/**
* Set the view matrix `s' is the scaling factor of translating real coordinates to the screen
* coordinates (x0, y0) the screen coordinates of the center
*/
void setMatrix(Matrix3D viewMat, double s, double x0, double y0) {
mat.unit();
mat.mult(viewMat);
mat.scale(s, s, s);
real2Screen = s;
mat.translate(x0, y0, 0);
transformed = false;
}
public void mouseDragged(MouseEvent e) {
int x = e.getX();
int y = e.getY();
tmpMatrix.unit();
tmpMatrix.xrot(360.0 * (mouseY - y) / getSize().height);
tmpMatrix.yrot(360.0 * (x - mouseX) / getSize().width);
viewMatrix.mult(tmpMatrix);
repaint();
mouseX = x;
mouseY = y;
e.consume();
}
/** Compute the Z-order */
void getZOrder() {
// transform the coordinates
if (!transformed) {
mat.transform(realXYZ, screenXYZ, np);
transformed = true;
}
// bubble sort z-order
// zOrder[0] is the fartherest from the viewer
// zOrder[np - 1] is the nearest to the viewer
for (int i = 0; i < np; i++) zOrder[i] = i;
for (int i = 0; i < np; i++) {
// find the particle with the smallest z
int jm = i, k;
for (int j = i + 1; j < np; j++)
if (screenXYZ[zOrder[j]][2] < screenXYZ[zOrder[jm]][2]) jm = j;
if (jm != i) {
k = zOrder[i];
zOrder[i] = zOrder[jm];
zOrder[jm] = k;
}
}
}