / tw;
    				this.uvs[index +7] = (frame.y + frame.height) / th;

    				displayObject.updateFrame = false;
    			}

    			// TODO this probably could do with some optimisation....
    			if(displayObject.cacheAlpha != displayObject.worldAlpha)
    			{
    				displayObject.cacheAlpha = displayObject.worldAlpha;

    				var colorIndex = indexRun * 4;
    				this.colors[colorIndex] = this.colors[colorIndex + 1] = this.colors[colorIndex + 2] = this.colors[colorIndex + 3] = displayObject.worldAlpha;
    				this.dirtyColors = true;
    			}
    		}
    		else
    		{
    			index = indexRun * 8;

    			this.verticies[index + 0 ] = 0;
    			this.verticies[index + 1 ] = 0;

    			this.verticies[index + 2 ] = 0;
    			this.verticies[index + 3 ] = 0;

    			this.verticies[index + 4 ] = 0;
    			this.verticies[index + 5 ] = 0;

    			this.verticies[index + 6] = 0;
    			this.verticies[index + 7] = 0;
    		}

    		indexRun++;
    		displayObject = displayObject.__next;
       }
    }

    /**
     * Draws the batch to the frame buffer
     * @method render
     */
    PIXI.WebGLBatch.prototype.render = function(start, end)
    {
    //	console.log(start + " :: " + end + " : " + this.size);
    	start = start || 0;
    	//end = end || this.size;
    	if(end == undefined)end = this.size;

    	if(this.dirty)
    	{
    		this.refresh();
    		this.dirty = false;
    	}

    	if (this.size == 0)return;

    	this.update();
    	var gl = this.gl;

    	//TODO optimize this!
    	gl.blendFunc(gl.ONE, gl.ONE_MINUS_SRC_ALPHA);

    	var shaderProgram = PIXI.shaderProgram;
    	gl.useProgram(shaderProgram);

    	// update the verts..
    	gl.bindBuffer(gl.ARRAY_BUFFER, this.vertexBuffer);
    	// ok..
    	gl.bufferSubData(gl.ARRAY_BUFFER, 0, this.verticies)
        gl.vertexAttribPointer(shaderProgram.vertexPositionAttribute, 2, gl.FLOAT, false, 0, 0);

    	// update the uvs
       	gl.bindBuffer(gl.ARRAY_BUFFER, this.uvBuffer);

        if(this.dirtyUVS)
        {
        	this.dirtyUVS = false;
        	gl.bufferSubData(gl.ARRAY_BUFFER,  0, this.uvs);
        }

        gl.vertexAttribPointer(shaderProgram.textureCoordAttribute, 2, gl.FLOAT, false, 0, 0);

        gl.activeTexture(gl.TEXTURE0);
        gl.bindTexture(gl.TEXTURE_2D, this.texture._glTexture);

    	// update color!
    	gl.bindBuffer(gl.ARRAY_BUFFER, this.colorBuffer);

    	if(this.dirtyColors)
        {
        	this.dirtyColors = false;
        	gl.bufferSubData(gl.ARRAY_BUFFER, 0, this.colors);
    	}

        gl.vertexAttribPointer(shaderProgram.colorAttribute, 1, gl.FLOAT, false, 0, 0);

    	// dont need to upload!
        gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, this.indexBuffer);

    	//var startIndex = 0//1;
    	var len = end - start;
    	// console.log(this.size)
        // DRAW THAT this!
        gl.drawElements(gl.TRIANGLES, len * 6, gl.UNSIGNED_SHORT, start * 2 * 6 );
    }