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I'm having problems sorting out my glpushmatrix and glpopmatrix dance in the posted patch and code below. I'm new to Javascript, but not new to Max. Essentially list "segments" is a list of x-axis values that are combined with a list "speed" of y axis values that combine to draw a bunch of polygons forming a shape. "Segments" will also be combined with other parameter lists to form other shapes which I would like to transform, different colour, etc.

How can I push and pop correctly to avoid the old over/under flow/flow errors?

Edit: Max patch copy-compressed and pasted Javascript pasted below.

// to parse the incoming data from and 
// create a set of gl.sketch commands that draw the paramter line
// as a set of polygons

inlets = 1
outlets = 1

var mySketch = new JitterObject("jit.gl.sketch", "TEST");
var xArray = new Array();

function reset()
{
    mySketch.reset(); // reset things as needed especially for testing
    xArray = [];
    yArray = [];
}

function segments()
{
    xArray = arrayfromargs(arguments); // get the arguments for "segments" as an array
    mySketch.reset();
}

function speed()
{    
    yArray = arrayfromargs(arguments);
    
    // if I push and pop this I get "ob3d_draw_end popmatrix: GL Error: Stack overflow"
    // if I don't I get no error unless calling a second,
    // similar function like activityLevel below
    
    mySketch.glpushmatrix(); 
    mySketch.glscale([2, 1, 1]);
    mySketch.gltranslate([0, 0, -10]);
    mySketch.glcolor([1., 1., 1.]);

    for (var i = 0; i < xArray.length - 1; i++)
    {
        var j = i*2;
        var x1 = ((xArray[i] - 300) * 0.01);
        var x2 = ((xArray[i+1] - 300) * 0.01);
        var y1 = ((yArray[j] - 0.5) * 2.);
        var y2 = ((yArray[j+1] - 0.5) * 2.);

        mySketch.glbegin("polygon");
        mySketch.glvertex(x1, y1);
        mySketch.glvertex(x1, -5);
        mySketch.glvertex(x2, -5);
        mySketch.glvertex(x2, y2);
        mySketch.glend;
        //post(x1, y1, ", ", x1, " -5, ", x2, " -5, ",  x2, y2, "\n");
    }
    mySketch.glpopmatrix();
}

/*
function activityLevel()
{    
    yArray = arrayfromargs(arguments);
    
    //No problems if I don't tranform at all
    
    //mySketch.glpushmatrix();
    //mySketch.glscale([2, 1, 1]);
    //mySketch.gltranslate([-1, 0, -5]);
    //mySketch.glcolor([.5, .75, 1.]);
    
    for (var i = 0; i < xArray.length - 1; i++)
    {
        var j = i*2;
        var x1 = ((xArray[i] - 300) * 0.01);
        var x2 = ((xArray[i+1] - 300) * 0.01);
        var y1 = ((yArray[j] - 0.5) * 2.);
        var y2 = ((yArray[j+1] - 0.5) * 2.)
        
        mySketch.glbegin("polygon");
        mySketch.glvertex(x1, y1);
        mySketch.glvertex(x1, -5);
        mySketch.glvertex(x2, -5);
        mySketch.glvertex(x2, y2);
        mySketch.glend;
        
        //post(x1, y1, ", ", x1, " -5, ", x2, " -5, ",  x2, y2, "\n");
    }
    //mySketch.glpopmatrix();
}
*/

PPF.js

// to parse the incoming data from and 
// create a set of gl.sketch commands that draw the paramter line
// as a set of polygons

inlets = 1
outlets = 1

var mySketch = new JitterObject("jit.gl.sketch", "TEST");
var xArray = new Array();

function reset()
{
    mySketch.reset(); // reset things as needed especially for testing
    xArray = [];
    yArray = [];
}

function segments()
{
    xArray = arrayfromargs(arguments); // get the arguments for "segments" as an array
    mySketch.reset();
}

function speed()
{	
	yArray = arrayfromargs(arguments);
	
	// if I push and pop this I get "ob3d_draw_end popmatrix: GL Error: Stack overflow"
	// if I don't I get no error unless calling a second,
	// similar function like activityLevel below
	
	mySketch.glpushmatrix(); 
	mySketch.glscale([2, 1, 1]);
	mySketch.gltranslate([0, 0, -10]);
	mySketch.glcolor([1., 1., 1.]);

	for (var i = 0; i < xArray.length - 1; i++)
	{
		var j = i*2;
		var x1 = ((xArray[i] - 300) * 0.01);
		var x2 = ((xArray[i+1] - 300) * 0.01);
		var y1 = ((yArray[j] - 0.5) * 2.);
		var y2 = ((yArray[j+1] - 0.5) * 2.);

		mySketch.glbegin("polygon");
		mySketch.glvertex(x1, y1);
		mySketch.glvertex(x1, -5);
		mySketch.glvertex(x2, -5);
		mySketch.glvertex(x2, y2);
		mySketch.glend;
		//post(x1, y1, ", ", x1, " -5, ", x2, " -5, ",  x2, y2, "\n");
	}
	mySketch.glpopmatrix();
}

/*
function activityLevel()
{	
	yArray = arrayfromargs(arguments);
	
	//No problems if I don't tranform at all
	
	//mySketch.glpushmatrix();
	//mySketch.glscale([2, 1, 1]);
	//mySketch.gltranslate([-1, 0, -5]);
	//mySketch.glcolor([.5, .75, 1.]);
	
	for (var i = 0; i < xArray.length - 1; i++)
	{
		var j = i*2;
		var x1 = ((xArray[i] - 300) * 0.01);
		var x2 = ((xArray[i+1] - 300) * 0.01);
		var y1 = ((yArray[j] - 0.5) * 2.);
		var y2 = ((yArray[j+1] - 0.5) * 2.)
		
		mySketch.glbegin("polygon");
		mySketch.glvertex(x1, y1);
		mySketch.glvertex(x1, -5);
		mySketch.glvertex(x2, -5);
		mySketch.glvertex(x2, y2);
		mySketch.glend;
		
		//post(x1, y1, ", ", x1, " -5, ", x2, " -5, ",  x2, y2, "\n");
	}
	//mySketch.glpopmatrix();
}
*/

I'm having problems sorting out my glpushmatrix and glpopmatrix dance in the posted patch and code below. I'm new to Javascript, but not new

the-pushpop-overunder-flowflow

Well, all the other examples I can find appear to do all the rendering/draw in the javascript as well, which likely keeps a correct order of events/command list items. My project is mixed between object patching and this script, which is really just to parse some data into some shapes. That is, only needs to run at initialization. So I will try changing the script to just parse and format a set of messages to an external (to the script) jit.gl.sketch object like the js_jitterspline example and see if that helps sort things out.

Well, all the other examples I can find appear to do all the rendering/draw in the javascript as well, which likely keeps a correct order of events/command list items.  My project is mixed between object patching and this script, which is really just to parse some data into some shapes. That is, only needs to run at initialization. So I will try changing the script to just parse and format a set of messages to an external (to the script) jit.gl.sketch object like the js_jitterspline example and see if that helps sort things out.

yeah, i'm not really sure why this is spitting out those errors. i don't see anything wrong with your script.

any chance i can convince you to use jit.gl.mesh @draw_mode polygon instead of jit.gl.sketch for this type of thing?

There is a very strong chance. I'll look into it, give it a whirl. Thanks for having a look.

The Push/Pop, Over/Under, Flow/Flow