MATRIX3 TET::G()
{
VEC3F row[3];
row[0] = *(vertices[0]) - *(vertices[3]);
row[1] = *(vertices[1]) - *(vertices[3]),
row[2] = *(vertices[2]) - *(vertices[3]);
MATRIX3 T;
T << row[0][0], row[1][0], row[2][0],
row[0][1], row[1][1], row[2][1],
row[0][2], row[1][2], row[2][2];
return T.transpose().inverse();
}
int main(int argc, char **argv)
{
printf("Usage: computeFTLE flowmap.raw w h d RES\n");
int w = atoi(argv[2]),
h = atoi(argv[3]),
d = atoi(argv[4]);
float RES = atof(argv[5]);
printf("Opening file %s, w h d: %d %d %d\n", argv[1], w, h, d);
vector<VECTOR3> offset(w*h*d);
FILE *fp = fopen(argv[1], "rb");
fread(&offset[0], w*h*d, 12, fp);
fclose(fp);
if (0) // now we generate flowmap
{
int x,y,z, count=0;
for (z=0; z<d; z++)
for (y=0; y<h; y++)
for (x=0; x<w; x++) {
offset[count] = offset[count] + VECTOR3(x*RES, y*RES, z*RES);
//printf("offset: %f %f %f\n", offset[count][0], offset[count][1], offset[count][2]);
count ++;
}
}
// use osuflow
OSUFlow *osuflow = new OSUFlow();
float minB[3] = {0,0,0}, maxB[3];
maxB[0] = w-1; maxB[1] = h-1; maxB[2] = d-1;
osuflow->CreateStaticFlowField((float *)&offset[0], w, h, d, minB, maxB);
CVectorField *field = osuflow->GetFlowField();
// FTLE
vector<float> ftle(w*h*d);
int x,y,z, count=0;
for (z=0; z<d; z++)
{
for (y=0; y<h; y++)
for (x=0; x<w; x++)
{
MATRIX3 jac = field->Jacobian(VECTOR3(x,y,z)),
jsquare; // TODO: delta in Jac. computation
jac = jac * (1/RES);
jsquare = jac.transpose() * jac;
float m[3][3], eigenvalues[3];
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++) {
m[i][j] = jsquare(i, j);
}
}
compute_eigenvalues(m, eigenvalues);
float max_eig = max(eigenvalues[0], max(eigenvalues[1], eigenvalues[2]));
//printf("%f\n", max_eig);
ftle[count++] = log(max_eig)*.5;
}
printf("z=%d\n", z);
}
fp = fopen("ftle.raw", "wb");
fwrite(&ftle[0], w*h*d, sizeof(float), fp);
fclose(fp);
printf("output: ftle.raw\n");
return 0;
}
