joshua goldberg

i've been trying to figure out jit.expr's ways, and i'm still smacking 

is there a single object jit.expr method of duplicating the plane-to- 

sphere method in the jit.gl.render.sphere example patch, duplicated 

i've been trying to figure out jit.expr's ways, and i'm still smacking  
my head against the wall a bit.

is there a single object jit.expr method of duplicating the plane-to- 
sphere method in the jit.gl.render.sphere example patch, duplicated  
below?

plane-to-sphere-in-a-single-jit-expr

the JavaScript from the audiovis_blob example, copied below, should 

do the trick. The basic expr is in there if you need it.

On Nov 16, 2007, at 11:30 AM, joshua goldberg wrote:

> i've been trying to figure out jit.expr's ways, and i'm still 

> smacking my head against the wall a bit.

> is there a single object jit.expr method of duplicating the plane- 

> to-sphere method in the jit.gl.render.sphere example patch, 

// small wrapper for a jit.expr which converts a 1d matrix representing

// a height field into a 3 plane matrix giving the coordinate of the 

var myexpr = new JitterObject("jit.expr");

myexpr.expr = ["in[0] * cos((norm[1]-0.5)*PI) * cos((norm[0]-0.5) 

    "in[0] * cos((norm[1]-0.5)*PI) * sin((norm[0]-0.5)*TWOPI)",

    "in[0] * sin((norm[1]-0.5)*PI)"];

    inputmatrix.op("+", "val", rest_size);

    myexpr.matrixcalc(inputmatrix, outputmatrix);

    outlet(0,"jit_matrix",outputmatrix.name);    

the JavaScript from the audiovis_blob example, copied below, should  
do the trick. The basic expr is in there if you need it.

> i've been trying to figure out jit.expr's ways, and i'm still  
> smacking my head against the wall a bit.
>
> is there a single object jit.expr method of duplicating the plane- 
> to-sphere method in the jit.gl.render.sphere example patch,  
> duplicated below?

// viz_poltocar
//
// small wrapper for a jit.expr which converts a 1d matrix representing
// a height field into a 3 plane matrix giving the coordinate of the  
field
// wrapped around a sphere.
//
// author: rej@2uptech.com

post ("---plane_to_spheren");
autowatch = 1;

var inputmatrix = new JitterMatrix();
var outputmatrix = new JitterMatrix();
var rest_size = 1.;

var myexpr = new JitterObject("jit.expr");
myexpr.planecount = 3;
myexpr.type = "float32";
myexpr.adapt = 1;
myexpr.interp = 0;

myexpr.expr = ["in[0] * cos((norm[1]-0.5)*PI) * cos((norm[0]-0.5) 
*TWOPI)",
	"in[0] * cos((norm[1]-0.5)*PI) * sin((norm[0]-0.5)*TWOPI)",
	"in[0] * sin((norm[1]-0.5)*PI)"];

function jit_matrix(inname)
{
	inputmatrix.setinfo(inname);
	inputmatrix.frommatrix(inname);

	outputmatrix.setinfo(inname);
	outputmatrix.planecount = 3;

	myexpr.matrixcalc(inputmatrix, outputmatrix);

	outlet(0,"jit_matrix",outputmatrix.name);	
}


Here is the formula as shader vertex code.

Thanks Wes and Marius (but it isn't quite round!)

// shader es.planesphere.vp.glsl code (())_n

    t_point.x = cos(pp.x-1.57074)*acc;

    t_point.z = sin(pp.x-1.57074)*acc;

    s_point = mix(s_point,t_point,shape);

    vec4 W = vec4( surface(gl_Vertex.xy), 1.);

    vec3 neighbour1 = surface(vec2(gl_Vertex.x + delta, gl_Vertex.y));

    vec3 neighbour2 = surface(vec2(gl_Vertex.x, gl_Vertex.y + delta));

    vec3 tangent = normalize(neighbour1 - W.xyz);

    vec3 bitangent = normalize(neighbour2 - W.xyz);

    N = normalize( cross(tangent, bitangent) );

    N = mat3(    gl_ModelViewMatrixInverseTranspose[0].xyz,

                gl_ModelViewMatrixInverseTranspose[1].xyz,

                gl_ModelViewMatrixInverseTranspose[2].xyz)*N;

    texdim0 = vec2 (abs(gl_TextureMatrix[0][0][0]),abs(gl_TextureMatrix 

texcoord0 = vec2(gl_TextureMatrix[0] * gl_MultiTexCoord0);

    gl_Position = gl_ModelViewProjectionMatrix*W;

On Nov 16, 2007, at 2:59 PM, Randy Jones wrote:

> the JavaScript from the audiovis_blob example, copied below, should 

> do the trick. The basic expr is in there if you need it.

> On Nov 16, 2007, at 11:30 AM, joshua goldberg wrote:

>> i've been trying to figure out jit.expr's ways, and i'm still 

>> smacking my head against the wall a bit.

>> is there a single object jit.expr method of duplicating the plane- 

>> to-sphere method in the jit.gl.render.sphere example patch, 

> // small wrapper for a jit.expr which converts a 1d matrix 

> // a height field into a 3 plane matrix giving the coordinate of 

> var myexpr = new JitterObject("jit.expr");

> myexpr.expr = ["in[0] * cos((norm[1]-0.5)*PI) * cos((norm[0]-0.5) 

>     "in[0] * cos((norm[1]-0.5)*PI) * sin((norm[0]-0.5)*TWOPI)",

>     "in[0] * sin((norm[1]-0.5)*PI)"];

Here is the formula as shader vertex code.
Thanks Wes and Marius (but it isn't quite round!)
Get the patch, etc. here:

varying vec4 V;
varying vec3 N;
varying vec3 P;
varying vec2 texcoord0;
varying vec2 texdim0;

uniform float shape;
uniform float delta;

vec3 surface(vec2 point)
{	
	vec2 p; // plane
	p.x = (point.x - 0.5) * 2.;
	p.y = (point.y - 0.5) * -2.;
	vec3 s_point;
	s_point.x = p.x * 1.33;
	s_point.y = p.y;
	s_point.z = 0.;

	vec2 pp; // sphere
	pp.x = (point.x-1.) * -2. * PI;
	pp.y = point.y * PI;
	float acc = sin(pp.y);
	vec3 t_point;
	t_point.x = cos(pp.x-1.57074)*acc;
	t_point.z = sin(pp.x-1.57074)*acc;
	t_point.y = cos(pp.y);

	s_point = mix(s_point,t_point,shape);
	return s_point;
}

void main (void)
{
	vec4 W = vec4( surface(gl_Vertex.xy), 1.);

	vec3 neighbour1 = surface(vec2(gl_Vertex.x + delta, gl_Vertex.y));
	vec3 neighbour2 = surface(vec2(gl_Vertex.x, gl_Vertex.y + delta));

	vec3 tangent = normalize(neighbour1 - W.xyz);
	vec3 bitangent = normalize(neighbour2 - W.xyz);

	//get the normals into eye space
	N = normalize( cross(tangent, bitangent) );
	N = mat3(	gl_ModelViewMatrixInverseTranspose[0].xyz,
				gl_ModelViewMatrixInverseTranspose[1].xyz,
				gl_ModelViewMatrixInverseTranspose[2].xyz)*N;

	texdim0 = vec2 (abs(gl_TextureMatrix[0][0][0]),abs(gl_TextureMatrix 
[0][1][1]));
     texcoord0 = vec2(gl_TextureMatrix[0] * gl_MultiTexCoord0);

	gl_Position = gl_ModelViewProjectionMatrix*W;
}

>
> Hi Joshua,
>
> the JavaScript from the audiovis_blob example, copied below, should  
> do the trick. The basic expr is in there if you need it.
>
> best,
> Randy
>
>
> On Nov 16, 2007, at 11:30 AM, joshua goldberg wrote:
>
>> i've been trying to figure out jit.expr's ways, and i'm still  
>> smacking my head against the wall a bit.
>>
>> is there a single object jit.expr method of duplicating the plane- 
>> to-sphere method in the jit.gl.render.sphere example patch,  
>> duplicated below?
>
>
>
>
> // viz_poltocar
> //
> // small wrapper for a jit.expr which converts a 1d matrix  
> representing
> // a height field into a 3 plane matrix giving the coordinate of  
> the field
> // wrapped around a sphere.
> //
> // author: rej@2uptech.com
>
> post ("---plane_to_spheren");
> autowatch = 1;
>
> var inputmatrix = new JitterMatrix();
> var outputmatrix = new JitterMatrix();
> var rest_size = 1.;
>
> var myexpr = new JitterObject("jit.expr");
> myexpr.planecount = 3;
> myexpr.type = "float32";
> myexpr.adapt = 1;
> myexpr.interp = 0;
>
> myexpr.expr = ["in[0] * cos((norm[1]-0.5)*PI) * cos((norm[0]-0.5) 
> *TWOPI)",
> 	"in[0] * cos((norm[1]-0.5)*PI) * sin((norm[0]-0.5)*TWOPI)",
> 	"in[0] * sin((norm[1]-0.5)*PI)"];
>
> function jit_matrix(inname)
> {
> 	inputmatrix.setinfo(inname);
> 	inputmatrix.frommatrix(inname);
>
> 	outputmatrix.setinfo(inname);
> 	outputmatrix.planecount = 3;
>
> 	inputmatrix.op("+", "val", rest_size);
>
> 	myexpr.matrixcalc(inputmatrix, outputmatrix);
>
> 	outlet(0,"jit_matrix",outputmatrix.name);	
> }
>
>
>


> Here is the formula as shader vertex code.

> Thanks Wes and Marius (but it isn't quite round!)

This is really weird. To me it looks like cos and sin are giving 

http://www.parasitaere-kapazitaeten.net/max_msp/sphereshape

I am still thinking about a better wrapping formula.

(())_n wrote:
> HI Joshua, Randy,
>
> Here is the formula as shader vertex code.
> Thanks Wes and Marius (but it isn't quite round!)

This is really weird. To me it looks like cos and sin are giving 
unprecise output. maybe rounding errors?
http://www.parasitaere-kapazitaeten.net/max_msp/sphereshape
I am still thinking about a better wrapping formula.
marius.


plane-to-sphere in a single jit.expr?