collision.py

from __future__ import division

from functions import place_free, sign, point_direction
import pygame
import math

def objectCheckCollision(character): pass
def characterHitObstacle(character, frametime): pass











"""
def objectCheckCollision(character):
	# Check if a the Character has hit the wall:
	hasCollided = False

	character.rect.centerx = character.x-character.xRectOffset
	character.rect.centery = character.y-character.yRectOffset

	clip = character.rect.clip(character.root.map.rect)

	# find where clip's top-left point is in both rectangles
	x1 = clip.left - character.root.map.rect.left
	y1 = clip.top  - character.root.map.rect.top
 
	# cycle through clip's area of the hitmasks
	for x in range(clip.width):
		for y in range(clip.height):
			# returns True if neither pixel is blank
			if character.root.map.mask.get_at((x1+x, y1+y)) == 1:
				hasCollided = True

	return hasCollided



def characterHitObstacle(character, frametime):


# THIS IS THE NEW VERSION; STILL WITH x/y


	newX = character.x
	newY = character.y

	hspeed = character.hspeed
	vspeed = character.vspeed

	length = math.hypot(hspeed, vspeed)

	if length == 0:# You haven't moved; if this happens something went wrong
		print "You haven't moved, yet managed to collide with something."
		return False


	# hs and vs is the normalized vector of hspeed and vspeed.
	hs = character.hspeed/length
	vs = character.vspeed/length

	while True:
		if not objectCheckCollision(character):
			break

		character.x -= hs * frametime
		character.y -= vs * frametime
   
	if hspeed == 0 or vspeed == 0:
		return True

	# This is the left-over velocity.
	hs = hspeed
	vs = vspeed

	# The character got pushed out, but now we need to let him move in the directions he's allowed to move.


	character.x += sign(hs)  * frametime

	if not objectCheckCollision(character) and abs(hs) > 0:

		# There's still room to move on the left/right

		i = 1
		while i <= abs(hs) and not objectCheckCollision(character):

			character.x += sign(hs)  * frametime
			i += 1


		if objectCheckCollision(character):
			character.x -= sign(hs)  * frametime

		return True

	else:

		# Stop horizontal movement
		character.hspeed = 0
		character.hs = 0
		character.x -= sign(hs)  * frametime


	character.y += sign(vs)  * frametime

	if not objectCheckCollision(character) and abs(vs) > 0:

		# There's still room to move on the left/right


		i = 1
		while i <= abs(vs) and not objectCheckCollision(character):

			character.y += sign(vs)  * frametime
			i += 1

		if objectCheckCollision(character):
			character.y -= sign(vs)  * frametime

		return True

	else:

		# INSERT STAIR CODE; SEE BELOW

		# Stop vertical movement
		character.vspeed = 0
		character.vs = 0
		character.y -= sign(vs)  * frametime

	return True









# STAIRS CODE; INSERT IN "STAIR CODE" ONCE FIXED
'''

		character.y -= 6

		if not objectCheckCollision(character):

			character.y += 6# This is to compensate for the loop.
			character.x -= sign(character.hspeed)*6

			while hs*sign(character.hspeed) > 0:

				character.y -= 6
				character.x += sign(character.hspeed)*6
				hs -= sign(character.hspeed)*6

				if objectCheckCollision(character):

					character.y += 6
					character.x -= sign(character.hspeed)*6
					break

		else:'''





"""











'''



# THIS IS THE ORIGNAL GG2 COLLISION CODE, PORTED FRESH FROM GMK. Not needed.

	# The Character has collided; Push him back out:

	# This code was written for a situation before the character actually moved, but I want to keep this compatible with our structure.
	# Hence; move everything back, and move forward as far as we can.

	character.x -= character.hspeed
	character.y -= character.vspeed

	hleft = character.hspeed
	vleft = character.vspeed

	loopCounter = 0
	stuck = 0
	collisionRectified = True
	while((abs(hleft) >= 1 or abs(vleft) >= 1) and stuck == 0): # while we still have distance to travel
		loopCounter += 1
		if(loopCounter > 10):
			# After 10 loops, it's assumed we're stuck. Stop all vertical movement.
			stuck = 1

		collisionRectified = False # set this to true when we fix a collision problem
		# (eg. detect hitting the ceiling and setting vspeed = 0)
		# if, after checking for all our possible collisions, we realize that we haven't
		# been able to fix a collision problem, then we probably hit a corner or something,
		# and we should try to fix that

		prevX = character.x
		prevY = character.y


		# move as far as we can without hitting something
		# In GMK, this was "move_contact_solid(point_direction(x, y, x + hleft, y + vleft), point_distance(x, y, x + hleft, y + vleft))"

		length = functions.lengthdir(hleft, vleft)
		distance = 0

		while distance < length:

			character.x = character.x+hleft*distance
			character.y = character.y+vleft*distance

			if objectCheckCollision(character, wallmask):
				character.x = character.x-hleft*distance
				character.y = character.y-vleft*distance
				break

			distance += length/20


		# deduct that movement from our remaining movement
		hleft -= (character.x - prevX)
		vleft -= (character.y - prevY)

		# determine what we hit, and act accordingly

		if(vleft != 0 and not functions.place_free(character.x, character.y + functions.sign(vleft), wallmask)):  # we hit a ceiling or floor
			if(vleft>0):
				moveStatus = 0 # floors, not ceilings, reset moveStatus
		
			vleft = 0 # don't go up or down anymore
			character.vspeed = 0 # don't try it next frame, either
			collisionRectified = True
	

		if(hleft != 0 and not functions.place_free(character.x + functions.sign(hleft), character.y, wallmask)):  # we hit a wall on the left or right
			moveStatus = 0
			if(functions.place_free(character.x + functions.sign(hleft), character.y - 6, wallmask)):  # if we could just walk up the step
				character.y -= 6 # hop up the step.
			collisionRectified = True
	
#		elif(functions.place_free(character.x + functions.sign(hleft), character.y + 6, wallmask) and abs(character.hspeed) >= abs(character.vspeed)): # ceiling sloping
#	
#			character.y += 6
#			collisionRectified = True
	
		else: # it's not just a step, we've actually gotta stop
	
			hleft = 0 # don't go left or right anymore
			characterhspeed = 0 # don't try it next frame, either
			collisionRectified = True
	

	if(not collisionRectified and (abs(hleft) >= 1 or abs(vleft) >= 1)):
		# uh-oh, no collisions fixed, try stopping all vertical movement and see what happens
		charactervspeed = 0
		vleft = 0'''