Realizzare una visualizzazione del vento, simile ad alcune apparse online per ogni uragano di recente.
JSL di seguito con i parametri abbassati per migliori prestazioni interattive.
Il modello utilizzato dal codice per il campo eolico è progettato per creare una bella visualizzazione e non rappresenta la realtà.
I vettori per il video hanno questo aspetto; la visualizzazione cambia quando si trascinano i vettori.
The script uses Mouse Trap to position the arrowsLo script utilizza Mouse Trap per posizionare le frecce
NTRAIL = 50; // <<< try 3 to 50 or so -- longer trail of fading dots
NPARTICLES = 1000; // try 100...10000. interacts with NBINS, need less bins with less particles
SLOWER=50; // try 20 to 200 or so, smaller divisor makes bigger steps -- interacts with smoothing that affects cornering ability
SMOOTHING = 9; // try 1..10 or so to smooth the corners; smaller is more accurate, larger is prettier
NBINS=15; // try 2 to 19 or so. determines the granularity of the spawning locations where low densities are found
WINDFIELDSIZE = 40; // granularity of field, interacts with smoothing
PARTICLESIZE = 1; // try 0..10 or so may affect rendering speed
FADEPOWER = 1.5; // power tweaks fade curve
FADEMIN=20/255; // bottom end of fade curve 1..FADEMIN - darkest color that displays
graphxsize=1920/2;
graphysize=1080/2;
//outdir="F:\weather\windfieldpics\";
//==================
// flow visualization -- make a wind field
dx = J( WINDFIELDSIZE, WINDFIELDSIZE, 0 );
dy = J( WINDFIELDSIZE, WINDFIELDSIZE, 0 );
Parallel Assign( {SLOWER=SLOWER}, dx[r( -1, 1 ), c( -1, 1 )] = Sin( r ) / SLOWER );
Parallel Assign( {SLOWER=SLOWER}, dy[r( -1, 1 ), c( -1, 1 )] = Sin( c ) / SLOWER ); //
windlist = {{{0.171875, 0.0458333333333334}, {0.15125, -0.715}}, {{0.171875, -0.9075},
{0.763125, -0.348333333333333}}, {{-0.859375, -0.504166666666667}, {-0.1925, -0.9075
}}, {{-0.385, 0.889166666666667}, {-0.955625, 0.119166666666667}}, {{0.78375, -0.165
}, {0.268125, 0.128333333333333}}, {{-0.240625, 0.0458333333333334}, {-0.78375,
-0.22}}, {{0.86625, -0.0183333333333333}, {0.2475, 0.8525}}, {{-0.144375,
-0.705833333333333}, {-0.2475, -0.0641666666666667}}};
/*
{
{{.10,.20},{.50,.30}},
{{.20,.20},{.50,.40}},
{{.30,.20},{.50,.50}},
{{.40,.20},{.50,.60}},
{{.50,.20},{.50,.70}},
{{.60,.20},{.50,.80}},
{{.70,.20},{.50,.90}}
};
*/
caprow=.;
capcol=.;
ReleaseFunction = Function( {x, y},
{},
caprow = capcol = .;
// put the wind vectors into the dx/dy matrices
Parallel Assign(
{SLOWER = SLOWER, windlist = windlist},
dx[r( -1, 1 ), c( -1, 1 )] = (x = 0 ; totalscale = 0 ; For( iwind = 1, iwind <= N Items( windlist ), iwind += 1,
cx = (windlist[iwind][1][1] + windlist[iwind][2][1]) / 2;
cy = (windlist[iwind][1][2] + windlist[iwind][2][2]) / 2;
dx = windlist[iwind][2][1] - windlist[iwind][1][1]; // positive toward arrow
scale = 1 / (Sqrt( (c - cx) ^ 2 + (r - cy) ^ 2 ) + .001);
totalscale += scale;
x += dx * scale;
) ; x / totalscale / SLOWER)
);
Parallel Assign(
{SLOWER = SLOWER, windlist = windlist},
dy[r( -1, 1 ), c( -1, 1 )] = (y = 0 ; totalscale = 0 ; For( iwind = 1, iwind <= N Items( windlist ), iwind += 1,
cx = (windlist[iwind][1][1] + windlist[iwind][2][1]) / 2;
cy = (windlist[iwind][1][2] + windlist[iwind][2][2]) / 2;
dy = windlist[iwind][2][2] - windlist[iwind][1][2]; // positive toward arrow
scale = 1 / (Sqrt( (c - cx) ^ 2 + (r - cy) ^ 2 ) + .001);
totalscale += scale;
y += dy * scale;
) ; y / totalscale / SLOWER)
);
);
ReleaseFunction(0,0);
New Window( "Example",
Graph Box(
X Scale( -1.1, 1.1 ),
Y Scale( -1.1, 1.1 ),
Pen Size( 4 );
For( iwind = 1, iwind <= N Items( windlist ), iwind += 1,
Arrow( windlist[iwind][1], windlist[iwind][2] )
);
Mousetrap(
Function( {x, y},
{irow, nearrow = ., icol, nearcol = ., dist, neardist = 1e9},
If( Is Missing( caprow ),
For( irow = 1, irow <= N Items( windlist ), irow += 1,
For( icol = 1, icol <= 2, icol += 1,
dist = Sqrt( (windlist[irow][icol][1] - x) ^ 2 + (windlist[irow][icol][2] - y) ^ 2 );
If( dist < neardist,
nearrow = irow;
nearcol = icol;
neardist = dist;
);
)
);
If( !Is Missing( nearrow ),
caprow = nearrow;
capcol = nearcol;
);
);
If( !Is Missing( caprow ) & !Is Missing( capcol ),
windlist[caprow][capcol][1] = x;
windlist[caprow][capcol][2] = y;
);
)//move
, //
ReleaseFunction(x,y)//release
);
)
);
// ===============================
SPREAD=1/NBINS; // mu for random normal spawn location
density = J( NBINS, NBINS, 0 );
//density[1, 1] = 1; // first loc max needs something to work with
_DX_ = 1;
_DY_ = 2;
_COLOR_ = 3;
_TRAILIDX_ = 4;
_TRAIL_ = 5; // NTRAIL begins here
_X_ = _TRAIL_;
_Y_ = _TRAIL_ + 1;
OUTOFPLAY = 99; // well beyond the graph's edge
DFRACTION=SMOOTHING;
NFRACTION = DFRACTION-1;
tran = J( NTRAIL, 1, 0 );
Parallel Assign( {FADEPOWER=FADEPOWER,FADEMIN=FADEMIN^(1/FADEPOWER)}, tran[r( 1, FADEMIN ), c] = r ^ FADEPOWER );
_STRAIL_ = 2; // stride x y pairs
particles = J( NPARTICLES , _TRAIL_ - 1 + _STRAIL_ * NTRAIL, OUTOFPLAY ); // dx,dy,color,xy trail has alpha fade
particles[0, _DX_] = 0;
particles[0, _DY_] = 0;
particles[0, _TRAILIDX_] = NTRAIL; // used to fade in, fade out
ExpectedParticlesPerBin = NPARTICLES/nitems(density);
New Window( "Example",
g = Graph Box(
Frame Size( graphxsize, graphysize ),
X Scale( -1.1, 1.1 ),
Y Scale( -1.1, 1.1 ),
suppressaxes,
<<MARKER size=""> NTRAIL, // point is in the fading sequence
// shift old particles out
particles[i, (_TRAIL_ + (_STRAIL_ * 1)) :: (_TRAIL_ + _STRAIL_ * (NTRAIL) - 1)] = particles[i, (_TRAIL_ + (_STRAIL_ * 0)) :: (_TRAIL_ + _STRAIL_ * (NTRAIL - 1) - 1)];
nn = (particles[i, _TRAILIDX_] -= 1); // counting time while previous point fades away
If( nn == NTRAIL, // restart this completely faded point
rr = Random Integer( 1, N Rows( minDenXLocs ) );
tx = particles[i, _X_ + _STRAIL_ * (NTRAIL - 1)] = Max( -.999, Min( .999, Random Normal( minDenXLocs[rr], SPREAD ) ) ); // next to last
ty = particles[i, _Y_ + _STRAIL_ * (NTRAIL - 1)] = Max( -.999, Min( .999, Random Normal( minDenYLocs[rr], SPREAD ) ) );
// index to field data
idx = 1 + Round( (N Cols( dx ) - 1) * ((tx + 1) / 2) ); // tx+1 is 0...2
idy = 1 + Round( (N Rows( dx ) - 1) * ((ty + 1) / 2) ); // divide by 2 is 0...1 becomes 0..nr-1...round, +1 becomes 1...nr
particles[i, _DX_] = dx[idy, idx]; // dx,dy is the field speed. init the particles DX,DY
particles[i, _DY_] = dy[idy, idx]; // to the correct value
// the values just stored at NTRAIL-2 will display, slightly bright, on this cycle
// and move to NTRAIL-1 (dimmest) on next cycle
);//
, /* elseif */ fadeIdx >= 1, // point is in the start sequence, or started
If( fadeIdx > 1, // still fading in
(particles[i, _TRAILIDX_] -= 1);// for next round
particles[i, (_X_ :: _Y_) + _STRAIL_ * (fadeIdx - 2)] = particles[i, (_X_ :: _Y_) + _STRAIL_ * (fadeIdx-1)] + particles[i, _DX_::_DY_];
,// else...sticks at 1
// shift old particles out
particles[i, (_TRAIL_ + (_STRAIL_ * 1)) :: (_TRAIL_ + _STRAIL_ * (NTRAIL) - 1)] = particles[i, (_TRAIL_ + (_STRAIL_ * 0)) :: (_TRAIL_ + _STRAIL_ * (NTRAIL - 1) - 1)];
particles[i, (_X_ :: _Y_) + _STRAIL_ * (fadeIdx - 1)] = particles[i, (_X_ :: _Y_) + _STRAIL_ * (fadeIdx-0)] + particles[i, _DX_::_DY_];
);
If(
!(-1 < particles[i, _X_ + _STRAIL_ * (fadeIdx - 1)] < 1) | !(-1 < particles[i, _Y_ + _STRAIL_ * (fadeIdx - 1)] < 1) |
Sqrt( particles[i, _DX_] ^ 2 + particles[i, _DY_] ^ 2 ) < .0001,
// fix up particles leaving graph
// leaving because a 99,99 was incremented by dx/dy
particles[i, _TRAILIDX_] = 2 * NTRAIL;// enter fade-out sequence
particles[i, _X_ + _STRAIL_ * (1 - 1)] = OUTOFPLAY;
particles[i, _Y_ + _STRAIL_ * (1 - 1)] = OUTOFPLAY;
particles[i, _DX_] = 0;
particles[i, _DY_] = 0; //
, // else
// index to field data
idx = 1 + Round( (N Cols( dx ) - 1) * ((particles[i, _X_ + _STRAIL_ * (fadeIdx - 1)] + 1) / 2) );
idy = 1 + Round( (N Rows( dx ) - 1) * ((particles[i, _Y_ + _STRAIL_ * (fadeIdx - 1)] + 1) / 2) );
// new deltas based on nearest field delta
particles[i, _DX_] = (NFRACTION * particles[i, _DX_] + dx[idy, idx]) / DFRACTION;
particles[i, _DY_] = (NFRACTION * particles[i, _DY_] + dy[idy, idx]) / DFRACTION;
// nearest density bin...increment
yyy = 1 + Round( (N Rows( density ) - 1) * ((particles[i, _Y_ + _STRAIL_ * (fadeIdx - 1)] + 1) / 2) );
xxx = 1 + Round( (N Cols( density ) - 1) * ((particles[i, _X_ + _STRAIL_ * (fadeIdx - 1)] + 1) / 2) );
q=((density[yyy, xxx] += 1))/ExpectedParticlesPerBin;
if( q*randomuniform()>2,
particles[i, _TRAILIDX_] = 2 * NTRAIL;// enter fade-out sequence
particles[i, _X_ + _STRAIL_ * (1 - 1)] = OUTOFPLAY;
particles[i, _Y_ + _STRAIL_ * (1 - 1)] = OUTOFPLAY;
particles[i, _DX_] = 0;
particles[i, _DY_] = 0; //
);
);//
, // else bad _TRAILIDX_
Throw( "???" )
);
);
For( i = NTRAIL, i >= 1, i -= 1,
Transparency( tran[i] );
Marker( Color State( "white" ), particles[0, _X_ + _STRAIL_ * (i - 1)],/*flip -*/ particles[0, _Y_ + _STRAIL_ * (i - 1)] );
);
)
);
wait(.01);
picno = 1e6;
while(1, g << inval<<UPDATEWINDOW></UPDATEWINDOW></MARKER>
