SideBySideFisheyeProjection.py 文件源码

def angular_position(texcoord):
    up = texcoord[0]
    v = texcoord[1]
    # correct for hemisphere
    if up>=0.5:
      u = 2.0*(up-0.5)
    else:
      u = 2.0*up

    # ignore points outside of circles
    if ((u-0.5)*(u-0.5) + (v-0.5)*(v-0.5))>0.25:
      return None, None

    # v: 0..1-> vp: -1..1
    phi = math.asin(2.0*(v-0.5))

    # u = math.cos(phi)*math.cos(theta)
    # u: 0..1 -> upp: -1..1
    u = 1.0-u
    theta = math.acos( 2.0*(u-0.5) / math.cos(phi) )

    if up<0.5:
       theta = theta-math.pi

    return (theta,phi)