public void updateDrawData() {
mBGStarPositionsBuffer.position(0);
mBGStarColorsBuffer.position(0);
mBGStarTexturesBuffer.position(0);
// Update the star data
for (Star star : BGStarSet) {
Geocentric position = star.getCoords();
Geocentric u = MathUtils.normalize(MathUtils.crossProduct(position, Z_UP_VECTOR));
Geocentric v = MathUtils.crossProduct(u, position);
float sizer = star.magnitude * mRenderer.mPointSizeFactor;
Geocentric sized_u = new Geocentric(u.x * sizer, u.y * sizer, u.z * sizer);
Geocentric sized_v = new Geocentric(v.x * sizer, v.y * sizer, v.z * sizer);
float[] bottomLeft = {
position.x - sized_u.x - sized_v.x,
position.y - sized_u.y - sized_v.y,
position.z - sized_u.z - sized_v.z
};
float[] topLeft = {
position.x - sized_u.x + sized_v.x,
position.y - sized_u.y + sized_v.y,
position.z - sized_u.z + sized_v.z
};
float[] bottomRight = {
position.x + sized_u.x - sized_v.x,
position.y + sized_u.y - sized_v.y,
position.z + sized_u.z - sized_v.z
};
float[] topRight = {
position.x + sized_u.x + sized_v.x,
position.y + sized_u.y + sized_v.y,
position.z + sized_u.z + sized_v.z
};
// Inserting first triangle (counter-clockwise)
mBGStarPositionsBuffer.put(topLeft);
mBGStarPositionsBuffer.put(bottomLeft);
mBGStarPositionsBuffer.put(topRight);
// Inserting second triangle (counter-clockwise)
mBGStarPositionsBuffer.put(bottomLeft);
mBGStarPositionsBuffer.put(bottomRight);
mBGStarPositionsBuffer.put(topRight);
// Inserting Color per Star (white)
mBGStarColorsBuffer.put(STAR_COLOR_DATA_ARRAY);
// Inserting Texture Coordinates per Star
mBGStarTexturesBuffer.put(TEX_COORD_ARRAY);
}
mBGStarPositionsBuffer.position(0);
mBGStarColorsBuffer.position(0);
mBGStarTexturesBuffer.position(0);
}
private void changeMapX(float radians) {
Geocentric lookVector = mUser.getLookDir();
Geocentric crossVector = MathUtils.crossProduct(lookVector, mUser.getLookNormal());
Geocentric deltaLookVector =
new Geocentric(crossVector.x * radians, crossVector.y * radians, crossVector.z * radians);
Geocentric newLookDir = MathUtils.add(lookVector, deltaLookVector);
newLookDir = MathUtils.normalize(newLookDir);
mUser.setLookDir(newLookDir);
}