public void drawSphere(
Coords center,
double radius,
int longitude,
double longitudeStart,
int longitudeLength,
double frustumRadius) {
manager.startGeometry(Manager.Type.TRIANGLES);
// set texture to (0,0)
manager.setDummyTexture();
int latitude = longitude / 4;
// check which parts are visible (latitudes)
Coords o = manager.getView3D().getCenter();
double z = center.getZ();
double zMin = o.getZ() - frustumRadius;
double zMax = o.getZ() + frustumRadius;
int latitudeMaxTop = 0;
latitudeMaxTop = latitude;
if (Kernel.isGreater(z + radius, zMax)) {
double angle = Math.asin((zMax - z) / radius);
latitudeMaxTop = (int) (latitude * 2 * angle / Math.PI) + 2;
}
int latitudeMaxBottom = 0;
latitudeMaxBottom = latitude;
if (Kernel.isGreater(zMin, z - radius)) {
double angle = Math.asin((z - zMin) / radius);
latitudeMaxBottom = (int) (latitude * 2 * angle / Math.PI) + 2;
}
// Log.debug(latitudeMaxBottom+","+latitudeMaxTop);
int latitudeMax = Math.max(latitudeMaxTop, latitudeMaxBottom);
int latitudeMin = 0; // start on equator
if (latitudeMaxTop < 0) { // start below equator
latitudeMin = -latitudeMaxTop;
} else if (latitudeMaxBottom < 0) { // start above equator
latitudeMin = -latitudeMaxBottom;
}
// check which parts are visible (longitudes)
// start drawing
if (coordsArray.length <= longitudeLength) {
coordsArray = new Coords[longitudeLength + 1];
for (int ui = 0; ui <= longitudeLength; ui++) {
coordsArray[ui] = new Coords(4);
}
}
Coords norm1 = new Coords(4), norm2 = new Coords(4), n1b = new Coords(4), n2b = new Coords(4);
double[] cosSinV = new double[2];
// equator
// cosSinV[0] = 1; // cos(0)
// cosSinV[1] = 0; // sin(0)
cosSin(latitudeMin, latitude, cosSinV);
double lastCos = 1;
for (int ui = 0; ui <= longitudeLength; ui++) {
sphericalCoords(ui, longitude, longitudeStart, cosSinV, coordsArray[ui]);
}
// shift for longitude
int shift = 1;
boolean jumpNeeded = false;
for (int vi = latitudeMin + 1; vi < latitudeMax; vi++) {
cosSin(vi, latitude, cosSinV);
// check if parallel is small enough to make jumps
if (2 * cosSinV[0] < lastCos) {
lastCos = lastCos / 2;
jumpNeeded = true;
} else {
jumpNeeded = false;
}
// first values
norm2.set(coordsArray[0]);
sphericalCoords(0, longitude, longitudeStart, cosSinV, n2b);
// first : no jump
boolean jump = jumpNeeded;
for (int ui = shift; ui <= longitudeLength; ui += shift) {
// last latitude values
norm1.set(norm2);
norm2.set(coordsArray[ui]);
// new latitude values and draw triangles
n1b.set(n2b);
if (jumpNeeded) {
if (jump) { // draw edge triangle and center triangle
sphericalCoords(ui + shift, longitude, longitudeStart, cosSinV, n2b);
if (vi < latitudeMaxTop) { // top triangles
drawNCr(norm1, center, radius);
drawNCr(norm2, center, radius);
drawNCr(n1b, center, radius);
drawNCr(n1b, center, radius);
drawNCr(norm2, center, radius);
drawNCr(n2b, center, radius);
}
if (vi < latitudeMaxBottom) { // bottom triangles
drawNCrm(norm1, center, radius);
drawNCrm(n1b, center, radius);
drawNCrm(norm2, center, radius);
drawNCrm(n1b, center, radius);
drawNCrm(n2b, center, radius);
drawNCrm(norm2, center, radius);
}
} else { // draw edge triangle
sphericalCoords(ui, longitude, longitudeStart, cosSinV, n2b);
if (vi < latitudeMaxTop) { // top triangles
drawNCr(norm1, center, radius);
drawNCr(norm2, center, radius);
drawNCr(n1b, center, radius);
}
if (vi < latitudeMaxBottom) { // bottom triangles
drawNCrm(norm1, center, radius);
drawNCrm(n1b, center, radius);
drawNCrm(norm2, center, radius);
}
}
} else { // no jump : draw two triangles
sphericalCoords(ui, longitude, longitudeStart, cosSinV, n2b);
if (vi < latitudeMaxTop) { // top triangles
drawNCr(norm1, center, radius);
drawNCr(norm2, center, radius);
drawNCr(n1b, center, radius);
drawNCr(norm2, center, radius);
drawNCr(n2b, center, radius);
drawNCr(n1b, center, radius);
}
if (vi < latitudeMaxBottom) { // bottom triangles
drawNCrm(norm1, center, radius);
drawNCrm(n1b, center, radius);
drawNCrm(norm2, center, radius);
drawNCrm(norm2, center, radius);
drawNCrm(n1b, center, radius);
drawNCrm(n2b, center, radius);
}
}
coordsArray[ui].set(n2b);
if (jumpNeeded) {
jump = !jump;
}
}
// if just jumps done, next shift is twice
if (jumpNeeded) {
shift = shift * 2;
}
sphericalCoords(0, longitude, longitudeStart, cosSinV, coordsArray[0]);
}
if (latitudeMax == latitude) {
// pole
norm2.set(coordsArray[0]);
for (int ui = shift; ui <= longitudeLength; ui += shift) {
norm1.set(norm2);
norm2.set(coordsArray[ui]);
if (latitudeMaxTop == latitude) { // top triangles
drawNCr(norm1, center, radius);
drawNCr(norm2, center, radius);
drawNCr(Coords.VZ, center, radius);
}
if (latitudeMaxBottom == latitude) { // bottom triangles
drawNCrm(norm1, center, radius);
drawNCrm(Coords.VZ, center, radius);
drawNCrm(norm2, center, radius);
}
}
}
manager.endGeometry();
}
/**
* draws normal and point at center - normal * radius
*
* @param normal
* @param center
* @param radius
*/
protected void drawNCrm(Coords normal, Coords center, double radius) {
normal2.setX(normal.getX());
normal2.setY(normal.getY());
normal2.setZ(-normal.getZ());
drawNCr(normal2, center, radius);
}