#=====================
# shoot.py
#
# This script places a "hitspot" object where
# a ray sensor hits a face, oriented along
# the face normal, then it handles shooting.
#
# Randall Rickert
# randall@blender.nl
#=====================

from math import sqrt

#=====================
# Functions
#
# These first 3 are standard vector math
# (if used a lot, might be faster in C).
#=====================
def normalize(x): 
	length = sqrt(x[0]*x[0]+x[1]*x[1]+x[2]*x[2])
	return [x[0]/length,x[1]/length,x[2]/length]

def cross(x,y):
	return  [ x[1]*y[2] - x[2]*y[1],
			 x[2]*y[0] - x[0]*y[2],
			 x[0]*y[1] - x[1]*y[0]]

def dot(x,y):
	return x[0]*y[0] + x[1]*y[1]+x[2]*y[2]

def mul(s,x):
	return [s*x[0],s*x[1],s*x[2]]

#=====================
# Given any two vectors, vecToMat3 will return
# a 3x3 matrix having z aligned to the first
# vector and y tracking as near as possible
# to the second.
#=====================
def vecToMat3(vec, track):
	z = normalize(vec)
	dotprod = dot(z, normalize(track))

	if abs(dotprod) == 1: #prevent gimbol lock
		track.append(track[0])
		del track[0]

	x = normalize(cross(track, vec))
	y = cross(z, x)

	return [
		[x[0],y[0],z[0]],
		[x[1],y[1],z[1]],
		[x[2],y[2],z[2]]]

#=====================
# Game logic
#=====================

controller = GameLogic.getCurrentController()
raySensor = controller.getSensor("raySensor")
hitspot = controller.getOwner()
addFlash = controller.getActuator("addFlash")
addMark = controller.getActuator("addMark")

if hitspot.shoot == 1:

	if raySensor.isPositive():
		position = raySensor.getHitPosition()
		hitspot.setPosition(position)
		normal = raySensor.getHitNormal()
		up = [0, 0, 1]
		orientation = vecToMat3(normal, up)
		hitspot.setOrientation(orientation)
		hitObject = raySensor.getHitObject()

		if hasattr(hitObject, "is_dynamic"):
			rayVector = raySensor.getRayDirection()
			force = mul(hitspot.k_gunForce, rayVector)
			hitObject.applyImpulse(position, force)

		else:
			GameLogic.addActiveActuator(addMark, 1)

		if hasattr(hitObject, "hits"):
			hitObject.hits = hitObject.hits + hitspot.k_gunDamage

		GameLogic.addActiveActuator(addFlash, 1)

	hitspot.shoot = 0