How to use

dot

method

in

com.ardor3d.math.Vector4

/**
 * @param vec
 * @return the dot product of this vector with the x, y, z, w values of the given vector.
 * @throws NullPointerException
 *             if vec is null.
 */
@Override
public double dot(final ReadOnlyVector4 vec) {
  return dot(vec.getX(), vec.getY(), vec.getZ(), vec.getW());
}

/**
 * @param vec
 * @return the dot product of this vector with the x, y, z, w values of the given vector.
 * @throws NullPointerException
 *             if vec is null.
 */
@Override
public double dot(final ReadOnlyVector4 vec) {
  return dot(vec.getX(), vec.getY(), vec.getZ(), vec.getW());
}

@Test
public void testDot() {
  final Vector4 vec1 = new Vector4(7, 2, 5, -1);
  assertTrue(35.0 == vec1.dot(3, 1, 2, -2));
  assertTrue(-11.0 == vec1.dot(new Vector4(-1, 1, -1, 1)));
}

private void modifyProjectionMatrix(final Vector4 clipPlane) {
  // Get the current projection matrix
  projectionMatrix = cam.getProjectionMatrix().toArray(projectionMatrix);
  // Get the inverse transpose of the current modelview matrix
  final ReadOnlyMatrix4 modelViewMatrixInvTrans = tRenderer.getCamera().getModelViewMatrix().invert(tmpMatrix)
      .transposeLocal();
  modelViewMatrixInvTrans.applyPre(clipPlane, clipPlane);
  // Calculate the clip-space corner point opposite the clipping plane
  // as (sgn(clipPlane.x), sgn(clipPlane.y), 1, 1) and
  // transform it into camera space by multiplying it
  // by the inverse of the projection matrix
  cornerPoint.setX((sign(clipPlane.getX()) + projectionMatrix[8]) / projectionMatrix[0]);
  cornerPoint.setY((sign(clipPlane.getY()) + projectionMatrix[9]) / projectionMatrix[5]);
  cornerPoint.setZ(-1.0);
  cornerPoint.setW((1.0 + projectionMatrix[10]) / projectionMatrix[14]);
  // Calculate the scaled plane vector
  final Vector4 scaledPlaneVector = clipPlane.multiply((2.0 / clipPlane.dot(cornerPoint)), cornerPoint);
  // Replace the third row of the projection matrix
  projectionMatrix[2] = scaledPlaneVector.getX();
  projectionMatrix[6] = scaledPlaneVector.getY();
  projectionMatrix[10] = scaledPlaneVector.getZ() + 1.0;
  projectionMatrix[14] = scaledPlaneVector.getW();
  // Load it back into OpenGL
  final Matrix4 newProjectionMatrix = tmpMatrix.fromArray(projectionMatrix);
  tRenderer.getCamera().setProjectionMatrix(newProjectionMatrix);
}

private void modifyProjectionMatrix(final Vector4 clipPlane) {
  // Get the current projection matrix
  projectionMatrix = cam.getProjectionMatrix().toArray(projectionMatrix);
  // Get the inverse transpose of the current modelview matrix
  final ReadOnlyMatrix4 modelViewMatrixInvTrans = tRenderer.getCamera().getViewMatrix().invert(tmpMatrix)
      .transposeLocal();
  modelViewMatrixInvTrans.applyPre(clipPlane, clipPlane);
  // Calculate the clip-space corner point opposite the clipping plane
  // as (sgn(clipPlane.x), sgn(clipPlane.y), 1, 1) and
  // transform it into camera space by multiplying it
  // by the inverse of the projection matrix
  cornerPoint.setX((sign(clipPlane.getX()) + projectionMatrix[8]) / projectionMatrix[0]);
  cornerPoint.setY((sign(clipPlane.getY()) + projectionMatrix[9]) / projectionMatrix[5]);
  cornerPoint.setZ(-1.0);
  cornerPoint.setW((1.0 + projectionMatrix[10]) / projectionMatrix[14]);
  // Calculate the scaled plane vector
  final Vector4 scaledPlaneVector = clipPlane.multiply((2.0 / clipPlane.dot(cornerPoint)), cornerPoint);
  // Replace the third row of the projection matrix
  projectionMatrix[2] = scaledPlaneVector.getX();
  projectionMatrix[6] = scaledPlaneVector.getY();
  projectionMatrix[10] = scaledPlaneVector.getZ() + 1.0;
  projectionMatrix[14] = scaledPlaneVector.getW();
  // Load it back into OpenGL
  final Matrix4 newProjectionMatrix = tmpMatrix.fromArray(projectionMatrix);
  tRenderer.getCamera().setProjectionMatrix(newProjectionMatrix);
}