Why won't this collision testing code work? (No sparkys)

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CocaCola

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Location: CocaCola.x CocaCola.y CocaCola.z

Posted: 5th Aug 2010 04:32

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Yeah I have sparkys collision but I didn't use it, I've used this way of collision before and it works perfect (Thanks Hawkblood

) but when my player starts he just does a wierd thing then keeps falling.
This code should work with anyone (I didn't use any media)

sync on
sync rate 60
autocam off
make camera 1
make object cube 1,5
position object 1,0,6,0
make object cube 2,5
position object 2,0,5,5
make object cube 3,5
position object 3,0,10,10
make object cube 4,5
position object 4,0,15,15
make object cube 5,5
position object 5,0,0,0
do
	move object down 1,falling#
	inc falling#,0.1
	x=object position x(1)
	x=object position y(1)
	x=object position z(1)
		for b=2 to 5
		D#=INTERSECT OBJECT(b,x+10,y,z,x+10,y-10.0,z) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
		D#=INTERSECT OBJECT(b,x-10,y,z,x-10,y-10.0,z) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
		D#=INTERSECT OBJECT(b,x,y,z+10,x,y-10.0,z+10) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
		D#=INTERSECT OBJECT(b,x,y,z-10,x,y-10.0,z-10) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
	Next b
	position camera 1,object position x(1),object position y(1),object position z(1)-15
	x=object position x(1)
	y=object position y(1)
	z=object position z(1)
	if upkey()=1 then position object 1,x,y,z+1
	if downkey()=1 then position object 1,x,y,z-1
	if rightkey()=1 then position object 1,x+1,y,z
	if leftkey()=1 then position object 1,x-1,y,z
	if spacekey()=1 and Falling#=0.0
		move object up 1,1
		Falling#=-3.0
	endif
	x2=object position x(1)
	y2=object position y(1)
	z2=object position z(1)
		for b=2 to 5
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2-10.0,y2,z2)
		if D#<10.0 and D#>0.0
			position object 1,x2+(10.0-D#),y2,z2
		Endif
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2+10.0,y2,z2)
		if D#<10.0 and D#>0.0
			position object 1,x2-(10.0-D#),y2,z2
		Endif
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2,y2,z2-10.0)
		if D#<10.0 and D#>0.0
			position object 1,x2,y2,z2+(10.0-D#)
		Endif
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2,y2,z2+10.0)
		if D#<10.0 and D#>0.0
			position object 1,x2,y2,z2-(10.0-D#)
		Endif
	Next b
	sync
	loop

+ Code Snippet

sync on
sync rate 60
autocam off
make camera 1
make object cube 1,5
position object 1,0,6,0
make object cube 2,5
position object 2,0,5,5
make object cube 3,5
position object 3,0,10,10
make object cube 4,5
position object 4,0,15,15
make object cube 5,5
position object 5,0,0,0
do
	move object down 1,falling#
	inc falling#,0.1
	x=object position x(1)
	x=object position y(1)
	x=object position z(1)
		for b=2 to 5
		D#=INTERSECT OBJECT(b,x+10,y,z,x+10,y-10.0,z) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
		D#=INTERSECT OBJECT(b,x-10,y,z,x-10,y-10.0,z) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
		D#=INTERSECT OBJECT(b,x,y,z+10,x,y-10.0,z+10) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
		D#=INTERSECT OBJECT(b,x,y,z-10,x,y-10.0,z-10) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
	Next b
	position camera 1,object position x(1),object position y(1),object position z(1)-15
	x=object position x(1)
	y=object position y(1)
	z=object position z(1)
	if upkey()=1 then position object 1,x,y,z+1
	if downkey()=1 then position object 1,x,y,z-1
	if rightkey()=1 then position object 1,x+1,y,z
	if leftkey()=1 then position object 1,x-1,y,z
	if spacekey()=1 and Falling#=0.0
		move object up 1,1
		Falling#=-3.0
	endif
	x2=object position x(1)
	y2=object position y(1)
	z2=object position z(1)
		for b=2 to 5
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2-10.0,y2,z2)
		if D#<10.0 and D#>0.0
			position object 1,x2+(10.0-D#),y2,z2
		Endif
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2+10.0,y2,z2)
		if D#<10.0 and D#>0.0
			position object 1,x2-(10.0-D#),y2,z2
		Endif
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2,y2,z2-10.0)
		if D#<10.0 and D#>0.0
			position object 1,x2,y2,z2+(10.0-D#)
		Endif
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2,y2,z2+10.0)
		if D#<10.0 and D#>0.0
			position object 1,x2,y2,z2-(10.0-D#)
		Endif
	Next b
	sync
	loop

Darkbasic Pro 7.4-7.5
Windows Vista

I want coke, not Pepsi!

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Kira Vakaan

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Joined: 1st Dec 2008

Location: MI, United States

Posted: 5th Aug 2010 09:50

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I'm sure you didn't mean to do this:

+ Code Snippet

x=object position x(1)
x=object position y(1)
x=object position z(1)

Not sure why you're not using Sparky's for this... If not for the amazing sliding collision, for the raycasting. Sparky's raycasting is much better than DBPro's.

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TheComet

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Posted: 5th Aug 2010 19:03

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And it's much faster too. It would be very easy to implement into your current code, since the intersect command in sparky's is almost no different.

TheComet

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CocaCola

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Location: CocaCola.x CocaCola.y CocaCola.z

Posted: 5th Aug 2010 20:04 Edited at: 5th Aug 2010 20:27

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ohh!!! Kira thanks I'll edit that now, I was copying and pasting from my other code because this is a test code.
Ok, I didn't want to edit all of my code so I used my old one, there pretty much the same, but test it and you'll see that when you go to the top and try to go left or right it has the collision of a box and I know that thats because of the intersect objects (This is also my code).

sync on
sync rate 80
set global collision on
backdrop on
autocam off
make object box 1,5,20,5
position object 1,0,20,0
color object 1,RGB(255,255,60)
make object cube 2,20
position object 2,0,0,0
make object cube 3,20
position object 3,20,0,0
make object cube 4,20
position object 4,40,0,0
make object cube 5,20
position object 5,60,0,0
make object cube 6,20
position object 6,60,20,0
make object cube 7,20
position object 7,80,40,0
make object cube 8,20
position object 8,80,60,20
make object cube 9,20
position object 9,80,60,-20
make camera 1
Do
	move object down 1,Falling#
	inc Falling#,0.1
	x=object position x(1)
	y=object position y(1)
	z=object position z(1)
	for b=2 to 9
		D#=INTERSECT OBJECT(b,x+10,y,z,x+10,y-10.0,z) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
		D#=INTERSECT OBJECT(b,x-10,y,z,x-10,y-10.0,z) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
		D#=INTERSECT OBJECT(b,x,y,z+10,x,y-10.0,z+10) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
		D#=INTERSECT OBJECT(b,x,y,z-10,x,y-10.0,z-10) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
	Next b
	position camera 1,OBJECT POSITION X(1)-15,OBJECT POSITION Y(1),OBJECT POSITION Z(1)
	yrotate camera 1,90
	x=object position x(1)
	y=object position y(1)
	z=object position z(1)
	if upkey()=1 then position object 1,x+1,y,z
	if downkey()=1 then position object 1,x-1,y,z
	if rightkey()=1 then position object 1,x,y,z-1
	if leftkey()=1 then position object 1,x,y,z+1
	if spacekey()=1 and Falling#=0.0
		move object up 1,1
		Falling#=-3.0
	endif
	x2=object position x(1)
	y2=object position y(1)
	z2=object position z(1)
REM *** THIS IS FOR THE SIDE-TO-SIDE CHECKS ****
	for b=2 to 9
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2-10.0,y2,z2)
		if D#<10.0 and D#>0.0
			position object 1,x2+(10.0-D#),y2,z2
		Endif
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2+10.0,y2,z2)
		if D#<10.0 and D#>0.0
			position object 1,x2-(10.0-D#),y2,z2
		Endif
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2,y2,z2-10.0)
		if D#<10.0 and D#>0.0
			position object 1,x2,y2,z2+(10.0-D#)
		Endif
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2,y2,z2+10.0)
		if D#<10.0 and D#>0.0
			position object 1,x2,y2,z2-(10.0-D#)
		Endif
	Next b
	sync
loop

+ Code Snippet

sync on
sync rate 80
set global collision on
backdrop on
autocam off
make object box 1,5,20,5
position object 1,0,20,0
color object 1,RGB(255,255,60)
make object cube 2,20
position object 2,0,0,0
make object cube 3,20
position object 3,20,0,0
make object cube 4,20
position object 4,40,0,0
make object cube 5,20
position object 5,60,0,0
make object cube 6,20
position object 6,60,20,0
make object cube 7,20
position object 7,80,40,0
make object cube 8,20
position object 8,80,60,20
make object cube 9,20
position object 9,80,60,-20
make camera 1
Do
	move object down 1,Falling#
	inc Falling#,0.1
	x=object position x(1)
	y=object position y(1)
	z=object position z(1)
	for b=2 to 9
		D#=INTERSECT OBJECT(b,x+10,y,z,x+10,y-10.0,z) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
		D#=INTERSECT OBJECT(b,x-10,y,z,x-10,y-10.0,z) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
		D#=INTERSECT OBJECT(b,x,y,z+10,x,y-10.0,z+10) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
		D#=INTERSECT OBJECT(b,x,y,z-10,x,y-10.0,z-10) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
	Next b
	position camera 1,OBJECT POSITION X(1)-15,OBJECT POSITION Y(1),OBJECT POSITION Z(1)
	yrotate camera 1,90
	x=object position x(1)
	y=object position y(1)
	z=object position z(1)
	if upkey()=1 then position object 1,x+1,y,z
	if downkey()=1 then position object 1,x-1,y,z
	if rightkey()=1 then position object 1,x,y,z-1
	if leftkey()=1 then position object 1,x,y,z+1
	if spacekey()=1 and Falling#=0.0
		move object up 1,1
		Falling#=-3.0
	endif
	x2=object position x(1)
	y2=object position y(1)
	z2=object position z(1)
REM *** THIS IS FOR THE SIDE-TO-SIDE CHECKS ****
	for b=2 to 9
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2-10.0,y2,z2)
		if D#<10.0 and D#>0.0
			position object 1,x2+(10.0-D#),y2,z2
		Endif
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2+10.0,y2,z2)
		if D#<10.0 and D#>0.0
			position object 1,x2-(10.0-D#),y2,z2
		Endif
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2,y2,z2-10.0)
		if D#<10.0 and D#>0.0
			position object 1,x2,y2,z2+(10.0-D#)
		Endif
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2,y2,z2+10.0)
		if D#<10.0 and D#>0.0
			position object 1,x2,y2,z2-(10.0-D#)
		Endif
	Next b
	sync
loop

Anyway with sparkys do you have to decide where your collisions are (or whatever) like in above or does it do something like view your object and then make collisions (so it's more precise)? If so how would I do that?

For example in my code above making collisions for a box

is easy but if you wanted something like a circle

I don't think it would be very precise.

I want coke, not Pepsi!

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Kira Vakaan

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Joined: 1st Dec 2008

Location: MI, United States

Posted: 5th Aug 2010 21:18

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I'm not sure what you're asking about Sparky's, but here's an example I threw together for sliding collision using Sparky's.

set display mode 1024,768,32,1
sync on

autocam off
hide mouse

`Player
Player=1
PlayerRadius#=2
make object sphere Player,2*PlayerRadius#
position object Player,0,10,0
Gravity#=0.1
XVel#=0.0
YVel#=0.0
ZVel#=0.0
Speed#=0.4
MaxSlope#=0.75

`Ground and stuff
TerrainGroup=1
make object box 2,100,2,100
position object 2,0,-1,0
SC_setupObject 2,TerrainGroup,2
for a=3 to 13
  make object cube a,rnd(5)+2
  position object a,rnd(90)-45,object size y(a)/2.0,rnd(90)-45
  yrotate object a,rnd(360)
  SC_setupObject a,TerrainGroup,2
next a

do
  XPos#=object position x(Player)
  YPos#=object position y(Player)
  ZPos#=object position z(Player)

`Mouse Look
  xrotate object Player,wrapvalue(object angle x(Player)+mousemovey()/5.0)
  yrotate object Player,wrapvalue(object angle y(Player)+mousemovex()/5.0)
  
  XVel#=0.0
  ZVel#=0.0
  
  `W
  if keystate(17) then inc XVel#,Speed#*sin(object angle y(Player)) : inc ZVel#,Speed#*cos(object angle y(Player))
  `S
  if keystate(31) then dec XVel#,Speed#*sin(object angle y(Player)) : dec ZVel#,Speed#*cos(object angle y(Player))
  `A
  if keystate(30) then inc XVel#,Speed#*sin(object angle y(Player)-90) : inc ZVel#,Speed#*cos(object angle y(Player)-90)
  `D
  if keystate(32) then inc XVel#,Speed#*sin(object angle y(Player)+90) : inc ZVel#,Speed#*cos(object angle y(Player)+90)
  
  dec YVel#,Gravity#
  
  `Test for slope
  Collision=SC_sphereCastGroup(TerrainGroup,XPos#,YPos#,ZPos#,XPos#,YPos#+YVel#,ZPos#,PlayerRadius#,0)
  if Collision
    if abs(SC_getCollisionNormalY())>MaxSlope#
      `We are not on a slope.  Stick to the ground.
      YPos#=SC_getStaticCollisionY()
      YVel#=0
    else
      `We are on a slope.  Slide down it.
      XPos#=SC_getCollisionSlideX()
      YPos#=SC_getCollisionSlideY()
      ZPos#=SC_getCollisionSlideZ()
    endif
  else
    `No collision.  Let the player fall.
    inc YPos#,YVel#
  endif
  
  `Test for walls
  Collision=SC_sphereSlideGroup(TerrainGroup,XPos#,YPos#,ZPos#,XPos#+XVel#,YPos#,ZPos#+ZVel#,PlayerRadius#,0)
  if Collision
    `We hit something.  Slide along the surface.
    XPos#=SC_getCollisionSlideX()
    YPos#=SC_getCollisionSlideY()
    ZPos#=SC_getCollisionSlideZ()
  else
    `No collision.  Move the player normally.
    inc XPos#,XVel#
    inc ZPos#,ZVel#
  endif
  
  position object Player,XPos#,YPos#,ZPos#
  position camera 0,object position x(Player),object position y(Player),object position z(Player)
  rotate camera 0,object angle x(Player),object angle y(Player),0
  
  sync
loop

+ Code Snippet

set display mode 1024,768,32,1
sync on

autocam off
hide mouse

`Player
Player=1
PlayerRadius#=2
make object sphere Player,2*PlayerRadius#
position object Player,0,10,0
Gravity#=0.1
XVel#=0.0
YVel#=0.0
ZVel#=0.0
Speed#=0.4
MaxSlope#=0.75

`Ground and stuff
TerrainGroup=1
make object box 2,100,2,100
position object 2,0,-1,0
SC_setupObject 2,TerrainGroup,2
for a=3 to 13
  make object cube a,rnd(5)+2
  position object a,rnd(90)-45,object size y(a)/2.0,rnd(90)-45
  yrotate object a,rnd(360)
  SC_setupObject a,TerrainGroup,2
next a

do
  XPos#=object position x(Player)
  YPos#=object position y(Player)
  ZPos#=object position z(Player)

  `Mouse Look
  xrotate object Player,wrapvalue(object angle x(Player)+mousemovey()/5.0)
  yrotate object Player,wrapvalue(object angle y(Player)+mousemovex()/5.0)
  
  XVel#=0.0
  ZVel#=0.0
  
  `W
  if keystate(17) then inc XVel#,Speed#*sin(object angle y(Player)) : inc ZVel#,Speed#*cos(object angle y(Player))
  `S
  if keystate(31) then dec XVel#,Speed#*sin(object angle y(Player)) : dec ZVel#,Speed#*cos(object angle y(Player))
  `A
  if keystate(30) then inc XVel#,Speed#*sin(object angle y(Player)-90) : inc ZVel#,Speed#*cos(object angle y(Player)-90)
  `D
  if keystate(32) then inc XVel#,Speed#*sin(object angle y(Player)+90) : inc ZVel#,Speed#*cos(object angle y(Player)+90)
  
  dec YVel#,Gravity#
  
  `Test for slope
  Collision=SC_sphereCastGroup(TerrainGroup,XPos#,YPos#,ZPos#,XPos#,YPos#+YVel#,ZPos#,PlayerRadius#,0)
  if Collision
    if abs(SC_getCollisionNormalY())>MaxSlope#
      `We are not on a slope.  Stick to the ground.
      YPos#=SC_getStaticCollisionY()
      YVel#=0
    else
      `We are on a slope.  Slide down it.
      XPos#=SC_getCollisionSlideX()
      YPos#=SC_getCollisionSlideY()
      ZPos#=SC_getCollisionSlideZ()
    endif
  else
    `No collision.  Let the player fall.
    inc YPos#,YVel#
  endif
  
  `Test for walls
  Collision=SC_sphereSlideGroup(TerrainGroup,XPos#,YPos#,ZPos#,XPos#+XVel#,YPos#,ZPos#+ZVel#,PlayerRadius#,0)
  if Collision
    `We hit something.  Slide along the surface.
    XPos#=SC_getCollisionSlideX()
    YPos#=SC_getCollisionSlideY()
    ZPos#=SC_getCollisionSlideZ()
  else
    `No collision.  Move the player normally.
    inc XPos#,XVel#
    inc ZPos#,ZVel#
  endif
  
  position object Player,XPos#,YPos#,ZPos#
  position camera 0,object position x(Player),object position y(Player),object position z(Player)
  rotate camera 0,object angle x(Player),object angle y(Player),0
  
  sync
loop

Test it out, study the code, read the help files for commands you don't understand. If you've done all that and still don't know what's going on, we'll be happy to help.

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CocaCola

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Posted: 5th Aug 2010 22:15 Edited at: 6th Aug 2010 01:39

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I will try to understand it, and what I mean't was in my code above it has box collision

so if the player wasn't a box and but a circle

the circle would still have the box collision, can sparkys do precise collision so even if you had something like this

it would have precise collision?
EDIT: I just tested that code of yours, it seems to do the exact same thing as mine

I want coke, not Pepsi!

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Kira Vakaan

17

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Joined: 1st Dec 2008

Location: MI, United States

Posted: 6th Aug 2010 02:44

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First yours casts axis-aligned rays from each corner of a cube downward, and then casts rays from the center of the cube through the center of each of the four sides for collisions. That leaves a lot of room for collisions to go undetected. Here, I've setup a little scene using your code to highlight the problems. I've placed the player very high up so he'll fall at the beginning. There's a "spike" underneath him that will go undetected, and then there's a crack in the wall ahead that he can walk through. When you run the code, just let the character fall to the ground and after he lands, walk straight forward.

Here it is:

sync on
sync rate 80
set global collision on
backdrop on
autocam off
make object box 1,5,20,5
position object 1,0,100,0
color object 1,RGB(255,255,60)
make object box 2,100,2,100
position object 2,0,-1,0
make object cube 3,20
position object 3,30,10,2
make object cube 4,20
position object 4,30,10,-20
make object box 5,2,20,2
position object 5,1.5,10,1.5
make camera 1
Do
  set cursor 0,0
  print object position z(1)
	move object down 1,Falling#
	inc Falling#,0.1
	x=object position x(1)
	y=object position y(1)
	z=object position z(1)
	for b=2 to 5
		D#=INTERSECT OBJECT(b,x+10,y,z,x+10,y-10.0,z) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
		D#=INTERSECT OBJECT(b,x-10,y,z,x-10,y-10.0,z) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
		D#=INTERSECT OBJECT(b,x,y,z+10,x,y-10.0,z+10) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
		D#=INTERSECT OBJECT(b,x,y,z-10,x,y-10.0,z-10) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
	Next b
	x=object position x(1)
	y=object position y(1)
	z=object position z(1)
	if upkey()=1 then position object 1,x+1,y,z
	if downkey()=1 then position object 1,x-1,y,z
	if rightkey()=1 then position object 1,x,y,z-1
	if leftkey()=1 then position object 1,x,y,z+1
	if spacekey()=1 and Falling#=0.0
		move object up 1,1
		Falling#=-3.0
	endif
	x2=object position x(1)
	y2=object position y(1)
	z2=object position z(1)
REM *** THIS IS FOR THE SIDE-TO-SIDE CHECKS ****
	for b=2 to 5
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2-10.0,y2,z2)
		if D#<10.0 and D#>0.0
			position object 1,x2+(10.0-D#),y2,z2
		Endif
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2+10.0,y2,z2)
		if D#<10.0 and D#>0.0
			position object 1,x2-(10.0-D#),y2,z2
		Endif
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2,y2,z2-10.0)
		if D#<10.0 and D#>0.0
			position object 1,x2,y2,z2+(10.0-D#)
		Endif
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2,y2,z2+10.0)
		if D#<10.0 and D#>0.0
			position object 1,x2,y2,z2-(10.0-D#)
		Endif
	Next b
	position camera 1,OBJECT POSITION X(1)-35,OBJECT POSITION Y(1)+50,OBJECT POSITION Z(1)
	point camera 1,object position x(1),object position y(1),object position z(1)
	
	sync
loop

+ Code Snippet

sync on
sync rate 80
set global collision on
backdrop on
autocam off
make object box 1,5,20,5
position object 1,0,100,0
color object 1,RGB(255,255,60)
make object box 2,100,2,100
position object 2,0,-1,0
make object cube 3,20
position object 3,30,10,2
make object cube 4,20
position object 4,30,10,-20
make object box 5,2,20,2
position object 5,1.5,10,1.5
make camera 1
Do
  set cursor 0,0
  print object position z(1)
	move object down 1,Falling#
	inc Falling#,0.1
	x=object position x(1)
	y=object position y(1)
	z=object position z(1)
	for b=2 to 5
		D#=INTERSECT OBJECT(b,x+10,y,z,x+10,y-10.0,z) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
		D#=INTERSECT OBJECT(b,x-10,y,z,x-10,y-10.0,z) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
		D#=INTERSECT OBJECT(b,x,y,z+10,x,y-10.0,z+10) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
		D#=INTERSECT OBJECT(b,x,y,z-10,x,y-10.0,z-10) `this tests the "Ground Mesh" for a collision (or ray intersection)
		if D#<10.0 and D#>0.0
			position object 1,x,y+(10.0-D#),z
			Falling#=0
		Endif
	Next b
	x=object position x(1)
	y=object position y(1)
	z=object position z(1)
	if upkey()=1 then position object 1,x+1,y,z
	if downkey()=1 then position object 1,x-1,y,z
	if rightkey()=1 then position object 1,x,y,z-1
	if leftkey()=1 then position object 1,x,y,z+1
	if spacekey()=1 and Falling#=0.0
		move object up 1,1
		Falling#=-3.0
	endif
	x2=object position x(1)
	y2=object position y(1)
	z2=object position z(1)
REM *** THIS IS FOR THE SIDE-TO-SIDE CHECKS ****
	for b=2 to 5
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2-10.0,y2,z2)
		if D#<10.0 and D#>0.0
			position object 1,x2+(10.0-D#),y2,z2
		Endif
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2+10.0,y2,z2)
		if D#<10.0 and D#>0.0
			position object 1,x2-(10.0-D#),y2,z2
		Endif
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2,y2,z2-10.0)
		if D#<10.0 and D#>0.0
			position object 1,x2,y2,z2+(10.0-D#)
		Endif
		D#=INTERSECT OBJECT(b,x2,y2,z2,x2,y2,z2+10.0)
		if D#<10.0 and D#>0.0
			position object 1,x2,y2,z2-(10.0-D#)
		Endif
	Next b
	position camera 1,OBJECT POSITION X(1)-35,OBJECT POSITION Y(1)+50,OBJECT POSITION Z(1)
	point camera 1,object position x(1),object position y(1),object position z(1)
	
	sync
loop

Oh, and I've simply moved the camera placing commands to fix that one-frame-long lag that happens whenever you move.

My code, on the other hand, casts a perfect sphere along the direction of travel, eliminating any of the same problems.

Change line 87 and 88 of my code to this:

+ Code Snippet

  rotate camera 0,80,object angle y(Player),0
  move camera 0,-25

to see how the code deals with corners and such.

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CocaCola

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Joined: 23rd Mar 2010

Location: CocaCola.x CocaCola.y CocaCola.z

Posted: 6th Aug 2010 03:11

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Can you recreate that scene using sparkys to show me what difference it makes?

I want coke, not Pepsi!

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Kira Vakaan

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Joined: 1st Dec 2008

Location: MI, United States

Posted: 6th Aug 2010 03:32

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Quote: "My code, on the other hand, casts a perfect sphere along the direction of travel, eliminating any of the same problems"

...is the difference it makes...

Here it is anyway...

set display mode 1024,768,32,1
sync on

autocam off
hide mouse

`Player
Player=1
PlayerRadius#=2.5
make object sphere Player,2*PlayerRadius#
position object Player,0,50,0
Gravity#=0.1
XVel#=0.0
YVel#=0.0
ZVel#=0.0
Speed#=0.4
MaxSlope#=0.75

`Ground and stuff
TerrainGroup=1
make object box 2,100,2,100
position object 2,0,-1,0
SC_setupObject 2,TerrainGroup,2
make object box 3,1,10,1
position object 3,-.75,5,.75
SC_setupObject 3,TerrainGroup,2
make object cube 4,10
position object 4,-6,5,25
SC_setupObject 4,TerrainGroup,2
make object cube 5,10
position object 5,6,5,25
SC_setupObject 5,TerrainGroup,2

do
  XPos#=object position x(Player)
  YPos#=object position y(Player)
  ZPos#=object position z(Player)

XVel#=0.0
  ZVel#=0.0
  
  `W
  if keystate(17) then inc XVel#,Speed#*sin(object angle y(Player)) : inc ZVel#,Speed#*cos(object angle y(Player))
  `S
  if keystate(31) then dec XVel#,Speed#*sin(object angle y(Player)) : dec ZVel#,Speed#*cos(object angle y(Player))
  `A
  if keystate(30) then inc XVel#,Speed#*sin(object angle y(Player)-90) : inc ZVel#,Speed#*cos(object angle y(Player)-90)
  `D
  if keystate(32) then inc XVel#,Speed#*sin(object angle y(Player)+90) : inc ZVel#,Speed#*cos(object angle y(Player)+90)
  
  dec YVel#,Gravity#
  
  `Test for slope
  Collision=SC_sphereCastGroup(TerrainGroup,XPos#,YPos#,ZPos#,XPos#,YPos#+YVel#,ZPos#,PlayerRadius#,0)
  if Collision
    if abs(SC_getCollisionNormalY())>MaxSlope#
      `We are not on a slope.  Stick to the ground.
      YPos#=SC_getStaticCollisionY()
      YVel#=0
    else
      `We are on a slope.  Slide down it.
      XPos#=SC_getCollisionSlideX()
      YPos#=SC_getCollisionSlideY()
      ZPos#=SC_getCollisionSlideZ()
    endif
  else
    `No collision.  Let the player fall.
    inc YPos#,YVel#
  endif
  
  `Test for walls
  Collision=SC_sphereSlideGroup(TerrainGroup,XPos#,YPos#,ZPos#,XPos#+XVel#,YPos#,ZPos#+ZVel#,PlayerRadius#,0)
  if Collision
    `We hit something.  Slide along the surface.
    XPos#=SC_getCollisionSlideX()
    YPos#=SC_getCollisionSlideY()
    ZPos#=SC_getCollisionSlideZ()
  else
    `No collision.  Move the player normally.
    inc XPos#,XVel#
    inc ZPos#,ZVel#
  endif
  
  position object Player,XPos#,YPos#,ZPos#
  position camera 0,object position x(Player),object position y(Player)+25,object position z(Player)-17.5
  point camera 0,object position x(Player),object position y(Player),object position z(Player)
  
  sync
loop

+ Code Snippet

set display mode 1024,768,32,1
sync on

autocam off
hide mouse

`Player
Player=1
PlayerRadius#=2.5
make object sphere Player,2*PlayerRadius#
position object Player,0,50,0
Gravity#=0.1
XVel#=0.0
YVel#=0.0
ZVel#=0.0
Speed#=0.4
MaxSlope#=0.75

`Ground and stuff
TerrainGroup=1
make object box 2,100,2,100
position object 2,0,-1,0
SC_setupObject 2,TerrainGroup,2
make object box 3,1,10,1
position object 3,-.75,5,.75
SC_setupObject 3,TerrainGroup,2
make object cube 4,10
position object 4,-6,5,25
SC_setupObject 4,TerrainGroup,2
make object cube 5,10
position object 5,6,5,25
SC_setupObject 5,TerrainGroup,2

do
  XPos#=object position x(Player)
  YPos#=object position y(Player)
  ZPos#=object position z(Player)

  XVel#=0.0
  ZVel#=0.0
  
  `W
  if keystate(17) then inc XVel#,Speed#*sin(object angle y(Player)) : inc ZVel#,Speed#*cos(object angle y(Player))
  `S
  if keystate(31) then dec XVel#,Speed#*sin(object angle y(Player)) : dec ZVel#,Speed#*cos(object angle y(Player))
  `A
  if keystate(30) then inc XVel#,Speed#*sin(object angle y(Player)-90) : inc ZVel#,Speed#*cos(object angle y(Player)-90)
  `D
  if keystate(32) then inc XVel#,Speed#*sin(object angle y(Player)+90) : inc ZVel#,Speed#*cos(object angle y(Player)+90)
  
  dec YVel#,Gravity#
  
  `Test for slope
  Collision=SC_sphereCastGroup(TerrainGroup,XPos#,YPos#,ZPos#,XPos#,YPos#+YVel#,ZPos#,PlayerRadius#,0)
  if Collision
    if abs(SC_getCollisionNormalY())>MaxSlope#
      `We are not on a slope.  Stick to the ground.
      YPos#=SC_getStaticCollisionY()
      YVel#=0
    else
      `We are on a slope.  Slide down it.
      XPos#=SC_getCollisionSlideX()
      YPos#=SC_getCollisionSlideY()
      ZPos#=SC_getCollisionSlideZ()
    endif
  else
    `No collision.  Let the player fall.
    inc YPos#,YVel#
  endif
  
  `Test for walls
  Collision=SC_sphereSlideGroup(TerrainGroup,XPos#,YPos#,ZPos#,XPos#+XVel#,YPos#,ZPos#+ZVel#,PlayerRadius#,0)
  if Collision
    `We hit something.  Slide along the surface.
    XPos#=SC_getCollisionSlideX()
    YPos#=SC_getCollisionSlideY()
    ZPos#=SC_getCollisionSlideZ()
  else
    `No collision.  Move the player normally.
    inc XPos#,XVel#
    inc ZPos#,ZVel#
  endif
  
  position object Player,XPos#,YPos#,ZPos#
  position camera 0,object position x(Player),object position y(Player)+25,object position z(Player)-17.5
  point camera 0,object position x(Player),object position y(Player),object position z(Player)
  
  sync
loop

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CocaCola

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Joined: 23rd Mar 2010

Location: CocaCola.x CocaCola.y CocaCola.z

Posted: 6th Aug 2010 04:27

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How would you add jumping to sparkys using that code?
I understood it with the other code, so it's gonna take me a bit to understand this one (hopefully not 70 posts like understanding the first collision...)

I want coke, not Pepsi!

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Kira Vakaan

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Joined: 1st Dec 2008

Location: MI, United States

Posted: 6th Aug 2010 04:34

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Have you looked? If you look in the movement section of the code, it would appear that the variables XVel#, YVel#, and ZVel# control the velocity of the player. That should be enough info to figure it out. Try some things first and everyone will be more willing to help you.

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CocaCola

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Posted: 6th Aug 2010 04:52 Edited at: 6th Aug 2010 05:54

Link

I tried this

+ Code Snippet

  if spacekey()=1 and YVel#=0 then position object 1,XPos#,YPos#+5,ZPos# and Gravity#=2.0

in hopes to if you press spacekey and the player is on the ground it will position object 1, 5 places above then activate the gravity. What is wrong with it?

I want coke, not Pepsi!

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CocaCola

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Posted: 6th Aug 2010 10:33 Edited at: 6th Aug 2010 10:35

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I don't understand most of this (pretty much the whole code but i'll point out the main parts, then we can work on the other stuff)

`Player
Player=1
PlayerRadius#=2.5
make object sphere Player,2*PlayerRadius#
position object Player,0,50,0
Gravity#=0.1
XVel#=0.0
YVel#=0.0
ZVel#=0.0
Speed#=0.4
MaxSlope#=0.75

`Ground and stuff
TerrainGroup=1
make object box 2,100,2,100
position object 2,0,-1,0
SC_setupObject 2,TerrainGroup,2
make object box 3,1,10,1
position object 3,-.75,5,.75
SC_setupObject 3,TerrainGroup,2
make object cube 4,10
position object 4,-6,5,25
SC_setupObject 4,TerrainGroup,2
make object cube 5,10
position object 5,6,5,25
SC_setupObject 5,TerrainGroup,2

do
  XPos#=object position x(Player)
  YPos#=object position y(Player)
  ZPos#=object position z(Player)

XVel#=0.0
  ZVel#=0.0
  
  `W
  if keystate(17) then inc XVel#,Speed#*sin(object angle y(Player)) : inc ZVel#,Speed#*cos(object angle y(Player))
  `S
  if keystate(31) then dec XVel#,Speed#*sin(object angle y(Player)) : dec ZVel#,Speed#*cos(object angle y(Player))
  `A
  if keystate(30) then inc XVel#,Speed#*sin(object angle y(Player)-90) : inc ZVel#,Speed#*cos(object angle y(Player)-90)
  `D
  if keystate(32) then inc XVel#,Speed#*sin(object angle y(Player)+90) : inc ZVel#,Speed#*cos(object angle y(Player)+90)
  
  dec YVel#,Gravity#
  
  `Test for slope
  Collision=SC_sphereCastGroup(TerrainGroup,XPos#,YPos#,ZPos#,XPos#,YPos#+YVel#,ZPos#,PlayerRadius#,0)
  if Collision
    if abs(SC_getCollisionNormalY())>MaxSlope#
      `We are not on a slope.  Stick to the ground.
      YPos#=SC_getStaticCollisionY()
      YVel#=0
    else
      `We are on a slope.  Slide down it.
      XPos#=SC_getCollisionSlideX()
      YPos#=SC_getCollisionSlideY()
      ZPos#=SC_getCollisionSlideZ()
    endif
  else
    `No collision.  Let the player fall.
    inc YPos#,YVel#
  endif
  
  `Test for walls
  Collision=SC_sphereSlideGroup(TerrainGroup,XPos#,YPos#,ZPos#,XPos#+XVel#,YPos#,ZPos#+ZVel#,PlayerRadius#,0)
  if Collision
    `We hit something.  Slide along the surface.
    XPos#=SC_getCollisionSlideX()
    YPos#=SC_getCollisionSlideY()
    ZPos#=SC_getCollisionSlideZ()
  else
    `No collision.  Move the player normally.
    inc XPos#,XVel#
    inc ZPos#,ZVel#
  endif

+ Code Snippet

`Player
Player=1
PlayerRadius#=2.5
make object sphere Player,2*PlayerRadius#
position object Player,0,50,0
Gravity#=0.1
XVel#=0.0
YVel#=0.0
ZVel#=0.0
Speed#=0.4
MaxSlope#=0.75

`Ground and stuff
TerrainGroup=1
make object box 2,100,2,100
position object 2,0,-1,0
SC_setupObject 2,TerrainGroup,2
make object box 3,1,10,1
position object 3,-.75,5,.75
SC_setupObject 3,TerrainGroup,2
make object cube 4,10
position object 4,-6,5,25
SC_setupObject 4,TerrainGroup,2
make object cube 5,10
position object 5,6,5,25
SC_setupObject 5,TerrainGroup,2

do
  XPos#=object position x(Player)
  YPos#=object position y(Player)
  ZPos#=object position z(Player)

  XVel#=0.0
  ZVel#=0.0
  
  `W
  if keystate(17) then inc XVel#,Speed#*sin(object angle y(Player)) : inc ZVel#,Speed#*cos(object angle y(Player))
  `S
  if keystate(31) then dec XVel#,Speed#*sin(object angle y(Player)) : dec ZVel#,Speed#*cos(object angle y(Player))
  `A
  if keystate(30) then inc XVel#,Speed#*sin(object angle y(Player)-90) : inc ZVel#,Speed#*cos(object angle y(Player)-90)
  `D
  if keystate(32) then inc XVel#,Speed#*sin(object angle y(Player)+90) : inc ZVel#,Speed#*cos(object angle y(Player)+90)
  
  dec YVel#,Gravity#
  
  `Test for slope
  Collision=SC_sphereCastGroup(TerrainGroup,XPos#,YPos#,ZPos#,XPos#,YPos#+YVel#,ZPos#,PlayerRadius#,0)
  if Collision
    if abs(SC_getCollisionNormalY())>MaxSlope#
      `We are not on a slope.  Stick to the ground.
      YPos#=SC_getStaticCollisionY()
      YVel#=0
    else
      `We are on a slope.  Slide down it.
      XPos#=SC_getCollisionSlideX()
      YPos#=SC_getCollisionSlideY()
      ZPos#=SC_getCollisionSlideZ()
    endif
  else
    `No collision.  Let the player fall.
    inc YPos#,YVel#
  endif
  
  `Test for walls
  Collision=SC_sphereSlideGroup(TerrainGroup,XPos#,YPos#,ZPos#,XPos#+XVel#,YPos#,ZPos#+ZVel#,PlayerRadius#,0)
  if Collision
    `We hit something.  Slide along the surface.
    XPos#=SC_getCollisionSlideX()
    YPos#=SC_getCollisionSlideY()
    ZPos#=SC_getCollisionSlideZ()
  else
    `No collision.  Move the player normally.
    inc XPos#,XVel#
    inc ZPos#,ZVel#
  endif

Problem 1

+ Code Snippet

TerrainGroup=1
make object box 2,100,2,100
position object 2,0,-1,0
SC_setupObject 2,TerrainGroup,2
make object box 3,1,10,1
position object 3,-.75,5,.75
SC_setupObject 3,TerrainGroup,2
make object cube 4,10
position object 4,-6,5,25
SC_setupObject 4,TerrainGroup,2
make object cube 5,10
position object 5,6,5,25
SC_setupObject 5,TerrainGroup,2

in that code what does SC_setupObject do and with these 2,TerrainGroup,2 what does that mean?

problem 2:

+ Code Snippet

  if keystate(17) then inc XVel#,Speed#*sin(object angle y(Player)) : inc ZVel#,Speed#*cos(object angle y(Player))
  `S
  if keystate(31) then dec XVel#,Speed#*sin(object angle y(Player)) : dec ZVel#,Speed#*cos(object angle y(Player))
  `A
  if keystate(30) then inc XVel#,Speed#*sin(object angle y(Player)-90) : inc ZVel#,Speed#*cos(object angle y(Player)-90)
  `D
  if keystate(32) then inc XVel#,Speed#*sin(object angle y(Player)+90) : inc ZVel#,Speed#*cos(object angle y(Player)+90)
  
  dec YVel#,Gravity#

in that, I don't undertand these

+ Code Snippet

then inc XVel#,Speed#*sin(object angle y(Player)) : inc ZVel#,Speed#*cos(object angle y(Player))

could you explain that? I don't really understand any of it.

problem 3, this is a big one:

+ Code Snippet

Collision=SC_sphereCastGroup(TerrainGroup,XPos#,YPos#,ZPos#,XPos#,YPos#+YVel#,ZPos#,PlayerRadius#,0)
  if Collision
    if abs(SC_getCollisionNormalY())>MaxSlope#
      `We are not on a slope.  Stick to the ground.
      YPos#=SC_getStaticCollisionY()
      YVel#=0
    else
      `We are on a slope.  Slide down it.
      XPos#=SC_getCollisionSlideX()
      YPos#=SC_getCollisionSlideY()
      ZPos#=SC_getCollisionSlideZ()
    endif
  else
    `No collision.  Let the player fall.
    inc YPos#,YVel#
  endif
  
  `Test for walls
  Collision=SC_sphereSlideGroup(TerrainGroup,XPos#,YPos#,ZPos#,XPos#+XVel#,YPos#,ZPos#+ZVel#,PlayerRadius#,0)
  if Collision
    `We hit something.  Slide along the surface.
    XPos#=SC_getCollisionSlideX()
    YPos#=SC_getCollisionSlideY()
    ZPos#=SC_getCollisionSlideZ()

Pretty much just the way the collision is but i'll point out the main parts in this I don't understand
1.SC_sphereSlideGround
2.TerrainGroup (50-50 understand)
3.SC_getCollisionSlideY()
4.SC_getStaticCollisionY()
5.if abs(SC_getCollisionNormalY())>MaxSlope# (don't get any of that)
6.SC_sphereCastGroup

If anyone could explain those to me (I know it's long) I would VERY much appreciate it. THANKS
If I figure out those 6 things above it should help me alot.

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Hawkblood

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Posted: 6th Aug 2010 15:19

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Sorry I got to the conversation late..... Now that you understand the basics of collisions, you SHOULD go to a .dll like Sparky's. The thing I like about it is that you have more options and more info for collisions.

The fastest code is the code never written.

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Kira Vakaan

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Posted: 6th Aug 2010 20:45 Edited at: 6th Aug 2010 20:46

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@CocaCola: Ah, this is good.

Problem 1:
SC_setupObject has syntax: Object Number, Group Number, and Type of Collision. Basically, it sets up Object Number to be used in collision calculations. The Group Number parameter tells it which group we want to put it in. This isn't really essential, but it makes everything easier to put all of the terrain objects in one group, and then check collision among the entire group. Finally, the Collision Type can have one of three values: 0, 1, and 2 for Polygonal, Sphere, and Box, respectively. Check the help file for more info.

Problem 2:
The keystate function tests for key presses of the key inside the brackets. W, A, S, and D are 17, 30, 31, and 32 respectively. W moves forward, S moves backward, A strafes left, and D strafes right.
How I actually go about doing that is a little more complicated. Right before that section, I set XVel# and ZVel# to 0. These variables are added to the player's position each loop, so they control the player's lateral velocity. The "inc XVel#,Speed#*sin(object angle y(Player)) : inc ZVel#,Speed#*cos(object angle y(Player))" part increases the X and Z velocities a certain amount based on the speed of the player, and the direction the player is facing. I use some simple trig to do this, but you could also use DBPro's newxvalue (and y and z) commands to do that for you. I just prefer the math.
The "dec YVel#,Gravity#" part simply subtracts the acceleration due to gravity from the Y velocity.

Problem 3:
Here, I'll write in a lot of comments to the code:

`SC_sphereCastGroup moves an imaginary sphere with a radius of PlayerRadius# from XPos#,YPos#,ZPos# to XPos#,YPos#+YVel#,ZPos#
  `and checks for collisions along the way.  We want to check collisions with all objects in the TerrainGroup group.
  Collision=SC_sphereCastGroup(TerrainGroup,XPos#,YPos#,ZPos#,XPos#,YPos#+YVel#,ZPos#,PlayerRadius#,0)
  `If there was a collision...
  if Collision
    `After calling SC_sphereCastGroup, Sparky's stores information about the previous collision.  We can use certain commands to retrieve that information.
    `SC_getCollisionNormalY gets the Y component of the normal of the polygon the imaginary sphere collided with.  The "normal" of a polygon is basically
    `a vector that points in the direction that the polygon is facing.  Thus, if the Y component of the normal is 1.0, the polygon is completely horizontal (a floor),
    `whereas if the Y component is 0.0, the polygon is completely vertical (a wall).  We use the collision normal to determine how sloped the surface we're touching
    `is.  MaxSlope# contains the value past which we call the surface "flat" enough to walk on.
    if abs(SC_getCollisionNormalY())>MaxSlope#
      `We are not on a slope.  Stick to the ground.
      `SC_getStaticCollisionY returns the Y coordinate of the imaginary sphere if it were to stick to the polygon it collided with.
      YPos#=SC_getStaticCollisionY()
      YVel#=0
    else
      `We are on a slope.  Slide down it.
      `SC_getCollisionSlideX, Y, and Z return the coordinates of the imaginary sphere if we were to slide along the polygon we collided with.
      XPos#=SC_getCollisionSlideX()
      YPos#=SC_getCollisionSlideY()
      ZPos#=SC_getCollisionSlideZ()
    endif
  else
    `No collision.  Let the player fall.
    `If the imaginary sphere didn't collide with anything, we know that if is safe to add the Y velocity to the Y position.  Afterall, that's the path that we were testing.
    inc YPos#,YVel#
  endif
  
  `Test for walls
  `Here we use SC_sphereSlideGroup instead of SC_sphereCastGroup because SC_sphereSlide group provides more accurate sliding collision
  `data (that is, the position of the imaginary sphere if it were to slide along any polygon it hits).
  `Since we've already changed the Y position, we only need to test collision while applying the X and Z velocities.  Basically, we're
  `testing for collision with walls.
  `We use SC_sphereSlideGroup because we never want to "stick" to a wall.  We always want to slide along it.
  Collision=SC_sphereSlideGroup(TerrainGroup,XPos#,YPos#,ZPos#,XPos#+XVel#,YPos#,ZPos#+ZVel#,PlayerRadius#,0)
  if Collision
    `We hit something.  Slide along the surface.
    XPos#=SC_getCollisionSlideX()
    YPos#=SC_getCollisionSlideY()
    ZPos#=SC_getCollisionSlideZ()

+ Code Snippet

  `SC_sphereCastGroup moves an imaginary sphere with a radius of PlayerRadius# from XPos#,YPos#,ZPos# to XPos#,YPos#+YVel#,ZPos#
  `and checks for collisions along the way.  We want to check collisions with all objects in the TerrainGroup group.
  Collision=SC_sphereCastGroup(TerrainGroup,XPos#,YPos#,ZPos#,XPos#,YPos#+YVel#,ZPos#,PlayerRadius#,0)
  `If there was a collision...
  if Collision
    `After calling SC_sphereCastGroup, Sparky's stores information about the previous collision.  We can use certain commands to retrieve that information.
    `SC_getCollisionNormalY gets the Y component of the normal of the polygon the imaginary sphere collided with.  The "normal" of a polygon is basically
    `a vector that points in the direction that the polygon is facing.  Thus, if the Y component of the normal is 1.0, the polygon is completely horizontal (a floor),
    `whereas if the Y component is 0.0, the polygon is completely vertical (a wall).  We use the collision normal to determine how sloped the surface we're touching
    `is.  MaxSlope# contains the value past which we call the surface "flat" enough to walk on.
    if abs(SC_getCollisionNormalY())>MaxSlope#
      `We are not on a slope.  Stick to the ground.
      `SC_getStaticCollisionY returns the Y coordinate of the imaginary sphere if it were to stick to the polygon it collided with.
      YPos#=SC_getStaticCollisionY()
      YVel#=0
    else
      `We are on a slope.  Slide down it.
      `SC_getCollisionSlideX, Y, and Z return the coordinates of the imaginary sphere if we were to slide along the polygon we collided with.
      XPos#=SC_getCollisionSlideX()
      YPos#=SC_getCollisionSlideY()
      ZPos#=SC_getCollisionSlideZ()
    endif
  else
    `No collision.  Let the player fall.
    `If the imaginary sphere didn't collide with anything, we know that if is safe to add the Y velocity to the Y position.  Afterall, that's the path that we were testing.
    inc YPos#,YVel#
  endif
  
  `Test for walls
  `Here we use SC_sphereSlideGroup instead of SC_sphereCastGroup because SC_sphereSlide group provides more accurate sliding collision
  `data (that is, the position of the imaginary sphere if it were to slide along any polygon it hits).
  `Since we've already changed the Y position, we only need to test collision while applying the X and Z velocities.  Basically, we're
  `testing for collision with walls.
  `We use SC_sphereSlideGroup because we never want to "stick" to a wall.  We always want to slide along it.
  Collision=SC_sphereSlideGroup(TerrainGroup,XPos#,YPos#,ZPos#,XPos#+XVel#,YPos#,ZPos#+ZVel#,PlayerRadius#,0)
  if Collision
    `We hit something.  Slide along the surface.
    XPos#=SC_getCollisionSlideX()
    YPos#=SC_getCollisionSlideY()
    ZPos#=SC_getCollisionSlideZ()

I hope that helps. If you need clarification on any segment, feel free to ask, but first check the Sparky's DLL help files for how the commands work.

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CocaCola

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Posted: 6th Aug 2010 20:46 Edited at: 6th Aug 2010 20:48

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Quote: "Sorry I got to the conversation late..... Now that you understand the basics of collisions, you SHOULD go to a .dll like Sparky's. The thing I like about it is that you have more options and more info for collisions."

Ok, thanks I'm trying.

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CocaCola

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Posted: 6th Aug 2010 20:51 Edited at: 6th Aug 2010 20:52

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doesn't this not work well? (My other way doesn't fix it but this is kind of doing the same thing)

+ Code Snippet

SC_setupObject has syntax: Object Number, Group Number, and Type of 
Collision. Basically, it sets up Object Number to be used in collision 
calculations. The Group Number parameter tells it which group we want to 
put it in. This isn't really essential, but it makes everything easier to 
put all of the terrain objects in one group, and then check collision 
among the entire group. Finally, the Collision Type can have one of three 
values: 0, 1, and 2 for Polygonal, Sphere, and Box, respectively. Check 
the help file for more info.

so if I had a player I would have to choose if a box, sphere, or polygonal is best for collision? wouldn't that make it so if you had something like this

and you tried to go through the hole where you put your hand you couldn't?

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Kira Vakaan

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Posted: 6th Aug 2010 22:14

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In my code, I never actually setup the player object (object 1) for collision. This is because there is no need to. When we check for collision between the player and other objects, we don't actually use the player's object. We just create an imaginary sphere around where the player is and use that instead. This is a common misconception for newcomers to Sparky's. The only time we would need to setup the player's object for collision would be if we need to check for collision between other objects and the player (which is different from "the player and other objects"), or when the player is not moving, but other objects are moving toward the player.

If you have complex terrain, you should set that up as polygonal, and actually, it would probably be better to use the SC_setupComplexObject command.

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CocaCola

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Posted: 7th Aug 2010 01:10

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Quote: "SC_setupComplexObject"

and whats that do?

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Kira Vakaan

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Posted: 7th Aug 2010 01:18

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It sets up polygon-based collision for an object by using an octree structure to efficiently divide up an object for quicker collision detection. It's useful for objects with high poly counts.

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DarkBASIC Professional Discussion / Why won't this collision testing code work? (No sparkys)