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curvex.js
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curvex.js
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function isFlt( val, def )
{
val = Number.parseFloat(val);
if ( !(Number.isFinite(val)) )
return isFlt( def, 0 );
return val;
}
function isInt( val, def )
{
val = Number.parseInt(val);
if ( !(Number.isInteger(val)) )
return isInt( def, 0 );
return val;
}
function both_sizes(cbox)
{
var form = cbox.form;
form.nHeight.disabled = cbox.checked;
}
function link_sizes(nWidth)
{
var form = nWidth.form, nHeight = form.nHeight;
if ( nHeight.disabled )
nHeight.value = nWidth.value;
}
function createPositionsBuffer( gl, positions ) {
// Create a buffer for the square's positions.
const buff = gl.createBuffer();
// Select the positionBuffer as the one to apply buffer
// operations to from here out.
gl.bindBuffer( gl.ARRAY_BUFFER, buff );
// Now pass the list of positions into WebGL to build the
// shape. We do this by creating a Float32Array from the
// JavaScript array, then use it to fill the current buffer.
gl.bufferData(
gl.ARRAY_BUFFER,
new Float32Array( positions ),
gl.STATIC_DRAW
);
return buff;
}
function newPointXY( x, y )
{
return { x : x, y : y };
}
function buildSolidTriangle( points, a, b, c )
{
points.push( a.x, a.y, b.x, b.y, c.x, c.y );
return points;
}
function cxDraw( box, gl, app, vxaPoints, sides, width, height )
{
var ret = { border: 0, area: 0, html: "" };
var points = [];
gl.viewport( 0, 0, gl.canvas.width, gl.canvas.height );
gl.clearColor( 0.0, 0.0, 0.0, 1.0 );
gl.clear( gl.COLOR_BUFFER_BIT );
gl.useProgram( app );
gl.enableVertexAttribArray( vxaPoints );
var pxWidth = box.clientWidth, pxHeight = box.clientHeight, mine = 0;
var radius = width / 2
, half = sides / 2
, stop = sides / 4
, middle = stop / 2
, scaleX = 1 / pxWidth
, scaleY = 1 / pxHeight
, sizeX = 1 / 40
, sizeY = 1 / 40
, curve = 2
, div = 1 / stop
, frac = div / stop
, square1 = (width < height) ? width * width : height * height
, square2 = (width > height) ? width * width : height * height
, addmore = 1
, border_len = 0
, one = (Math.sqrt(square2 * 2)) * frac
, two = (Math.sqrt(square1 + (square2 * 2))) * frac;
stop -= 2;
console.log( "stop: " + stop + "; div: " + div + "; frac: " + frac );
for ( var i = 1, x = 0, y = 1; i < stop; ++i )
{
var X = (0.225 - x) * scaleX * width, Xp = (X + sizeX), Xm = (X - sizeX);
var Y = (1 - y) * scaleY * height, Yp = (Y + sizeY), Ym = (Y - sizeY);
console.log( "X = " + X + "; Y = " + Y );
points = buildSolidTriangle
(
points
, newPointXY( Xm, Ym )
, newPointXY( X, Y )
, newPointXY( Xp, Ym )
);
points = buildSolidTriangle
(
points
, newPointXY( -Xm, Ym )
, newPointXY( -X, Y )
, newPointXY( -Xp, Ym )
);
points = buildSolidTriangle
(
points
, newPointXY( Xm, -Ym )
, newPointXY( X, -Y )
, newPointXY( Xp, -Ym )
);
points = buildSolidTriangle
(
points
, newPointXY( -Xm, -Ym )
, newPointXY( -X, -Y )
, newPointXY( -Xp, -Ym )
);
x += frac + ((frac * curve) * (i == curve));
y -= frac + ((frac * (stop - curve)) * (i == curve));
curve += 2 * (i == curve);
mine += (one * (i != curve)) + (two * (i == curve));
}
stop += 2;
//border_len = ((mine * width) + (mine * height)) / (stop * (1+((1/3.75))));
border_len = ((sides * one) + (sides * two)) * 6.24;
console.log( "one = " + one );
console.log( "two = " + two );
ret.area = border_len / 2;
ret.border = border_len;
const vxPoints = createPositionsBuffer( gl, points );
gl.bindBuffer( gl.ARRAY_BUFFER, vxPoints );
// Tell the attribute how to get data out of positionBuffer (ARRAY_BUFFER)
var size = 2; // 2 components per iteration
var type = gl.FLOAT; // the data is 32bit floats
var normalize = false; // don't normalize the data
var stride = 0; // 0 = move forward size * sizeof(type) each iteration to get the next position
var offset = 0; // start at the beginning of the buffer
gl.vertexAttribPointer
(
vxaPoints
, size
, type
, normalize
, stride
, offset
);
var primitiveType = gl.TRIANGLES;
var offset = 0;
var count = points.length / 2;
gl.drawArrays( primitiveType, offset, count );
return ret;
}
function piDraw( box, gl, app, vxaPoints, sides, width, height )
{
var ret = { border: 0, area: 0, html: "" };
var points = [];
gl.viewport( 0, 0, gl.canvas.width, gl.canvas.height );
gl.clearColor( 0.0, 0.0, 0.0, 1.0 );
gl.clear( gl.COLOR_BUFFER_BIT );
gl.useProgram( app );
gl.enableVertexAttribArray( vxaPoints );
var pxWidth = box.clientWidth, pxHeight = box.clientHeight, mine = 0;
var radius = (width / 4) + (height / 4)
, half = sides / 2
, stop = sides / 4
, middle = stop / 2
, scaleX = 1 / pxWidth
, scaleY = 1 / pxHeight
, sizeX = 1 / 40
, sizeY = 1 / 40
, div = 1 / stop
, frac = div / stop;
stop -= 2;
console.log( "stop: " + stop + "; div: " + div + "; frac: " + frac );
for ( var i = 1, x = 0, y = 1; i < stop; ++i )
{
var xy = x + y;
var X = xy * scaleX * width, Xp = (X + sizeX), Xm = (X - sizeX);
var Y = xy * scaleY * height, Yp = (Y + sizeY), Ym = (Y - sizeY);
console.log( "X = " + X + "; Y = " + Y );
points = buildSolidTriangle
(
points
, newPointXY( Xm, Ym )
, newPointXY( X, Y )
, newPointXY( Xp, Ym )
);
points = buildSolidTriangle
(
points
, newPointXY( -Xm, Ym )
, newPointXY( -X, Y )
, newPointXY( -Xp, Ym )
);
points = buildSolidTriangle
(
points
, newPointXY( Xm, -Ym )
, newPointXY( X, -Y )
, newPointXY( Xp, -Ym )
);
points = buildSolidTriangle
(
points
, newPointXY( -Xm, -Ym )
, newPointXY( -X, -Y )
, newPointXY( -Xp, -Ym )
);
x += frac;
y -= frac;
}
stop += 2;
ret.area = Math.PI * radius;
ret.border = Math.PI * 2 * radius;
const vxPoints = createPositionsBuffer( gl, points );
gl.bindBuffer( gl.ARRAY_BUFFER, vxPoints );
// Tell the attribute how to get data out of positionBuffer (ARRAY_BUFFER)
var size = 2; // 2 components per iteration
var type = gl.FLOAT; // the data is 32bit floats
var normalize = false; // don't normalize the data
var stride = 0; // 0 = move forward size * sizeof(type) each iteration to get the next position
var offset = 0; // start at the beginning of the buffer
gl.vertexAttribPointer
(
vxaPoints
, size
, type
, normalize
, stride
, offset
);
var primitiveType = gl.TRIANGLES;
var offset = 0;
var count = points.length / 2;
gl.drawArrays( primitiveType, offset, count );
return ret;
}
function openWebGL( nBox )
{
var gl = nBox.getContext("webgl");
gl = gl ? gl : nBox.getContext("2d");
if ( !gl )
{
alert("Couldn't open WebGL!");
return null;
}
return gl;
}
function newShader(gl, type, code) {
const shader = gl.createShader( type );
// Send the source to the shader object
gl.shaderSource( shader, code );
// Compile the shader program
gl.compileShader( shader );
// See if it compiled successfully
if (!gl.getShaderParameter( shader, gl.COMPILE_STATUS) )
{
alert
(
'An error occurred compiling the shaders: '
+ gl.getShaderInfoLog( shader )
);
gl.deleteShader( shader );
return null;
}
return shader;
}
function newApp( gl, vsCode, fsCode )
{
// Initialize a shader program, so WebGL knows how to draw our data
const vs = newShader( gl, gl.VERTEX_SHADER, vsCode );
const fs = newShader( gl, gl.FRAGMENT_SHADER, fsCode );
const ctx = gl.createProgram();
gl.attachShader( ctx, vs );
gl.attachShader( ctx, fs );
gl.linkProgram( ctx );
if ( !gl.getProgramParameter( ctx, gl.LINK_STATUS ) ) {
alert(
'Unable to initialize the ctx program: '
+ gl.getProgramInfoLog( ctx )
);
return null;
}
return ctx;
}
var _cxGL = null, _piGL = null;
const _vsCode = `
// an attribute will receive data from a buffer
attribute vec4 aPoints;
// all shaders have a main function
void main() {
// gl_Position is a special variable a vertex shader
// is responsible for setting
gl_Position = aPoints;
}`;
const _fsCode = `
// fragment shaders don't have a default precision so we need
// to pick one. mediump is a good default. It means "medium precision"
precision mediump float;
void main()
{
// gl_FragColor is a special variable a fragment shader
// is responsible for setting
gl_FragColor = vec4(1, 0, 0.5, 1); // return reddish-purple
}`;
function main(form)
{
var nSides = form.nSides, nWidth = form.nWidth, nHeight = form.nHeight;
var sides = isInt( nSides.value, 100 );
var width = isFlt( nWidth.value, 1000 );
var height = isFlt( nHeight.value, 1000 );
for ( i = sides / 4; Math.floor(i) < i; ++sides, i = sides / 4 );
width += (width <= 0);
height += (height <= 0);
nSides.value = sides;
nWidth.value = width;
nHeight.value = height;
var nhRadius = form.nhRadius, nvRadius = form.nvRadius;
var hradius = width / 2, vradius = height / 2;
nhRadius.value = hradius;
nvRadius.value = vradius;
var cxBox = form.cxBox.lastElementChild.firstElementChild;
var piBox = form.piBox.lastElementChild.firstElementChild;
var cxGL = openWebGL(cxBox, _cxGL), cxApp = newApp( cxGL, _vsCode, _fsCode );
var piGL = openWebGL(piBox, _piGL), piApp = newApp( piGL, _vsCode, _fsCode );
const cx_vxaPoints = cxGL.getAttribLocation ( cxApp, 'aPoints' );
const pi_vxaPoints = piGL.getAttribLocation ( piApp, 'aPoints' );
var cxOut = cxDraw( cxBox, cxGL, cxApp, cx_vxaPoints, sides, width, height );
var piOut = piDraw( piBox, piGL, piApp, pi_vxaPoints, sides, width, height );
_cxGL = cxGL;
_piGL = piGL;
form.cxWidth.value = cxBox.clientWidth;
form.piWidth.value = piBox.clientWidth;
form.cxHeight.value = cxBox.clientHeight;
form.piHeight.value = piBox.clientHeight;
form.cxArea.value = cxOut.area;
form.piArea.value = piOut.area;
form.cxBorder.value = cxOut.border;
form.piBorder.value = piOut.border;
form.cxAreaDividedByBorder.value = cxOut.border / cxOut.area;
form.piAreaDividedByBorder.value = piOut.border / piOut.area;
form.cxWidthPI.value = cxOut.border / width;
form.piWidthPI.value = piOut.border / width;
form.cxHeightPI.value = cxOut.border / height;
form.piHeightPI.value = piOut.border / height;
form.cxPI.value = cxOut.border / ((height / 2) + (width / 2));
form.piPI.value = piOut.border / ((height / 2) + (width / 2));
form.cxBox.lastElementChild.lastElementChild.innerHTML = cxOut.html;
form.piBox.lastElementChild.lastElementChild.innerHTML = piOut.html;
}