Interesting alternative. It cannot be performed by surface() but it can be
done in user space with polyhedron().
data = [ for(a=[0:10:360])
[ for(b=[0:10:360])
cos(a-b)+4*sin(a+b)+(a+b)/40 ]
];
surfaceData(data, center=true);
cube();
// operate like the builtin module surface() but
// from a matrix of floats instead of a text file
module surfaceData(M, center=false, convexity=10){
n = len(M);
m = len(M[0]);
miz = min([for(Mi=M) min(Mi)]);
minz = miz<0? miz-1 : -1;
ctr = center ? [-(m-1)/2, -(n-1)/2, 0]: [0,0,0];
points = [ // original data points
for(i=[0:n-1])for(j=[0:m-1]) [j, i, M[i][j]] +ctr,
[ 0, 0, minz ] + ctr,
[ m-1, 0, minz ] + ctr,
[ m-1, n-1, minz ] + ctr,
[ 0, n-1, minz ] + ctr,
// additional interpolated points
// the points bellow with undef coordinates are not used by
faces
for(i=[0:n-1])for(j=[0:m-1])
let( med = (M[i][j]+M[i+1][j]+M[i+1][j+1]+M[i][j+1])/4 )
[j+0.5, i+0.5, med] + ctr
];
faces = [ // faces connecting data points to interpolated ones
for(i=[0:n-2])
for(j=[im:im+m-2])
each [ [ j+1, j, j+nm+4 ],
[ j, j+m, j+nm+4 ],
[ j+m, j+m+1, j+nm+4 ],
[ j+m+1, j+1, j+nm+4 ] ] ,
// lateral and bottom faces
[ for(i=[0:m-1]) i, nm+1, nm ],
[ for(i=[m-1:-1:0]) -m+i+nm, nm+3, nm+2 ],
[ for(i=[n-1:-1:0]) im, nm, nm+3 ],
[ for(i=[0:n-1]) im+m-1, nm+2, nm+1 ],
[nm, nm+1, nm+2, n*m+3 ]
];
polyhedron(points, faces, convexity);
}
Em qui, 4 de jul de 2019 às 17:16, Ari Diacou ari.diacou@gmail.com
escreveu:
