Empowerment: Sliding Ninjas - The Game Maker's Companion: Game Development - page 95

Figure 4-19. The actions for the End Step event of the ice Zool state object

29. Add a Collision event with obj_slope and include a Set Variable action to set the
Variable y Relative to -speed*2 .
30. Include a Move to Contact action ( move tab) that sets Direction to 270 , Maximum to
-1 , and Against to all objects . This will bring Zool back down in contact with the slope.
31. Add a Key Press, Space event and include a Speed Vertical action that sets Vert. Speed
to

-22

. Jumping is the player's only way of controlling the slide .
32. Include a Change Instance action ( main1 tab) that will change into obj_zool_air and
Perform Events ( Destroy and Create ) as it does so.
If you spend a little time on the slopes now, you should see that we've already nearly got this
cracked. There is just one bug: if you jump back up the slope and manage to slide up to the top
and back onto a non-slippery platform, then you will get stuck. This is because we have not
handled collisions with other kinds of solid objects. We would really like this to have the same
sliding behavior as the obj_zool_air object because it would look quite strange to suddenly come
to a halt at the bottom of a slope. Therefore, we will copy the actions of that event and use it for
this one.