TheGameCreators - CodeBase - Easy Collision and Jumping Engine

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Category: Collision

Version: 1.0

Information

Uploaded: 16th May 2005 15:16

Modified: 22nd May 2007 08:35

Author: Freddy 007

Summary

Simply a little easy-to-understand code snippet, on how to make basic collision.

Full Description

Simply a little easy-to-understand code snippet, on how to make basic collision. The code is written into sub-routines, so that you can easily pick the part of the code you want.<br /> Further description in the source code.

DarkBASIC Professional Source Code

` This code was downloaded from The Game Creators

` It is reproduced here with full permission

` http://www.thegamecreators.com

remstart

Author :

Frederik Lundgaard Hansen

A.K.A. Freddy007

Special thanks to Aura. Couldn't have made this without your help ;)

A short description of the program :

This program allows an object to jump around on a matrix. There will be some obstacles

that the object will be able to land on, and jump from one object to another.

It's basicly a simple collision snippet, but it's only meant for collisions from above,

when the player lands on the object.

Also, this code contains an easy jump-code, and in general the code SHOULD be easy to

understand, as I've remmed the most spectacular parts of the code. Besides, I've diveded,

well, actually the hole program into sub-routines, so you can pick out any part of the code

that you'll like to use.

I hope that someone will be able to use this code, either for jumping or the collision.

Thank you.

remend

gosub settings

gosub make_matrix

gosub make_player

gosub make_obstacles

gosub gravity_settings

gosub additional_settings_and_variables

gosub the_main_loop

settings:

`set the screen display mode to 1024x768, and set sync on, and the sync rate to 66:

set display mode 1024,768,32

sync on

sync rate 60

return

make_matrix:

make matrix 1,200,200,10,10

position matrix 1,-50,-2.5,-50

return

make_player:

make object cube 1,5

color object 1,RGB(15,139,1)

return

make_obstacles:

`make the obstacles, and position them on the ground:

make object box 2,20,10,20

position object 2,80,(object size y(2)/2),30

make object box 3,20,10,20

position object 3,100,(object size y(3)/2),0

make object box 4,20,10,20

position object 4,20,(object size y(4)/2),50

load object "test.x",5

position object 5,100,-100,50

return

gravity_settings:

`set the gravity. the gravity will decide how fast the thrust will devrement while

`the player is in the air:

gravity#=0.3

`the thrust will be the amount of power stored in the player object.

`this will decide how high the object will jump:

thrust#=4.0

`set the jump variable to 0. this variable will tell the program if the object is jumping or not:

jump = 0

return

additional_settings_and_variables:

`this is the speed our player object will be moved forward with:

movespeed=2

`set the variables for the object numbers

obj1=1

Land1=2

Land2=5

`make an array to store the player object positions in

Dim ObjectPosition#(obj1,3)

return

the_main_loop:

SaveObjectPosition(1)

gosub camera_stuff

gosub control_player

MultiSlidingCollision(obj1,land1,land2)

gosub check_jumping

remstart

un-rem this if you have an object as a floor. it'll make sure that you keep the exact same height

all the time. it checks the distance to the floor, and if you're too close, it moves

you away:

distance#=intersect object(Land1,object position x(obj1),object position y(obj1),object position z(obj1),object position x(obj1),object position y(obj1)-1,object position z(obj1))

set cursor 10,20 : print distance#

if distance#=0

else

if distance# < 1

position object obj1,object position x(obj1),object position y(obj1)+1-distance#,object position z(obj1)

endif

remend

gosub gravity

gosub collision_routine

sync

loop

`MY SUB-ROUTINES :

control_player:

set cursor 0,0

print screen fps()

`simple player control:

if keystate(17)

move object 1,-movespeed

endif

if keystate(31)

move object 1,2

endif

if keystate(30)

yrotate object 1,object angle y(1)-2

endif

if keystate(32)

yrotate object 1,object angle y(1)+2

endif

`if spacekey, then start the jumping process:

if keystate(57)

jump = 1

endif

return

camera_stuff:

set camera to follow object position x(1),object position y(1),object position z(1),object angle y(1),-30,20,10,0

return

collision_routine:

set object radius 1,6

`check for collisions on all the obstacles, and the player object:

for object= 2 to 5`change this if you've made new obstacles

`if any of the objects are colliding with the player:

if object collision(1,object) and object position y(1)>(object position y(object)+object size y(object)/2) and object exist(object)

`and the spacekey is NOT pressed, then set the thrust to zero, and the object will fall with the amount of zero:

if keystate(57)=0

print "collision"

thrust#=0

`if spacekey IS pressed, then set the thrust to 4, and let the jump-routine handle the rest:

else

thrust#=4

endif

`and then repeat the process for the next object:

next object

set object radius 1,2

return

gravity:

`check if the player is jumping(or if the player is not standing on the ground):

if object position y(1)>get ground height(1,object position x(1),object position y(1))

`if the object is in the air, then decrease the thrust with the gravity, and the object will fall down:

thrust#=thrust#-gravity#

`if the object is not in the air, then reset the thrust, and tell that the object is not in the air(jump=0)

else

thrust#=4.0

jump = 0

endif

return

check_jumping:

`if jump is positive, then move the player up with the amount of thrust.

`the object will then fall down, as the thrust gets decreased to a negative value

`by the gravity:

if jump = 1

move object up 1,thrust#

endif

`if jump is negative, then position the player on the ground:

if jump = 0

position object 1,object position x(1),get ground height(1,object position x(1),object position y(1)),object position z(1)

endif

return

function MultiSlidingCollision(obj,LandStart,LandEnd)

`store the player objects position for use later on:

X# = object position x(obj)

Y# = object position y(obj)

Z# = object position z(obj)

`position the object in the stored positions

position object obj,ObjectPosition#(obj,1),ObjectPosition#(obj,2),ObjectPosition#(obj,3)

`check for a collision between the player and the obstacles on the X-axis,

`and if a collision is detected, reset the players position:

position object obj,X#,object position y(obj),object position z(obj)

for land = LandStart to LandEnd

if land <> obj

if object exist(land)

if object collision(land,obj)

position object obj,ObjectPosition#(obj,1),object position y(obj),object position z(obj)

endif

next land

`and the same thing for the Z-axis:

position object obj,object position x(obj),object position y(obj),Z#

for land = LandStart to LandEnd

if land <> obj

if object exist(land)

if object collision(land,obj)

position object obj,object position x(obj),object position y(obj),ObjectPosition#(obj,3)

endif

next land

`and the Y-axis

position object obj,object position x(obj),Y#,object position z(obj)

for land = LandStart to LandEnd

if land <> obj

if object exist(land)

if object collision(land,obj)

position object obj,object position x(obj),ObjectPosition#(obj,2),object position z(obj)

endif

next land

endfunction

Function SaveObjectPosition(objnum)

`this will save the players position for later use:

ObjectPosition#(objnum,1) = object position x(objnum)

ObjectPosition#(objnum,2) = object position y(objnum)

ObjectPosition#(objnum,3) = object position z(objnum)

Endfunction

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Author Name:	Freddy 007
CodeBase Entries:	3

CodeBase - Easy Collision and Jumping Engine

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