projector.py

#!/usr/bin/env python2
# -*- coding: utf-8 -*-
"""
Created on Mon Jun 25 15:47:31 2018

@author: erick
"""

def isect_line_plane_v3(p0, p1, p_co, p_no, epsilon=1e-6):
    """
    p0, p1: define the line
    p_co, p_no: define the plane:
        p_co is a point on the plane (plane coordinate).
        p_no is a normal vector defining the plane direction;
             (does not need to be normalized).

    return a Vector or None (when the intersection can't be found).
    """

    u = sub_v3v3(p1, p0)
    dot = dot_v3v3(p_no, u)

    if abs(dot) > epsilon:
        # the factor of the point between p0 -> p1 (0 - 1)
        # if 'fac' is between (0 - 1) the point intersects with the segment.
        # otherwise:
        #  < 0.0: behind p0.
        #  > 1.0: infront of p1.
        w = sub_v3v3(p0, p_co)
        fac = -dot_v3v3(p_no, w) / dot
        u = mul_v3_fl(u, fac)
        return add_v3v3(p0, u)
    else:
        # The segment is parallel to plane
        return None

# ----------------------
# generic math functions

def add_v3v3(v0, v1):
    return (
        v0[0] + v1[0],
        v0[1] + v1[1],
        v0[2] + v1[2],
        )


def sub_v3v3(v0, v1):
    return (
        v0[0] - v1[0],
        v0[1] - v1[1],
        v0[2] - v1[2],
        )


def dot_v3v3(v0, v1):
    return (
        (v0[0] * v1[0]) +
        (v0[1] * v1[1]) +
        (v0[2] * v1[2])
        )


def len_squared_v3(v0):
    return dot_v3v3(v0, v0)


def mul_v3_fl(v0, f):
    return (
        v0[0] * f,
        v0[1] * f,
        v0[2] * f,
        )

test = [1.0, 1.00, 1.0]
norm = [0, 0, 1.0]
surf = [0,0,0]

print(isect_line_plane_v3([109,122,3.5],[0,0,1],surf,norm))