push object away from explosion center

Blitz3D Forums/Blitz3D Programming/push object away from explosion center

ryan scott

(Posted 2005) [#1]

i'm not sure how to make this happen... if an enemy_type explodes, i want every enemy within a certain radius to move away from the explosion a specific amount, say '10' for the sake of argument. i can't get my head around the math. this is a 2d on 3d game, by the way.

i have

if e\myexplode_pushesothers

for ee.enemy_type = each enemy_type
if dist2d(entityx(ee\piv,1),entityz(ee\piv,1),entityx(e\piv,1),entityz(e\piv,1)) < 5

move ee\piv 5 away from e\piv without turning him

endif
next
endif

it's that middle part i'm not sure on - do i maybe make a new pivot at the enemy to move, point it towards the explosion, turn it 180 degrees the other way, and translate to it, then remove the pivot? this seems to make sense. how do i do the translate to a spot?

ow my head hurts.

John Pickford

(Posted 2005) [#2]


   push_distance#=10
   explosion_radius#=100

   dx#=enemy_x - explosion_x
   dy#=enemy_y - explosion_y

   distance#=sqr(dx*dx+dy*dy)

if distance<explosion_radius

;normalize (create vector length 1)

  dx=dx/distance
  dy=dy/distance

  enemy_x=enemy_x+(dx*push_distance)
  enemy_y=enemy_y+(dy*push_distance)

endif