Ray cast problems... - GameCreators Forum

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Chiblue

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Posted: 23rd Jan 2010 03:36

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Here is my problem, I am using DP for my Ray cast, this is my problem.. I have a wall which is about twice the height of the player... when I shoot at the wall (this is mapped as a rigid static mesh in DP)... I may or maynot get my bullet holes... but then when I shoot at different spoke on the wall, I get bullet holes...

When I dump the variables to a file my vectors are consistent, but the object it is hitting when I am not hitting the wall is a long way behind the way... i.e. z=5000, instead if z=100...

Can someone help with sopme suggestions...

This is how I am registering the wall in DP.

+ Code Snippet

Phy Make rigid body static mesh limb

This is my ray cast code...

+ Code Snippet

x1#=camera position x()
y1#=camera position x()
z1#=camera position x()
move camera 1
x2#=camera position x()
y2#=camera position x()
z2#=camera position x()
move camera -1
rx# = x2# - x1#
ry# = y2# - y1#
rz# = z2# - z1#
l# = sqrt(rx# ^ 2 + ry# ^ 2 + rz# ^ 2)
rx# = (x2# - x1#)/l#
ry# = (y2# - y1#)/l#
rz# = (z2# - z1#)/l#
temphit# = phy ray cast all shapes(x1#, y1#, z1#, rx#, ry#, rz#)
if phy get ray cast hit() = 1
    objectdist#=phy get ray cast distance()
    objecthit#=phy get ray cast object()
endif

in this example the wall is object say 6, which when I get a bullet hole is the collision object, but when I do not I get other objects other than 6, and the hit distance is 4000+ instead of <100 when I hit 6.

This is my last attempt at using DP for this, I have struggled with this now for several days... Please do not respond telling me I should use sparky or NGC, NGC ray cast SUCKS, and sparkys does not have the physics control I need... I tried using Sparky and DP but to get the sparky ray cast working I have to register all my objects with Sparky, but then the DP engine cannot move them unless I perform sc_update on the objects to allow them to reposition...

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HowDo

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Posted: 23rd Jan 2010 12:04 Edited at: 23rd Jan 2010 12:07

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welcome to physx beast, sound like you got a long way and this bit needs some help.

I'll try to help first off do you use and have the Visual debugger if not click on the link.
replace
l# = sqrt(rx# ^ 2 + ry# ^ 2 + rz# ^ 2)
with this
l# = vectorlength( rx#,ry#,rz#)

my bad, helps if I read all of some else code, looks like you are doing that bit right with first line.

worth a look at the linki below unless this where you got it from.

code found here for more info.

Dark Physics makes any hot drink go cold.

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Chiblue

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Posted: 23rd Jan 2010 15:06

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Thanks for the info, yes have building my own normalization routine for the vectors, and having the same issue, I tried the info in this forum post... I did not understand this part...

Quote: "and use the first 4 numbers

a# = 0.7071
b# = -0.7071

in 'value = phy ray cast all shapes ( x#, y#, z#, a#, b#, 0)'
the ray cast still works, BUT if you change the numbers

e.g. :
a# = 0.707 and b# = -0.707
or
a# = 0.7072 and b# = -0.7072

the ray cast ceases funtioning.
"

When I use the normal float result it works on most surfaces.,.. Yes I have the debug tool and checked all bounding surfaces and everything looks find... on those objects that fail to get a raycast response, I still get collisions with my character..

Given the other stuff I am going, DP helps a lot, but without the raycat I am out of luck using it as a solution.. Funny thing is, this is the only collision system that does not have a FPS type shooting example.. my thought is that even TGC know they have a problem with this, unless I am completely wrong.. The strange and frustrating thing is that it works on an object 90% but then for somew reason certaion parts will not work..

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HowDo

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Posted: 23rd Jan 2010 15:12 Edited at: 23rd Jan 2010 15:14

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if you can try changing your code to use the while endwhile system as shown in the chm guide, because you are using the if statement it may have missed the collision.

plus form what saw in that like i would use the cos sin math for it in instead of direct numbers.

Dark Physics makes any hot drink go cold.

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Chiblue

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Posted: 24th Jan 2010 03:56

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I don't see a while/endwhile in the forum post code, all I see is an if...

+ Code Snippet

  rem value = phy ray cast all shapes ( x#, y#, z#, 0, -1, 0 )
   value = phy ray cast all shapes ( x#, y#, z#, rx#, ry#, rz# )

   ` if the ray hit something then colour that object blue
   if phy get ray cast hit( )= 1
        color object phy get ray cast object ( ), rgb ( 0, 0, 255 )
   endif

This is inside a function called by the main loop... or am I missing something..

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HowDo

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Posted: 24th Jan 2010 12:21

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you're correct there nothing about a while endwhile in your code.

I am on about the shooting demo in the resource files that come with PhysX, there it show how to use the collision system and what errors you may get if use wrongly.

Dark Physics makes any hot drink go cold.

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Chiblue

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Posted: 25th Jan 2010 16:29

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Maybe I am missing something but I do not have a shooting demo in my Physx folder?

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HowDo

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Posted: 25th Jan 2010 17:26 Edited at: 25th Jan 2010 17:27

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found in the information file. under getting started.

look like this.

Dark Physics makes any hot drink go cold.

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Chiblue

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Posted: 25th Jan 2010 20:26

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I took the ray cast example and modified it to add additional boxes, changed 3 to use static mesh and 3 to use static box, I then offset them and rotated them randomly to create different normals... It works perfectly see code...I even changed the order of the object numbers i.e. lowest on top, highest on bottom.. I even changed the object creation order so the lowest were created first and vise versa... still appears to be working correclty.. obviously these are simple shapes, but with the static mess it should represent different impact locations and normals...

phy start
autocam off
sync on
sync rate 60
color backdrop 0
position camera 0, 20, -70

` create some objects
make object cube 11, 5
position object 11, -5, 0, 0
Rotate Object 11,rnd(90),rnd(90),rnd(90)
phy make rigid body static mesh 11

make object cube 12, 5
position object 12, -15, 0, 0
Rotate Object 12,rnd(90),rnd(90),rnd(90)
phy make rigid body static mesh 12

make object cube 13, 5
position object 13, 15, 0, 0
Rotate Object 13,rnd(90),rnd(90),rnd(90)
phy make rigid body static mesh 13

make object cube 1, 5
position object 1, 0, -10, 0
Rotate Object 1,rnd(90),rnd(90),rnd(90)
phy make rigid body static box 1

make object cube 2, 5
position object 2, -20, -10, 0
Rotate Object 2,rnd(90),rnd(90),rnd(90)
phy make rigid body static box 2

make object cube 3, 5
position object 3, 20, -10, 0
Rotate Object 3,rnd(90),rnd(90),rnd(90)
phy make rigid body static box 3

make object cube 4, 5
position object 4, 0, 20, 0
make object box 5, 1, 15, 1
position object 5, 0, 15, 0
texture object 4,1
texture object 5,1
` main program loop
do
   ` display information

` set all objects to black
   for i = 1 to 3
      color object i, 0
   next i
   for i = 11 to 13
      color object i, 0
   next i

` get the position of object 4
   x# = object position x ( 4 )
   y# = object position y ( 4 )
   z# = object position z ( 4 )

` cast a ray down
   value = phy ray cast all shapes ( x#, y#, z#, 0, -1, 0 )

` if the ray hit something then colour that object blue
   if phy get ray cast hit( )= 1
        color object phy get ray cast object ( ), rgb ( 0, 0, 255 )

text 0,80,"object: " + str$(phy get ray cast object() )
        text 0,100,"Dist: " + str$(phy get ray cast distance() )
        text 0,120,"normal x: " + str$(phy get ray cast hit normal x())
        text 0,140,"normal y: " + str$(phy get ray cast hit normal y())
        text 0,160,"normal z: " + str$(phy get ray cast hit normal z())
        text 0,180,"point x: " + str$(phy get ray cast hit point x())
        text 0,200,"point y: " + str$(phy get ray cast hit point y())
        text 0,220,"point z: " + str$(phy get ray cast hit point z())

endif

`move the ray cast left
   if leftkey ( )
      move object left 4, 0.4
      move object left 5, 0.4
   endif

` mvoe the ray cast right
   if rightkey ( )
      move object right 4, 0.4
      move object right 5, 0.4
   endif

` update the simulation and screen
   phy update
   sync
loop

+ Code Snippet

phy start
autocam off
sync on
sync rate 60
color backdrop 0
position camera 0, 20, -70

` create some objects
make object cube 11, 5
position object 11, -5, 0, 0
Rotate Object 11,rnd(90),rnd(90),rnd(90)
phy make rigid body static mesh 11

make object cube 12, 5
position object 12, -15, 0, 0
Rotate Object 12,rnd(90),rnd(90),rnd(90)
phy make rigid body static mesh 12

make object cube 13, 5
position object 13, 15, 0, 0
Rotate Object 13,rnd(90),rnd(90),rnd(90)
phy make rigid body static mesh 13

make object cube 1, 5
position object 1, 0, -10, 0
Rotate Object 1,rnd(90),rnd(90),rnd(90)
phy make rigid body static box 1

make object cube 2, 5
position object 2, -20, -10, 0
Rotate Object 2,rnd(90),rnd(90),rnd(90)
phy make rigid body static box 2

make object cube 3, 5
position object 3, 20, -10, 0
Rotate Object 3,rnd(90),rnd(90),rnd(90)
phy make rigid body static box 3

make object cube 4, 5
position object 4, 0, 20, 0
make object box 5, 1, 15, 1
position object 5, 0, 15, 0
texture object 4,1
texture object 5,1
` main program loop
do
   ` display information

   ` set all objects to black
   for i = 1 to 3
      color object i, 0
   next i
   for i = 11 to 13
      color object i, 0
   next i

   ` get the position of object 4
   x# = object position x ( 4 )
   y# = object position y ( 4 )
   z# = object position z ( 4 )

   ` cast a ray down
   value = phy ray cast all shapes ( x#, y#, z#, 0, -1, 0 )

   ` if the ray hit something then colour that object blue
   if phy get ray cast hit( )= 1
        color object phy get ray cast object ( ), rgb ( 0, 0, 255 )

        text 0,80,"object: " + str$(phy get ray cast object() )
        text 0,100,"Dist: " + str$(phy get ray cast distance() )
        text 0,120,"normal x: " + str$(phy get ray cast hit normal x())
        text 0,140,"normal y: " + str$(phy get ray cast hit normal y())
        text 0,160,"normal z: " + str$(phy get ray cast hit normal z())
        text 0,180,"point x: " + str$(phy get ray cast hit point x())
        text 0,200,"point y: " + str$(phy get ray cast hit point y())
        text 0,220,"point z: " + str$(phy get ray cast hit point z())

   endif

   `move the ray cast left
   if leftkey ( )
      move object left 4, 0.4
      move object left 5, 0.4
   endif

   ` mvoe the ray cast right
   if rightkey ( )
      move object right 4, 0.4
      move object right 5, 0.4
   endif

   ` update the simulation and screen
   phy update
   sync
loop

As far as I can tell Ray cast is working as expected in this example, so I must be doing something wrong in my code, but what.... any thoughts? this does however give me some confidence in the Ray cast solution.. I prefer it being my problem..

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HowDo

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Posted: 25th Jan 2010 20:53

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I had ago at changing it to use the while command system and it now can show two boxes at a time?

have a look. might be me noyt understanding the code.