// To write an X3DOM-compatible scene file, we cannot include
// LineProperties nodes.
void X3DOMDisplayDevice::text(float *pos, float size, float thickness,
const char *str) {
float textpos[3];
float textsize;
hersheyhandle hh;
// transform the world coordinates
(transMat.top()).multpoint3d(pos, textpos);
textsize = size * 1.5f;
ResizeArray<int> idxs;
ResizeArray<float> pnts;
idxs.clear();
pnts.clear();
int idx=0;
while (*str != '\0') {
float lm, rm, x, y;
int draw;
x=y=0.0f;
draw=0;
hersheyDrawInitLetter(&hh, *str, &lm, &rm);
textpos[0] -= lm * textsize;
while (!hersheyDrawNextLine(&hh, &draw, &x, &y)) {
float pt[3];
if (draw) {
// add another connected point to the line strip
idxs.append(idx);
pt[0] = textpos[0] + textsize * x;
pt[1] = textpos[1] + textsize * y;
pt[2] = textpos[2];
pnts.append(pt[0]);
pnts.append(pt[1]);
pnts.append(pt[2]);
idx++;
} else {
idxs.append(-1); // pen-up, end of the line strip
}
}
idxs.append(-1); // pen-up, end of the line strip
textpos[0] += rm * textsize;
str++;
}
fprintf(outfile, "<Shape>\n");
fprintf(outfile, " ");
//
// Emit the line properties
//
fprintf(outfile, "<Appearance><Material ");
fprintf(outfile, "ambientIntensity='%g' ", mat_ambient);
fprintf(outfile, "diffuseColor='0 0 0' ");
const float *rgb = matData[colorIndex];
fprintf(outfile, "emissiveColor='%g %g %g' ",
mat_diffuse * rgb[0], mat_diffuse * rgb[1], mat_diffuse * rgb[2]);
fprintf(outfile, "/>");
#if 0
// XXX X3DOM v1.1 doesn't handle LineProperties nodes
// emit a line thickness directive, if needed
if (thickness < 0.99f || thickness > 1.01f) {
fprintf(outfile, " <LineProperties linewidthScaleFactor=\"%g\" "
"containerField=\"lineProperties\"/>\n",
(double) thickness);
}
#endif
fprintf(outfile, "</Appearance>\n");
//
// Emit the line set
//
fprintf(outfile, " <IndexedLineSet coordIndex='");
int i, cnt;
cnt = idxs.num();
for (i=0; i<cnt; i++) {
fprintf(outfile, "%d ", idxs[i]);
}
fprintf(outfile, "'>\n");
fprintf(outfile, " <Coordinate point='");
cnt = pnts.num();
for (i=0; i<cnt; i+=3) {
fprintf(outfile, "%c%g %g %g",
(i==0) ? ' ' : ',',
pnts[i], pnts[i+1], pnts[i+2]);
}
fprintf(outfile, "'/>\n");
fprintf(outfile, " </IndexedLineSet>\n");
fprintf(outfile, "</Shape>\n");
}
// draw a 3-D field lines that follow the volume gradient
void
DrawMolItem::draw_volume_field_lines (int volid, float seedval, float minlen,
float maxlen, float thickness)
{
const VolumetricData * v = NULL;
v = mol->get_volume_data (volid);
int printdonemesg = 0;
if (v == NULL)
{
msgInfo << "No volume data loaded at index " << volid << sendmsg;
return;
}
int seedcount = 0;
int pointcount = 0;
int totalpointcount = 0;
int usecolor;
ResizeArray<float> seeds;
append (DMATERIALOFF);
usecolor = draw_volume_get_colorid ();
cmdColorIndex.putdata (usecolor, cmdList);
seedcount = calcseeds_gradient_magnitude (v, &seeds, seedval * 0.5f,
seedval * 1.5f);
// Integrate field lines starting with each of the seeds to simulate
// particle advection.
// Uses Euler's approximation for solving the initial value problem.
// We could get a more accurate solution using a fourth order Runge-Kutta
// method, but with more math per iteration. We may want to implement
// the integrator as a user selected option.
// The choice of integration step size is currently arbitrary,
// but will become a user-defined parameter, since it affects speed
// and accuracy. A good default might be 0.25 times the smallest
// grid cell spacing axis.
float lx, ly, lz;
v->cell_lengths (&lx, &ly, &lz);
float mincelllen = lx;
mincelllen = (mincelllen < ly) ? mincelllen : ly;
mincelllen = (mincelllen < lz) ? mincelllen : lz;
float delta = mincelllen * 0.25f; // delta per step (compensates gradient magnitude)
// minimum gradient magnitude, before we consider that we've found
// a critical point in the dataset.
float mingmag = 0.0001f;
// max gradient magnitude, before we consider it a source/sink
float maxgmag = 5;
ResizeArray<float> points;
// For each seed point, integrate in both positive and
// negative directions for a field line length up to
// the maxlen criterion.
msgtimer *msgt = msg_timer_create (1);
int seed;
for (seed = 0; seed < seedcount; seed++)
{
// emit UI messages as integrator runs, for long calculations...
if (!(seed & 7) && msg_timer_timeout (msgt))
{
char tmpbuf[128];
sprintf (tmpbuf, "%6.2f %% complete",
(100.0f * seed) / (float) seedcount);
msgInfo << "integrating " << seedcount << " field lines: " << tmpbuf
<< sendmsg;
printdonemesg = 1;
}
int direction;
for (direction = -1; direction != 1; direction = 1)
{
float pos[3], comsum[3];
vec_copy (pos, &seeds[seed * 3]); // integration starting point is the seed
// init the arrays
points.clear ();
// main integration loop
pointcount = 0;
totalpointcount++;
float len = 0;
int iterations = 0;
float dir = (float) direction;
vec_zero (comsum); // clear center of mass accumulator
while ((len < maxlen) && (totalpointcount < 100000000))
{
float grad[3];
// sample gradient at the current position
v->voxel_gradient_interpolate_from_coord (pos, grad);
// Early-exit if we run out of bounds (gradient returned will
// be a vector of NANs), run into a critical point (zero gradient)
// or a huge gradient at a source/sink point in the dataset.
float gmag = norm (grad);
if (gmag < mingmag || gmag > maxgmag)
break;
// Draw the current point only after the gradient value
// has been checked, so we don't end up with out-of-bounds
// vertices.
// Only emit a fraction of integration points for display since
// the integrator stepsize needs to be small for more numerical
// accuracy, but the field lines themselves can be well
// represented with fewer sample points.
if (!(iterations & 1))
{
// Add a vertex for this field line
points.append (pos[0]);
points.append (pos[1]);
points.append (pos[2]);
vec_incr (comsum, pos);
pointcount++;
totalpointcount++;
}
// adjust integration stepsize so we never move more than
// the distance specified by delta at each step, to compensate
// for varying gradient magnitude
vec_scaled_add (pos, dir * delta / gmag, grad); // integrate position
len += delta; // accumulate distance
iterations++;
}
int drawfieldline = 1;
// only draw the field line for this seed if we have enough points.
// If we haven't reached the minimum field line length, we'll
// drop the whole field line.
if (pointcount < 2 || len < minlen)
drawfieldline = 0;
// only draw if bounding sphere diameter exceeds minlen
if (drawfieldline)
{
float com[3];
vec_scale (com, 1.0f / (float) pointcount, comsum);
float minlen2 = minlen * minlen;
drawfieldline = 0;
int p;
for (p = 0; p < pointcount; p++)
{
if ((2.0f * distance2 (com, &points[p * 3])) > minlen2)
{
drawfieldline = 1;
break;
}
}
}
// only draw the field line if it met all selection criteria
if (drawfieldline)
{
cmdLineType.putdata (SOLIDLINE, cmdList);
cmdLineWidth.putdata ((int) thickness, cmdList);
cmdColorIndex.putdata (usecolor, cmdList);
DispCmdPolyLineArray cmdPolyLineArray;
cmdPolyLineArray.putdata (&points[0], pointcount, cmdList);
}
}
}
msg_timer_destroy (msgt);
if (printdonemesg)
msgInfo << "field line integration complete." << sendmsg;
}