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I just spent a lot of time getting all the array loops to work without error,
and now POV complains
Parse Error: Expected 'RValue to declare', End of File found instead
or if I comment out the #end where it chokes, then I get "end of file reached,
but #end expected.
As far as I can see, all my #locals have a ; and all my #fors have an #end
Hoping someone can help me spot where in the chain it's all going wrong.
I'll keep hunting backward
(This is fourth time I'm posting this - seems to be a problem getting it to
"take" via the web interface in p.b.scene files)
===============================================================
#version 3.7;
global_settings { assumed_gamma 1.0 }
//------------------------------------------
// SDL for making a Bezier spline - given 4 data points, compute control points
p1 and p2
// Bill Walker - 2016
// Adapted code to POV-Ray from :
// https://www.particleincell.com/2012/bezier-splines/
// https://www.particleincell.com/wp-content/uploads/2012/06/circles.svg
// replace var with #declare or #local, function with #macro, edit #for() #end
syntax, array[] syntax
//------------------------------------------
#include "colors.inc"
#include "debug.inc"
Set_Debug (true)
#include "math.inc"
light_source { <0, 50, -50> color rgb <1, 1, 1>}
#declare Camera_Front =
camera {
location <0, 90, -1>
//right x*image_width/image_height
look_at <0, 0, 0>}
camera {Camera_Front}
// bezier-spline.js
// computes cubic bezier coefficients to generate a smooth
// line through specified points. couples with SVG graphics
// for interactive processing.
// For more info see:
// http://www.particleincell.com/2012/bezier-splines/
// Lubos Brieda, Particle In Cell Consulting LLC, 2012
// you may freely use this algorithm in your codes however where feasible
// please include a link/reference to the source article
//#declare svg=document.documentElement //svg object
#declare S = array[4]; //splines
#declare V = array[4]; //vertices
//#declare C //current object
//#declare x0,y0 //svg offset
#declare K = array[4];
#macro init()
//##################################################################################
//saves elements as global variables
//create splines
//#declare S[0] = createPath("blue");
//#declare S[1] = createPath("red");
//#declare S[2] = createPath("green");
//#declare S[3] = createPath("brown");
//create control points
#declare V[0] = <60,60,0>;
createKnot(V[0])
#declare V[1] = <220,300,0>;
createKnot(V[1])
#declare V[2] = <420,300,0>;
createKnot(V[2])
#declare V[3] = <700,240,0>;
createKnot(V[3])
updateSplines()
#end // end macro init
//##################################################################################
#macro createPath(Color, Width)
//##################################################################################
//creates and adds an SVG path without defining the nodes
//width = (typeof width == 'undefined' ? "8" : width);
//#declare P=document.createElementNS("http://www.w3.org/2000/svg","path")
//P.setAttributeNS(null,"fill","none")
//P.setAttributeNS(null,"stroke",color)
//P.setAttributeNS(null,"stroke-width",width)
//svg.appendChild(P)
//return P
#end
//##################################################################################
#macro createKnot(V)
//##################################################################################
//creates and adds an SVG circle to represent knots
sphere { V 22 pigment {Yellow}}
//#declare C=document.createElementNS("http://www.w3.org/2000/svg","circle")
//C.setAttributeNS(null,"r",22)
//C.setAttributeNS(null,"cx",x)
//C.setAttributeNS(null,"cy",y)
//C.setAttributeNS(null,"fill","gold")
//C.setAttributeNS(null,"stroke","black")
//C.setAttributeNS(null,"stroke-width","6")
//C.setAttributeNS(null,"onmousedown","startMove(evt)")
//svg.appendChild(C)
//return C
#end // end macro createKnot
//##################################################################################
// Maybe set up java mouse movement as clock-linked animation
//from http://www.w3.org/Graphics/SVG/IG/resources/svgprimer.html
/* #macro startMove(evt)
SVG positions are relative to the element but mouse positions are relative to
the window, get offset
x0 = getOffset(svg).left;
y0 = getOffset(svg).top;
C=evt.target
svg.setAttribute("onmousemove","move(evt)")
svg.setAttribute("onmouseup","drop()")
#end // end macro startMove
//called on mouse move, updates dragged circle and recomputes splines
#macro move(evt)
x = evt.clientX-x0;
y = evt.clientY-y0;
move the current handle
C.setAttributeNS(null,"cx",x)
C.setAttributeNS(null,"cy",y)
updateSplines();
#end // end macro move
//called on mouse up event
#macro drop()
svg = document.getElementsByTagName('svg')[0];
svg.setAttributeNS(null, "onmousemove",null)
#end // end macro drop
*/
#macro updateSplines()
//##################################################################################
//computes spline control points
//grab (x,y) coordinates of the control points
#local X = array[4];
#local Y = array[4];
#for (i, 0, 3) //for (i=0;i<4;i++)
//use parseInt to convert string to int
#local X[i] = V[i]; //parseInt(V[i].getAttributeNS(null,"cx"))
#local Y[i] = V[i]; //parseInt(V[i].getAttributeNS(null,"cy"))
#end
//computes control points p1 and p2 for x and y direction
#local px = computeControlPoints(X);
#local py = computeControlPoints(Y);
//updates path settings, the browser will draw the new spline
#for (i, 0, 2) //for (i=0;i<3;i++)
//S[i].setAttributeNS(null,"d",
path(x[i],y[i],px.p1[i],py.p1[i],px.p2[i],py.p2[i],x[i+1],y[i+1]));
//#debug concat( "(Draw SVG path subroutine) i = ", str(i, 3, 1), "\n")
#end
#end // end macro updateSplines ^^^^ call path macro
//##################################################################################
#macro path(x1,y1,px1,py1,px2,py2,x2,y2)
//##################################################################################
//creates formated path string for SVG cubic path element
//return "M "+x1+" "+y1+" C "+px1+" "+py1+" "+px2+" "+py2+" "+x2+" "+y2;
#end // end macro paths
//##################################################################################
#macro computeControlPoints(K)
//##################################################################################
//computes control points given knots K, this is the brain of the operation
#local p1 = array[4];
#local p2 = array[4];
#local n = dimension_size (K, 1) - 1; //K.length-1;
//rhs vector
#local a = array[n];
#local b = array[n];
#local c = array[n];
#local r = array[n];
//left most segment
#local a[0] = 0;
#local b[0] = 2;
#local c[0] = 1;
#local r[0] = K[0] + 2 * K[1];
//internal segments
#for (i, 0, n-2) //(i = 1; i < n - 1; i++)
#local a[i] = 1;
#local b[i] = 4;
#local c[i] = 1;
#local r[i] = 4 * K[i] + 2 * K[i+1];
#end
//right segment
#local a[n-1] = 2;
#local b[n-1] = 7;
#local c[n-1] = 0;
#local r[n-1] = 8 * K[n-1] + K[n];
//solves Ax=b with the Thomas algorithm (from Wikipedia)
#for (i, 1, n-1) //#for (i = 1; i < n; i++)
#local m = a[i]/b[i-1];
#local b[i] = b[i] - m * c[i - 1];
#local r[i] = r[i] - m*r[i-1];
#end
#local p1[n-1] = r[n-1]/b[n-1]; //#local p1[n-1] = r[n-1]/b[n-1];
// {Be sure to include debug.inc file!}
//#debug concat( "Defining p1. n-1 = ", str((n-1), 3, 1), "\n")
#for (i, n-2, 0, -1) //#for (i = n - 2; i >= 0; --i)
#local p1[i] = (r[i] - c[i] * p1[i+1]) / b[i];
//#debug concat( "Defining p1. i = ", str(i, 3, 1), " Defining p1. i+1 =
", str((i+1), 3, 1),"\n")
#end
//we have p1, now compute p2
#for (i, 0, n-2) //#for (i=0;i<n-1;i++)
//#debug concat( "Defining p2 i = ", str(i, 3, 1), " i+1 = ", str((i+1),
3, 1),"\n")
#local p2[i] = 2 * K[i+1] - p1[i+1];
#end
#local p2[n-1] = 0.5 * (K[n] + p1[n-1]);
//return {p1:p1, p2:p2};
#end // end macro computeControlPoints
//##################################################################################
//code from
http://stackoverflow.com/questions/442404/dynamically-retrieve-html-element-x-y-position-with-javascript
//#macro getOffset( el )
// #declare _x = 0;
// #declare _y = 0;
// while( el && !isNaN( el.offsetLeft ) && !isNaN( el.offsetTop ) ) {
// _x += el.offsetLeft - el.scrollLeft;
// _y += el.offsetTop - el.scrollTop;
// el = el.offsetParent;
//
// return { top: _y, left: _x };
//call macros
init ()
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de> wrote: