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| "use strict";
var MonotoneMesh = (function(){
function MonotonePolygon(c, v, ul, ur) {
this.color = c;
this.left = [[ul, v]];
this.right = [[ur, v]];
};
MonotonePolygon.prototype.close_off = function(v) {
this.left.push([ this.left[this.left.length-1][0], v ]);
this.right.push([ this.right[this.right.length-1][0], v ]);
};
MonotonePolygon.prototype.merge_run = function(v, u_l, u_r) {
var l = this.left[this.left.length-1][0]
, r = this.right[this.right.length-1][0];
if(l !== u_l) {
this.left.push([ l, v ]);
this.left.push([ u_l, v ]);
}
if(r !== u_r) {
this.right.push([ r, v ]);
this.right.push([ u_r, v ]);
}
};
return function(volume, dims) {
function f(i,j,k) {
return volume[i + dims[0] * (j + dims[1] * k)];
}
//Sweep over 3-axes
var vertices = [], faces = [];
for(var d=0; d<3; ++d) {
var i, j, k
, u = (d+1)%3 //u and v are orthogonal directions to d
, v = (d+2)%3
, x = new Int32Array(3)
, q = new Int32Array(3)
, runs = new Int32Array(2 * (dims[u]+1))
, frontier = new Int32Array(dims[u]) //Frontier is list of pointers to polygons
, next_frontier = new Int32Array(dims[u])
, left_index = new Int32Array(2 * dims[v])
, right_index = new Int32Array(2 * dims[v])
, stack = new Int32Array(24 * dims[v])
, delta = [[0,0], [0,0]];
//q points along d-direction
q[d] = 1;
//Initialize sentinel
for(x[d]=-1; x[d]<dims[d]; ) {
// --- Perform monotone polygon subdivision ---
var n = 0
, polygons = []
, nf = 0;
for(x[v]=0; x[v]<dims[v]; ++x[v]) {
//Make one pass over the u-scan line of the volume to run-length encode polygon
var nr = 0, p = 0, c = 0;
for(x[u]=0; x[u]<dims[u]; ++x[u], p = c) {
//Compute the type for this face
var a = (0 <= x[d] ? f(x[0], x[1], x[2]) : 0)
, b = (x[d] < dims[d]-1 ? f(x[0]+q[0], x[1]+q[1], x[2]+q[2]) : 0);
c = a;
if((!a) === (!b)) {
c = 0;
} else if(!a) {
c = -b;
}
//If cell type doesn't match, start a new run
if(p !== c) {
runs[nr++] = x[u];
runs[nr++] = c;
}
}
//Add sentinel run
runs[nr++] = dims[u];
runs[nr++] = 0;
//Update frontier by merging runs
var fp = 0;
for(var i=0, j=0; i<nf && j<nr-2; ) {
var p = polygons[frontier[i]]
, p_l = p.left[p.left.length-1][0]
, p_r = p.right[p.right.length-1][0]
, p_c = p.color
, r_l = runs[j] //Start of run
, r_r = runs[j+2] //End of run
, r_c = runs[j+1]; //Color of run
//Check if we can merge run with polygon
if(r_r > p_l && p_r > r_l && r_c === p_c) {
//Merge run
p.merge_run(x[v], r_l, r_r);
//Insert polygon into frontier
next_frontier[fp++] = frontier[i];
++i;
j += 2;
} else {
//Check if we need to advance the run pointer
if(r_r <= p_r) {
if(!!r_c) {
var n_poly = new MonotonePolygon(r_c, x[v], r_l, r_r);
next_frontier[fp++] = polygons.length;
polygons.push(n_poly);
}
j += 2;
}
//Check if we need to advance the frontier pointer
if(p_r <= r_r) {
p.close_off(x[v]);
++i;
}
}
}
//Close off any residual polygons
for(; i<nf; ++i) {
polygons[frontier[i]].close_off(x[v]);
}
//Add any extra runs to frontier
for(; j<nr-2; j+=2) {
var r_l = runs[j]
, r_r = runs[j+2]
, r_c = runs[j+1];
if(!!r_c) {
var n_poly = new MonotonePolygon(r_c, x[v], r_l, r_r);
next_frontier[fp++] = polygons.length;
polygons.push(n_poly);
}
}
//Swap frontiers
var tmp = next_frontier;
next_frontier = frontier;
frontier = tmp;
nf = fp;
}
//Close off frontier
for(var i=0; i<nf; ++i) {
var p = polygons[frontier[i]];
p.close_off(dims[v]);
}
// --- Monotone subdivision of polygon is complete at this point ---
x[d]++;
//Now we just need to triangulate each monotone polygon
for(var i=0; i<polygons.length; ++i) {
var p = polygons[i]
, c = p.color
, flipped = false;
if(c < 0) {
flipped = true;
c = -c;
}
for(var j=0; j<p.left.length; ++j) {
left_index[j] = vertices.length;
var y = [0.0,0.0,0.0]
, z = p.left[j];
y[d] = x[d];
y[u] = z[0];
y[v] = z[1];
vertices.push(y);
}
for(var j=0; j<p.right.length; ++j) {
right_index[j] = vertices.length;
var y = [0.0,0.0,0.0]
, z = p.right[j];
y[d] = x[d];
y[u] = z[0];
y[v] = z[1];
vertices.push(y);
}
//Triangulate the monotone polygon
var bottom = 0
, top = 0
, l_i = 1
, r_i = 1
, side = true; //true = right, false = left
stack[top++] = left_index[0];
stack[top++] = p.left[0][0];
stack[top++] = p.left[0][1];
stack[top++] = right_index[0];
stack[top++] = p.right[0][0];
stack[top++] = p.right[0][1];
while(l_i < p.left.length || r_i < p.right.length) {
//Compute next side
var n_side = false;
if(l_i === p.left.length) {
n_side = true;
} else if(r_i !== p.right.length) {
var l = p.left[l_i]
, r = p.right[r_i];
n_side = l[1] > r[1];
}
var idx = n_side ? right_index[r_i] : left_index[l_i]
, vert = n_side ? p.right[r_i] : p.left[l_i];
if(n_side !== side) {
//Opposite side
while(bottom+3 < top) {
if(flipped === n_side) {
faces.push([ stack[bottom], stack[bottom+3], idx, c]);
} else {
faces.push([ stack[bottom+3], stack[bottom], idx, c]);
}
bottom += 3;
}
} else {
//Same side
while(bottom+3 < top) {
//Compute convexity
for(var j=0; j<2; ++j)
for(var k=0; k<2; ++k) {
delta[j][k] = stack[top-3*(j+1)+k+1] - vert[k];
}
var det = delta[0][0] * delta[1][1] - delta[1][0] * delta[0][1];
if(n_side === (det > 0)) {
break;
}
if(det !== 0) {
if(flipped === n_side) {
faces.push([ stack[top-3], stack[top-6], idx, c ]);
} else {
faces.push([ stack[top-6], stack[top-3], idx, c ]);
}
}
top -= 3;
}
}
//Push vertex
stack[top++] = idx;
stack[top++] = vert[0];
stack[top++] = vert[1];
//Update loop index
if(n_side) {
++r_i;
} else {
++l_i;
}
side = n_side;
}
}
}
}
return { vertices:vertices, faces:faces };
}
})();
Eif(exports) {
exports.mesher = MonotoneMesh;
}
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