Mathematically Locking Object to Camera With Offsets

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Milkman

18

Years of Service

User Offline

Joined: 30th Nov 2005

Location: United States

Posted: 4th Feb 2007 06:45 Edited at: 21st Mar 2007 05:32

Link

This does exactly what the title says. I worked on this for another thread, and thought I'd post it here. Could be very useful for a lot of things

Base code:

+ Code Snippet

   sx = sin(camAngleX) : cx = cos(camAngleX)
   sy = sin(camAngleY) : cy = cos(camAngleY)
   sz = sin(camAngleZ) : cz = cos(camAngleZ)
   xPos = camPosX + xOffset*(cy*cz) + yOffset*(sx*sy*cz-cx*sz) + zOffset*(cx*sy*cz+sx*sz)
   yPos = camPosY + xOffset*(cy*sz) + yOffset*(cx*cz+sx*sy*sz) + zOffset*(cx*sy*sz-sx*cz)
   zPos = camPosZ + xOffset*(-sy) + yOffset*(sx*cy) + zOffset*(cx*cy)

An explaination of the variables:

All variables are floats. sx, sy, sz, cx, cy, cz just store the sine/cosine values of the camera angles. camAngleX, camAngleY, camAngleZ represent the camera's current angles of rotation. camPosX, camPosY, camPosZ represent the camera's current position. xOffset, yOffset, zOffset are the offset values relative to the camera. xPos, yPos, and zPos are the coordinates at which the object should be positioned.

EDIT:

Here are the three functions that were made from this code:
lockObjectToCamera(object, xOffset, yOffset, zOffset)
lockObjectToObject(object, baseObj, xOffset, yOffset, zOffset)
lockCameraToObject(camera, baseObj, xOffset, yOffset, zOffset)

`locks an object to the screen with offsets
function lockObjectToCamera(object as dword,xOff as float,yOff as float,zOff as float)
   sx as float : sy as float : sz as float
   cx as float : cy as float : cz as float
   xPos as float : yPos as float : zPos as float
   sx = sin(camera angle x()) : cx = cos(camera angle x())
   sy = sin(camera angle y()) : cy = cos(camera angle y())
   sz = sin(camera angle z()) : cz = cos(camera angle z())
   xPos = camera position x() + xOff*(cy*cz) + yOff*(sx*sy*cz-cx*sz) + zOff*(cx*sy*cz+sx*sz)
   yPos = camera position y() + xOff*(cy*sz) + yOff*(cx*cz+sx*sy*sz) + zOff*(cx*sy*sz-sx*cz)
   zPos = camera position z() + xOff*(-1*sy) + yOff*(sx*cy) + zOff*(cx*cy)
   position object object,xPos,yPos,zPos
   set object to camera orientation object
endfunction

`locks an object to another object, with offsets
function lockObjectToObject(object as dword,lockTo as dword,xOff as float,yOff as float,zOff as float)
   sx as float : sy as float : sz as float
   cx as float : cy as float : cz as float
   xPos as float : yPos as float : zPos as float
   sx = sin(object angle x(lockTo)) : cx = cos(object angle x(lockTo))
   sy = sin(object angle y(lockTo)) : cy = cos(object angle y(lockTo))
   sz = sin(object angle z(lockTo)) : cz = cos(object angle z(lockTo))
   xPos = object position x(lockTo) + xOff*(cy*cz) + yOff*(sx*sy*cz-cx*sz) + zOff*(cx*sy*cz+sx*sz)
   yPos = object position y(lockTo) + xOff*(cy*sz) + yOff*(cx*cz+sx*sy*sz) + zOff*(cx*sy*sz-sx*cz)
   zPos = object position z(lockTo) + xOff*(-1*sy) + yOff*(sx*cy) + zOff*(cx*cy)
   position object object,xPos,yPos,zPos
   set object to object orientation object,lockTo
endfunction

`locks a camera to object, with offsets
function lockCameraToObject(camera as dword,lockTo as dword,xOff as float,yOff as float,zOff as float)
   sx as float : sy as float : sz as float
   cx as float : cy as float : cz as float
   xPos as float : yPos as float : zPos as float
   sx = sin(object angle x(lockTo)) : cx = cos(object angle x(lockTo))
   sy = sin(object angle y(lockTo)) : cy = cos(object angle y(lockTo))
   sz = sin(object angle z(lockTo)) : cz = cos(object angle z(lockTo))
   xPos = object position x(lockTo) + xOff*(cy*cz) + yOff*(sx*sy*cz-cx*sz) + zOff*(cx*sy*cz+sx*sz)
   yPos = object position y(lockTo) + xOff*(cy*sz) + yOff*(cx*cz+sx*sy*sz) + zOff*(cx*sy*sz-sx*cz)
   zPos = object position z(lockTo) + xOff*(-1*sy) + yOff*(sx*cy) + zOff*(cx*cy)
   position camera camera,xPos,yPos,zPos
   set camera to object orientation camera,lockTo
endfunction

+ Code Snippet

`locks an object to the screen with offsets
function lockObjectToCamera(object as dword,xOff as float,yOff as float,zOff as float)
   sx as float : sy as float : sz as float
   cx as float : cy as float : cz as float
   xPos as float : yPos as float : zPos as float
   sx = sin(camera angle x()) : cx = cos(camera angle x())
   sy = sin(camera angle y()) : cy = cos(camera angle y())
   sz = sin(camera angle z()) : cz = cos(camera angle z())
   xPos = camera position x() + xOff*(cy*cz) + yOff*(sx*sy*cz-cx*sz) + zOff*(cx*sy*cz+sx*sz)
   yPos = camera position y() + xOff*(cy*sz) + yOff*(cx*cz+sx*sy*sz) + zOff*(cx*sy*sz-sx*cz)
   zPos = camera position z() + xOff*(-1*sy) + yOff*(sx*cy) + zOff*(cx*cy)
   position object object,xPos,yPos,zPos
   set object to camera orientation object
endfunction

`locks an object to another object, with offsets
function lockObjectToObject(object as dword,lockTo as dword,xOff as float,yOff as float,zOff as float)
   sx as float : sy as float : sz as float
   cx as float : cy as float : cz as float
   xPos as float : yPos as float : zPos as float
   sx = sin(object angle x(lockTo)) : cx = cos(object angle x(lockTo))
   sy = sin(object angle y(lockTo)) : cy = cos(object angle y(lockTo))
   sz = sin(object angle z(lockTo)) : cz = cos(object angle z(lockTo))
   xPos = object position x(lockTo) + xOff*(cy*cz) + yOff*(sx*sy*cz-cx*sz) + zOff*(cx*sy*cz+sx*sz)
   yPos = object position y(lockTo) + xOff*(cy*sz) + yOff*(cx*cz+sx*sy*sz) + zOff*(cx*sy*sz-sx*cz)
   zPos = object position z(lockTo) + xOff*(-1*sy) + yOff*(sx*cy) + zOff*(cx*cy)
   position object object,xPos,yPos,zPos
   set object to object orientation object,lockTo
endfunction

`locks a camera to object, with offsets
function lockCameraToObject(camera as dword,lockTo as dword,xOff as float,yOff as float,zOff as float)
   sx as float : sy as float : sz as float
   cx as float : cy as float : cz as float
   xPos as float : yPos as float : zPos as float
   sx = sin(object angle x(lockTo)) : cx = cos(object angle x(lockTo))
   sy = sin(object angle y(lockTo)) : cy = cos(object angle y(lockTo))
   sz = sin(object angle z(lockTo)) : cz = cos(object angle z(lockTo))
   xPos = object position x(lockTo) + xOff*(cy*cz) + yOff*(sx*sy*cz-cx*sz) + zOff*(cx*sy*cz+sx*sz)
   yPos = object position y(lockTo) + xOff*(cy*sz) + yOff*(cx*cz+sx*sy*sz) + zOff*(cx*sy*sz-sx*cz)
   zPos = object position z(lockTo) + xOff*(-1*sy) + yOff*(sx*cy) + zOff*(cx*cy)
   position camera camera,xPos,yPos,zPos
   set camera to object orientation camera,lockTo
endfunction

Here's a no media example for dbp (just copy, paste, and run):

sync on : sync rate 0
autocam off
hide mouse
rate as float

`types
type vector
   x as float = 0.0
   y as float = 0.0
   z as float = 0.0
endtype
type camera
   pos as vector
   rot as vector
endtype

`make camera
cam as camera
position camera 40.0,1.0,40.0
point camera 0,0,0
cam.pos.x=camera position x()
cam.pos.y=camera position y()
cam.pos.z=camera position z()
cam.rot.x=camera angle x()
cam.rot.y=camera angle y()
cam.rot.z=camera angle z()

`make level
level as dword = 1
make matrix level,100.0,100.0,20,20
set matrix level,1,0,1,1,1,1,1
position matrix level,-50.0,0,-50.0

`make gun
gun as dword = 2
make object box gun,0.2,0.2,0.5

`make spinning object
boxObj as dword = 3
make object box boxObj,1.0,1.5,2.5
position object boxObj,35.0,2.0,35.0

do
   `rate scale value
   rate=(10.0/screen fps())

`handle camera
   cam.rot.x=cam.rot.x+mousemovey()*rate*2.0
   cam.rot.y=cam.rot.y+mousemovex()*rate*2.0
   cam.pos.x=cam.pos.x + cos(cam.rot.x)*sin(cam.rot.y)*rate*0.5*(keystate(17)-keystate(31)) + newxvalue(0.0,cam.rot.y-90,rate*0.5*(keystate(30)-keystate(32)))
   cam.pos.y=cam.pos.y - sin(cam.rot.x)*rate*0.5*(keystate(17)-keystate(31))
   cam.pos.z=cam.pos.z + cos(cam.rot.x)*cos(cam.rot.y)*rate*0.5*(keystate(17)-keystate(31)) + newzvalue(0.0,cam.rot.y-90,rate*0.5*(keystate(30)-keystate(32)))
   rotate camera cam.rot.x,cam.rot.y,cam.rot.z
   position camera cam.pos.x,cam.pos.y,cam.pos.z

`rotate box
   rotate object boxObj,object angle x(boxObj)+2.5*rate,object angle y(boxObj)+2.5*rate,object angle z(boxObj)+2.5*rate

`use of locking functions
   lockObjectToCamera(gun,0.3,-0.3,1.4)
   `lockObjectToObject(gun,boxObj,0.5,1.0,1.5)
   `lockCameraToObject(0,boxObj,0.5,1.0,-2.5)
   sync
loop

`locks an object to the screen with offsets
function lockObjectToCamera(object as dword,xOff as float,yOff as float,zOff as float)
   sx as float : sy as float : sz as float
   cx as float : cy as float : cz as float
   xPos as float : yPos as float : zPos as float
   sx = sin(camera angle x()) : cx = cos(camera angle x())
   sy = sin(camera angle y()) : cy = cos(camera angle y())
   sz = sin(camera angle z()) : cz = cos(camera angle z())
   xPos = camera position x() + xOff*(cy*cz) + yOff*(sx*sy*cz-cx*sz) + zOff*(cx*sy*cz+sx*sz)
   yPos = camera position y() + xOff*(cy*sz) + yOff*(cx*cz+sx*sy*sz) + zOff*(cx*sy*sz-sx*cz)
   zPos = camera position z() + xOff*(-1*sy) + yOff*(sx*cy) + zOff*(cx*cy)
   position object object,xPos,yPos,zPos
   set object to camera orientation object
endfunction

`locks an object to another object, with offsets
function lockObjectToObject(object as dword,lockTo as dword,xOff as float,yOff as float,zOff as float)
   sx as float : sy as float : sz as float
   cx as float : cy as float : cz as float
   xPos as float : yPos as float : zPos as float
   sx = sin(object angle x(lockTo)) : cx = cos(object angle x(lockTo))
   sy = sin(object angle y(lockTo)) : cy = cos(object angle y(lockTo))
   sz = sin(object angle z(lockTo)) : cz = cos(object angle z(lockTo))
   xPos = object position x(lockTo) + xOff*(cy*cz) + yOff*(sx*sy*cz-cx*sz) + zOff*(cx*sy*cz+sx*sz)
   yPos = object position y(lockTo) + xOff*(cy*sz) + yOff*(cx*cz+sx*sy*sz) + zOff*(cx*sy*sz-sx*cz)
   zPos = object position z(lockTo) + xOff*(-1*sy) + yOff*(sx*cy) + zOff*(cx*cy)
   position object object,xPos,yPos,zPos
   set object to object orientation object,lockTo
endfunction

`locks a camera to object, with offsets
function lockCameraToObject(camera as dword,lockTo as dword,xOff as float,yOff as float,zOff as float)
   sx as float : sy as float : sz as float
   cx as float : cy as float : cz as float
   xPos as float : yPos as float : zPos as float
   sx = sin(object angle x(lockTo)) : cx = cos(object angle x(lockTo))
   sy = sin(object angle y(lockTo)) : cy = cos(object angle y(lockTo))
   sz = sin(object angle z(lockTo)) : cz = cos(object angle z(lockTo))
   xPos = object position x(lockTo) + xOff*(cy*cz) + yOff*(sx*sy*cz-cx*sz) + zOff*(cx*sy*cz+sx*sz)
   yPos = object position y(lockTo) + xOff*(cy*sz) + yOff*(cx*cz+sx*sy*sz) + zOff*(cx*sy*sz-sx*cz)
   zPos = object position z(lockTo) + xOff*(-1*sy) + yOff*(sx*cy) + zOff*(cx*cy)
   position camera camera,xPos,yPos,zPos
   set camera to object orientation camera,lockTo
endfunction

+ Code Snippet

sync on : sync rate 0
autocam off
hide mouse
rate as float



`types
type vector
   x as float = 0.0
   y as float = 0.0
   z as float = 0.0
endtype
type camera
   pos as vector
   rot as vector
endtype



`make camera
cam as camera
position camera 40.0,1.0,40.0
point camera 0,0,0
cam.pos.x=camera position x()
cam.pos.y=camera position y()
cam.pos.z=camera position z()
cam.rot.x=camera angle x()
cam.rot.y=camera angle y()
cam.rot.z=camera angle z()



`make level
level as dword = 1
make matrix level,100.0,100.0,20,20
set matrix level,1,0,1,1,1,1,1
position matrix level,-50.0,0,-50.0



`make gun
gun as dword = 2
make object box gun,0.2,0.2,0.5



`make spinning object
boxObj as dword = 3
make object box boxObj,1.0,1.5,2.5
position object boxObj,35.0,2.0,35.0



do
   `rate scale value
   rate=(10.0/screen fps())

   `handle camera
   cam.rot.x=cam.rot.x+mousemovey()*rate*2.0
   cam.rot.y=cam.rot.y+mousemovex()*rate*2.0
   cam.pos.x=cam.pos.x + cos(cam.rot.x)*sin(cam.rot.y)*rate*0.5*(keystate(17)-keystate(31)) + newxvalue(0.0,cam.rot.y-90,rate*0.5*(keystate(30)-keystate(32)))
   cam.pos.y=cam.pos.y - sin(cam.rot.x)*rate*0.5*(keystate(17)-keystate(31))
   cam.pos.z=cam.pos.z + cos(cam.rot.x)*cos(cam.rot.y)*rate*0.5*(keystate(17)-keystate(31)) + newzvalue(0.0,cam.rot.y-90,rate*0.5*(keystate(30)-keystate(32)))
   rotate camera cam.rot.x,cam.rot.y,cam.rot.z
   position camera cam.pos.x,cam.pos.y,cam.pos.z

   `rotate box
   rotate object boxObj,object angle x(boxObj)+2.5*rate,object angle y(boxObj)+2.5*rate,object angle z(boxObj)+2.5*rate

   `use of locking functions
   lockObjectToCamera(gun,0.3,-0.3,1.4)
   `lockObjectToObject(gun,boxObj,0.5,1.0,1.5)
   `lockCameraToObject(0,boxObj,0.5,1.0,-2.5)
   sync
loop



`locks an object to the screen with offsets
function lockObjectToCamera(object as dword,xOff as float,yOff as float,zOff as float)
   sx as float : sy as float : sz as float
   cx as float : cy as float : cz as float
   xPos as float : yPos as float : zPos as float
   sx = sin(camera angle x()) : cx = cos(camera angle x())
   sy = sin(camera angle y()) : cy = cos(camera angle y())
   sz = sin(camera angle z()) : cz = cos(camera angle z())
   xPos = camera position x() + xOff*(cy*cz) + yOff*(sx*sy*cz-cx*sz) + zOff*(cx*sy*cz+sx*sz)
   yPos = camera position y() + xOff*(cy*sz) + yOff*(cx*cz+sx*sy*sz) + zOff*(cx*sy*sz-sx*cz)
   zPos = camera position z() + xOff*(-1*sy) + yOff*(sx*cy) + zOff*(cx*cy)
   position object object,xPos,yPos,zPos
   set object to camera orientation object
endfunction

`locks an object to another object, with offsets
function lockObjectToObject(object as dword,lockTo as dword,xOff as float,yOff as float,zOff as float)
   sx as float : sy as float : sz as float
   cx as float : cy as float : cz as float
   xPos as float : yPos as float : zPos as float
   sx = sin(object angle x(lockTo)) : cx = cos(object angle x(lockTo))
   sy = sin(object angle y(lockTo)) : cy = cos(object angle y(lockTo))
   sz = sin(object angle z(lockTo)) : cz = cos(object angle z(lockTo))
   xPos = object position x(lockTo) + xOff*(cy*cz) + yOff*(sx*sy*cz-cx*sz) + zOff*(cx*sy*cz+sx*sz)
   yPos = object position y(lockTo) + xOff*(cy*sz) + yOff*(cx*cz+sx*sy*sz) + zOff*(cx*sy*sz-sx*cz)
   zPos = object position z(lockTo) + xOff*(-1*sy) + yOff*(sx*cy) + zOff*(cx*cy)
   position object object,xPos,yPos,zPos
   set object to object orientation object,lockTo
endfunction

`locks a camera to object, with offsets
function lockCameraToObject(camera as dword,lockTo as dword,xOff as float,yOff as float,zOff as float)
   sx as float : sy as float : sz as float
   cx as float : cy as float : cz as float
   xPos as float : yPos as float : zPos as float
   sx = sin(object angle x(lockTo)) : cx = cos(object angle x(lockTo))
   sy = sin(object angle y(lockTo)) : cy = cos(object angle y(lockTo))
   sz = sin(object angle z(lockTo)) : cz = cos(object angle z(lockTo))
   xPos = object position x(lockTo) + xOff*(cy*cz) + yOff*(sx*sy*cz-cx*sz) + zOff*(cx*sy*cz+sx*sz)
   yPos = object position y(lockTo) + xOff*(cy*sz) + yOff*(cx*cz+sx*sy*sz) + zOff*(cx*sy*sz-sx*cz)
   zPos = object position z(lockTo) + xOff*(-1*sy) + yOff*(sx*cy) + zOff*(cx*cy)
   position camera camera,xPos,yPos,zPos
   set camera to object orientation camera,lockTo
endfunction

And here's a function that works with dbc (thanks Duke Blue Devils/Latch):

+ Code Snippet

FUNCTION weapon_control(object_num,xOffset,yOffset,zOffset)
set object rotation zyx object_num
camAngleX#=camera angle x()
camAngleY#=camera angle y()
camAngleZ#=camera angle z()
camPosX#=camera position x()
camPosY#=camera position y()
camPosZ#=camera position z()
   sx# = sin(camAngleX#) : cx# = cos(camAngleX#)
   sy# = sin(camAngleY#) : cy# = cos(camAngleY#)
   sz# = sin(camAngleZ#) : cz# = cos(camAngleZ#)
   xPos# = camPosX# + xOffset*(cy#*cz#) + yOffset*(sx#*sy#*cz#-cx#*sz#) + zOffset*(cx#*sy#*cz#+sx#*sz#)
   yPos# = camPosY# + xOffset*(cy#*sz#) + yOffset*(cx#*cz#+sx#*sy#*sz#) + zOffset*(cx#*sy#*sz#-sx#*cz#)
   zPos# = camPosZ# + xOffset*(-1*sy#) + yOffset*(sx#*cy#) + zOffset*(cx#*cy#)
position object object_num,xPos#,yPos#,zPos#
set object to camera orientation object_num
set object rotation xyz object_num
ENDFUNCTION

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Juso

21

Years of Service

User Offline

Joined: 23rd Sep 2002

Location: Finland

Posted: 25th Feb 2007 11:04

Link

Fine job,
but what should be changed to lock camera to (moving) object with offsets?

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Milkman

18

Years of Service

User Offline

Joined: 30th Nov 2005

Location: United States

Posted: 26th Feb 2007 21:58

Link

you would need a function such as this:

+ Code Snippet

`locks an object to another object, with offsets
function lockObjectToObject(object as dword,lockTo as dword,xOff as float,yOff as float,zOff as float)
   sx as float : sy as float : sz as float
   cx as float : cy as float : cz as float
   xPos as float : yPos as float : zPos as float
   sx = sin(object angle x(lockTo)) : cx = cos(object angle x(lockTo))
   sy = sin(object angle y(lockTo)) : cy = cos(object angle y(lockTo))
   sz = sin(object angle z(lockTo)) : cz = cos(object angle z(lockTo))
   xPos = object position x(lockTo) + xOff*(cy*cz) + yOff*(sx*sy*cz-cx*sz) + zOff*(cx*sy*cz+sx*sz)
   yPos = object position y(lockTo) + xOff*(cy*sz) + yOff*(cx*cz+sx*sy*sz) + zOff*(cx*sy*sz-sx*cz)
   zPos = object position z(lockTo) + xOff*(-1*sy) + yOff*(sx*cy) + zOff*(cx*cy)
   position object object,xPos,yPos,zPos
   set object to object orientation object,lockTo
endfunction

here is a demonstration of it with dbp code, just copy, paste, and run:

sync on : sync rate 0
autocam off
hide mouse
rate as float

`types
type vector
   x as float = 0.0
   y as float = 0.0
   z as float = 0.0
endtype
type camera
   pos as vector
   rot as vector
endtype

`make camera
cam as camera
position camera 40.0,1.0,40.0
point camera 0,0,0
cam.pos.x=camera position x()
cam.pos.y=camera position y()
cam.pos.z=camera position z()
cam.rot.x=camera angle x()
cam.rot.y=camera angle y()
cam.rot.z=camera angle z()

`make level
level as dword = 1
make matrix level,100.0,100.0,20,20
set matrix level,1,0,1,1,1,1,1
position matrix level,-50.0,0,-50.0

`make gun
gun as dword = 2
make object box gun,0.2,0.2,0.5

`make spinning object
boxObj as dword = 3
make object box boxObj,1.0,1.5,2.5
position object boxObj,35.0,2.0,35.0

do
   `rate scale value
   rate=(10.0/screen fps())

`handle camera
   cam.rot.x=cam.rot.x+mousemovey()*rate*2.0
   cam.rot.y=cam.rot.y+mousemovex()*rate*2.0
   cam.pos.x=cam.pos.x + cos(cam.rot.x)*sin(cam.rot.y)*rate*0.5*(keystate(17)-keystate(31)) + newxvalue(0.0,cam.rot.y-90,rate*0.5*(keystate(30)-keystate(32)))
   cam.pos.y=cam.pos.y - sin(cam.rot.x)*rate*0.5*(keystate(17)-keystate(31))
   cam.pos.z=cam.pos.z + cos(cam.rot.x)*cos(cam.rot.y)*rate*0.5*(keystate(17)-keystate(31)) + newzvalue(0.0,cam.rot.y-90,rate*0.5*(keystate(30)-keystate(32)))
   rotate camera cam.rot.x,cam.rot.y,cam.rot.z
   position camera cam.pos.x,cam.pos.y,cam.pos.z

`lock weapon to screen
   `lockObjectToCamera(gun,0.3,-0.3,1.4)

`rotate box and lock gun to box
   rotate object boxObj,object angle x(boxObj)+2.5*rate,object angle y(boxObj)+2.5*rate,object angle z(boxObj)+2.5*rate
   lockObjectToObject(gun,boxObj,0.5,1.0,1.5)

sync
loop

`locks an object to the screen with offsets
function lockObjectToCamera(object as dword,xOff as float,yOff as float,zOff as float)
   sx as float : sy as float : sz as float
   cx as float : cy as float : cz as float
   xPos as float : yPos as float : zPos as float
   sx = sin(camera angle x()) : cx = cos(camera angle x())
   sy = sin(camera angle y()) : cy = cos(camera angle y())
   sz = sin(camera angle z()) : cz = cos(camera angle z())
   xPos = camera position x() + xOff*(cy*cz) + yOff*(sx*sy*cz-cx*sz) + zOff*(cx*sy*cz+sx*sz)
   yPos = camera position y() + xOff*(cy*sz) + yOff*(cx*cz+sx*sy*sz) + zOff*(cx*sy*sz-sx*cz)
   zPos = camera position z() + xOff*(-1*sy) + yOff*(sx*cy) + zOff*(cx*cy)
   position object object,xPos,yPos,zPos
   set object to camera orientation object
endfunction

`locks an object to another object, with offsets
function lockObjectToObject(object as dword,lockTo as dword,xOff as float,yOff as float,zOff as float)
   sx as float : sy as float : sz as float
   cx as float : cy as float : cz as float
   xPos as float : yPos as float : zPos as float
   sx = sin(object angle x(lockTo)) : cx = cos(object angle x(lockTo))
   sy = sin(object angle y(lockTo)) : cy = cos(object angle y(lockTo))
   sz = sin(object angle z(lockTo)) : cz = cos(object angle z(lockTo))
   xPos = object position x(lockTo) + xOff*(cy*cz) + yOff*(sx*sy*cz-cx*sz) + zOff*(cx*sy*cz+sx*sz)
   yPos = object position y(lockTo) + xOff*(cy*sz) + yOff*(cx*cz+sx*sy*sz) + zOff*(cx*sy*sz-sx*cz)
   zPos = object position z(lockTo) + xOff*(-1*sy) + yOff*(sx*cy) + zOff*(cx*cy)
   position object object,xPos,yPos,zPos
   set object to object orientation object,lockTo
endfunction

+ Code Snippet


sync on : sync rate 0
autocam off
hide mouse
rate as float



`types
type vector
   x as float = 0.0
   y as float = 0.0
   z as float = 0.0
endtype
type camera
   pos as vector
   rot as vector
endtype



`make camera
cam as camera
position camera 40.0,1.0,40.0
point camera 0,0,0
cam.pos.x=camera position x()
cam.pos.y=camera position y()
cam.pos.z=camera position z()
cam.rot.x=camera angle x()
cam.rot.y=camera angle y()
cam.rot.z=camera angle z()



`make level
level as dword = 1
make matrix level,100.0,100.0,20,20
set matrix level,1,0,1,1,1,1,1
position matrix level,-50.0,0,-50.0



`make gun
gun as dword = 2
make object box gun,0.2,0.2,0.5



`make spinning object
boxObj as dword = 3
make object box boxObj,1.0,1.5,2.5
position object boxObj,35.0,2.0,35.0



do
   `rate scale value
   rate=(10.0/screen fps())

   `handle camera
   cam.rot.x=cam.rot.x+mousemovey()*rate*2.0
   cam.rot.y=cam.rot.y+mousemovex()*rate*2.0
   cam.pos.x=cam.pos.x + cos(cam.rot.x)*sin(cam.rot.y)*rate*0.5*(keystate(17)-keystate(31)) + newxvalue(0.0,cam.rot.y-90,rate*0.5*(keystate(30)-keystate(32)))
   cam.pos.y=cam.pos.y - sin(cam.rot.x)*rate*0.5*(keystate(17)-keystate(31))
   cam.pos.z=cam.pos.z + cos(cam.rot.x)*cos(cam.rot.y)*rate*0.5*(keystate(17)-keystate(31)) + newzvalue(0.0,cam.rot.y-90,rate*0.5*(keystate(30)-keystate(32)))
   rotate camera cam.rot.x,cam.rot.y,cam.rot.z
   position camera cam.pos.x,cam.pos.y,cam.pos.z

   `lock weapon to screen
   `lockObjectToCamera(gun,0.3,-0.3,1.4)

   `rotate box and lock gun to box
   rotate object boxObj,object angle x(boxObj)+2.5*rate,object angle y(boxObj)+2.5*rate,object angle z(boxObj)+2.5*rate
   lockObjectToObject(gun,boxObj,0.5,1.0,1.5)

   sync
loop





`locks an object to the screen with offsets
function lockObjectToCamera(object as dword,xOff as float,yOff as float,zOff as float)
   sx as float : sy as float : sz as float
   cx as float : cy as float : cz as float
   xPos as float : yPos as float : zPos as float
   sx = sin(camera angle x()) : cx = cos(camera angle x())
   sy = sin(camera angle y()) : cy = cos(camera angle y())
   sz = sin(camera angle z()) : cz = cos(camera angle z())
   xPos = camera position x() + xOff*(cy*cz) + yOff*(sx*sy*cz-cx*sz) + zOff*(cx*sy*cz+sx*sz)
   yPos = camera position y() + xOff*(cy*sz) + yOff*(cx*cz+sx*sy*sz) + zOff*(cx*sy*sz-sx*cz)
   zPos = camera position z() + xOff*(-1*sy) + yOff*(sx*cy) + zOff*(cx*cy)
   position object object,xPos,yPos,zPos
   set object to camera orientation object
endfunction

`locks an object to another object, with offsets
function lockObjectToObject(object as dword,lockTo as dword,xOff as float,yOff as float,zOff as float)
   sx as float : sy as float : sz as float
   cx as float : cy as float : cz as float
   xPos as float : yPos as float : zPos as float
   sx = sin(object angle x(lockTo)) : cx = cos(object angle x(lockTo))
   sy = sin(object angle y(lockTo)) : cy = cos(object angle y(lockTo))
   sz = sin(object angle z(lockTo)) : cz = cos(object angle z(lockTo))
   xPos = object position x(lockTo) + xOff*(cy*cz) + yOff*(sx*sy*cz-cx*sz) + zOff*(cx*sy*cz+sx*sz)
   yPos = object position y(lockTo) + xOff*(cy*sz) + yOff*(cx*cz+sx*sy*sz) + zOff*(cx*sy*sz-sx*cz)
   zPos = object position z(lockTo) + xOff*(-1*sy) + yOff*(sx*cy) + zOff*(cx*cy)
   position object object,xPos,yPos,zPos
   set object to object orientation object,lockTo
endfunction

so now you have a lockObjectToCamera() function and a lockObjectToObject() function

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Juso

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Joined: 23rd Sep 2002

Location: Finland

Posted: 2nd Mar 2007 16:47 Edited at: 2nd Mar 2007 16:47

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Thanks Milkman, so I made easily LockCameraToObject()

+ Code Snippet

`locks an camera to object, with offsets
function lockCameraToObject(cam as dword,lockTo as dword,xOff as float,yOff as float,zOff as float)
   sx as float : sy as float : sz as float
   cx as float : cy as float : cz as float
   xPos as float : yPos as float : zPos as float
   sx = sin(object angle x(lockTo)) : cx = cos(object angle x(lockTo))
   sy = sin(object angle y(lockTo)) : cy = cos(object angle y(lockTo))
   sz = sin(object angle z(lockTo)) : cz = cos(object angle z(lockTo))
   xPos = object position x(lockTo) + xOff*(cy*cz) + yOff*(sx*sy*cz-cx*sz) + zOff*(cx*sy*cz+sx*sz)
   yPos = object position y(lockTo) + xOff*(cy*sz) + yOff*(cx*cz+sx*sy*sz) + zOff*(cx*sy*sz-sx*cz)
   zPos = object position z(lockTo) + xOff*(-1*sy) + yOff*(sx*cy) + zOff*(cx*cy)
   position camera cam,xPos,yPos,zPos
   set camera to object orientation cam,lockTo
endfunction

and with

+ Code Snippet

   `lock camera to object
   lockCameraToObject(0,boxObj,0.5,1.0,-2.5)

camera spins with cube, very nice

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Latch

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Posted: 7th Mar 2007 10:30 Edited at: 7th Mar 2007 10:31

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@milkman

There was a question on the DBC forum that I was answering that looks like it was based on this algorithm. The problem they were having was with the object not rotating properly with the camera.

I discovered that their function needed to reverse the order of rotation for their object. I had to use the command SET OBJECT ROTATION ZYX. Here's some example code I put together:

sync on
sync rate 60
autocam off

make object box 1,1,1,20

make matrix 1,1000,1000,25,25

do

gosub _move_camera

weapon_control(1,5,0,10)

sync
loop

_move_camera:
   xang#=wrapvalue(xang#+mousemovey())
   yang#=wrapvalue(yang#+mousemovex())

if upkey()=1 then move camera 3
   if downkey()=1 then move camera -3

xrotate camera xang#
   yrotate camera yang#
return

end

FUNCTION weapon_control(object_num,xOffset,yOffset,zOffset)
set object rotation zyx object_num
camAngleX#=camera angle x()
camAngleY#=camera angle y()
camAngleZ#=camera angle z()
camPosX#=camera position x()
camPosY#=camera position y()
camPosZ#=camera position z()
   sx# = sin(camAngleX#) : cx# = cos(camAngleX#)
   sy# = sin(camAngleY#) : cy# = cos(camAngleY#)
   sz# = sin(camAngleZ#) : cz# = cos(camAngleZ#)
   xPos# = camPosX# + xOffset*(cy#*cz#) + yOffset*(sx#*sy#*cz#-cx#*sz#) + zOffset*(cx#*sy#*cz#+sx#*sz#)
   yPos# = camPosY# + xOffset*(cy#*sz#) + yOffset*(cx#*cz#+sx#*sy#*sz#) + zOffset*(cx#*sy#*sz#-sx#*cz#)
   zPos# = camPosZ# + xOffset*(-1*sy#) + yOffset*(sx#*cy#) + zOffset*(cx#*cy#)
position object object_num,xPos#,yPos#,zPos#
set object to camera orientation object_num

ENDFUNCTION

+ Code Snippet

sync on
sync rate 60
autocam off

make object box 1,1,1,20

make matrix 1,1000,1000,25,25

do

   gosub _move_camera

   weapon_control(1,5,0,10)

   sync
loop


_move_camera:
   xang#=wrapvalue(xang#+mousemovey())
   yang#=wrapvalue(yang#+mousemovex())

   if upkey()=1 then move camera 3
   if downkey()=1 then move camera -3

   xrotate camera xang#
   yrotate camera yang#
return


end

FUNCTION weapon_control(object_num,xOffset,yOffset,zOffset)
set object rotation zyx object_num
camAngleX#=camera angle x()
camAngleY#=camera angle y()
camAngleZ#=camera angle z()
camPosX#=camera position x()
camPosY#=camera position y()
camPosZ#=camera position z()
   sx# = sin(camAngleX#) : cx# = cos(camAngleX#)
   sy# = sin(camAngleY#) : cy# = cos(camAngleY#)
   sz# = sin(camAngleZ#) : cz# = cos(camAngleZ#)
   xPos# = camPosX# + xOffset*(cy#*cz#) + yOffset*(sx#*sy#*cz#-cx#*sz#) + zOffset*(cx#*sy#*cz#+sx#*sz#)
   yPos# = camPosY# + xOffset*(cy#*sz#) + yOffset*(cx#*cz#+sx#*sy#*sz#) + zOffset*(cx#*sy#*sz#-sx#*cz#)
   zPos# = camPosZ# + xOffset*(-1*sy#) + yOffset*(sx#*cy#) + zOffset*(cx#*cy#)
position object object_num,xPos#,yPos#,zPos#
set object to camera orientation object_num



ENDFUNCTION

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Milkman

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Posted: 8th Mar 2007 23:13

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@Juso: cool

@Latch: Thanks, I didn't test this with dbc so I wasn't aware of that problem. I've put your dbc code in the first post for anyone who might need it.

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Ianhfar

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Posted: 12th Mar 2007 10:36

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Very usefull fuctions, thans milkman !

IanF

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Latch

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Posted: 12th Mar 2007 11:02

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@Milkman

Duke Blue Devils actually designed the function based on your code. I just was able to get it to work for DBC. So he should get the credit for the function.

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Code Snippets / Mathematically Locking Object to Camera With Offsets