Pendulum::PolyChain
Pendulum::positions() const
{
PolyChain result(weightCnt());
result[0] = math::float2(deflection(0), 0);
for (int i = 1; i < weightCnt(); ++i)
{
float const dySq = m_lengthSq
- math::sq(deflection(i) - deflection(i - 1));
float const dy = dySq <= 0.0f ? 0.0f : std::sqrt(dySq);
result[i] = math::float2(
deflection(i),
result[i - 1].y + dy
);
}
return result;
}
/*
* map() maps a M2 x M1 source image fsource[i][j] onto an N2 x N1 target
* image ftarget[i][j] with the mapping
* ftarget(r) += fsource(r + d)
* where the deflection d = (di, dj) is supplied by function deflection()
*
* we use the slightly confusing notation (i,j) -> (y, x)
*/
void map(float **ftarget, int N1, int N2, float **fsource, int M1, int M2,
int (*deflection)(float ri, float rj, float *di, float *dj))
{
int i, j, index, goodtriangle;
float di, dj;
vert *point[3], *basevert;
/* set source image globals */
gfsource = fsource;
gftarget = ftarget;
gM1 = M1;
gM2 = M2;
for (i = 0; i < N2; i++) {
gtargeti = i;
for (j = 0; j < N1; j++) {
gtargetj = j;
gfsum = gareasum = 0.0;
/* do the upper triangle */
point[0] = makevertex(j, i + 1);
point[1] = makevertex(j + 1, i + 1);
point[2] = makevertex(j + 1, i);
goodtriangle = 1;
for (index = 0; index < 3; index++) {
goodtriangle *= deflection(point[index]->y,
point[index]->x, &di, &dj);
point[index]->y += di;
point[index]->x += dj;
}
if (goodtriangle) {
makering(&basevert, point, 3);
if (globalmapmode == INVERSEMAPMODE) {
garea = trianglearea(basevert);
}
decompose(basevert);
}
/* do the lower triangle */
point[0] = makevertex(j, i + 1);
point[1] = makevertex(j, i);
point[2] = makevertex(j + 1, i);
goodtriangle = 1;
for (index = 0; index < 3; index++) {
goodtriangle *= deflection(point[index]->y,
point[index]->x, &di, &dj);
point[index]->y += di;
point[index]->x += dj;
}
if (goodtriangle) {
makering(&basevert, point, 3);
if (globalmapmode == INVERSEMAPMODE) {
garea = trianglearea(basevert);
}
decompose(basevert);
}
/* now add the pixel value */
if ((gareasum > 0.0) && (globalmapmode == FORWARDMAPMODE)) {
ftarget[i][j] = gfsum / gareasum;
}
freeverts();
}
}
}
/* scroll of deflection */
void i_deflect(pob o)
{
if (o->blessing > -1)
Objects[o->id].known = 1;
deflection(o->blessing);
}
