3D Rotation Matrix - GameCreators Forum

Author

Message

pictionaryjr

15

Years of Service

User Offline

Joined: 12th Mar 2009

Location:

Posted: 6th Feb 2011 23:49 Edited at: 7th Feb 2011 19:58

Link

Ok. I worked on a object selection function a long time ago. I thought I had it working and when I tried to use it in a program I'm currently working on. I discovered there were errors in it. I got it to work if the X Y and Z coordinates are at 0. The angles can be whatever, but the moment its x y or z coordinates change, it stops working. I lost the page that I had gotten my information for the rotation matrix from and now all I have found decently is this.

http://en.wikipedia.org/wiki/Rotation_matrix

Here's a knockup program I put the function in. I know its not great.

sync on
sync rate 0
cls
autocam off
make object sphere 100,100
color object 100,rgb(255,255,0)
make object plain 200,1,1
lock object on 200
ghost object on 200
load image "system icons/selection.bmp",200
texture object 200,200
for o=1 to 50
   make object sphere o,10
   position object o,rnd(1000)-500,rnd(1000)-500,rnd(1000)-500
   set object rotation zyx o
   setupobjectdbc(o,1,0)
next o
nmaxspin#=-3.0 : pmaxspin#=3.0
do
mx=mousex() : my=mousey()
if keystate(17)=1 then position camera camera position x(),camera position y()+.001,camera position z()
if keystate(31)=1 then position camera camera position x(),camera position y()-.001,camera position z()
if keystate(30)=1 then position camera camera position x()-.001,camera position y(),camera position z()
if keystate(32)=1 then position camera camera position x()+.001,camera position y(),camera position z()

if clicked=0
   if mouseclick()=1
      mx1=mx
      my1=my
      clicked=1
   endif
if mx=0 or mx=639
   if mx=0
      if xturn#>nmaxspin# then dec xturn#,.5
   endif
   if mx=639
      if xturn#<pmaxspin# then inc xturn#,.5
   endif
   yrotate camera wrapvalue(camera angle y()+xturn#)
else
   xturn#=0
endif
if my=0 or my=479
   if my=0
      if camera angle x()<315 and camera angle x()>310
         yturn#=0
      else
         if yturn#>nmaxspin# then dec yturn#,.5
      endif
   endif
   if my=479
      if camera angle x()>45 and camera angle x()<50
         yturn#=0
      else
         if yturn#<pmaxspin# then inc yturn#,.5
      endif
   endif
   xrotate camera wrapvalue(camera angle x()+yturn#)
else
   yturn#=0
endif
else
   if mouseclick()=0
      mx2=mx
      my2=my
      clicked=0
      if mx1=mx2 and my1=my2
         collide=pickobject(mx1,my1,1000,1,1,0)
         if collide>0
            for o=1 to 50
               if o=collide
                  color object o,rgb(255,0,0)
               else
                  color object o,rgb(255,255,255)
               endif
            next o
         else
            for o=1 to 50
               color object o,rgb(255,255,255)
            next o
         endif
      else
         if mx1>mx2
            if my1>my2
               for o=1 to 50
                  if object screen x(o)<=mx1 and object screen x(o)>=mx2 and object screen y(o)<=my1 and object screen y(o)>=my2
                     color object o,rgb(255,0,0)
                  else
                     color object o,rgb(255,255,255)
                  endif
               next o
            else
               for o=1 to 50
                  if object screen x(o)<=mx1 and object screen x(o)>=mx2 and object screen y(o)<=my2 and object screen y(o)>=my1
                     color object o,rgb(255,0,0)
                  else
                     color object o,rgb(255,255,255)
                  endif
               next o
            endif
         else
            if my1>my2
               for o=1 to 50
                  if object screen x(o)<=mx2 and object screen x(o)>=mx1 and object screen y(o)<=my1 and object screen y(o)>=my2
                     color object o,rgb(255,0,0)
                  else
                     color object o,rgb(255,255,255)
                  endif
               next o
            else
               for o=1 to 50
                  if object screen x(o)<=mx2 and object screen x(o)>=mx1 and object screen y(o)<=my2 and object screen y(o)>=my1
                     color object o,rgb(255,0,0)
                  else
                     color object o,rgb(255,255,255)
                  endif
               next o
            endif
         endif
      endif
   endif
   line mx1,my1,mx1,my
   line mx1,my1,mx,my1
   line mx,my1,mx,my
   line mx1,my,mx,my
   `This section is just getting it to work with a 3d object instead of a 2d selection box
   remstart
   if mx>mx1
      if 480-my>480-my1
         scale object 200,(mx-mx1)*100,((480-my)-(480-my1))*100,100
         position object 200,(mx1-320)+((mx-mx1)/2),((480-my1)-240)+(((480-my)-(480-my1))/2),400
      else
         scale object 200,(mx-mx1)*100,((480-my1)-(480-my))*100,100
         position object 200,(mx1-320)+((mx-mx1)/2),((480-my)-240)+(((480-my1)-(480-my))/2),400
      endif
   else
      if 480-my>480-my1
         scale object 200,(mx-mx1)*100,((480-my)-(480-my1))*100,100
         position object 200,(mx-320)+((mx1-mx)/2),((480-my1)-240)+(((480-my)-(480-my1))/2),400
      else
         scale object 200,(mx-mx1)*100,((480-my1)-(480-my))*100,100
         position object 200,(mx-320)+((mx1-mx)/2),((480-my)-240)+(((480-my1)-(480-my))/2),400
      endif
   endif
   remend
endif
timesync(10)
loop

function pickobject(mx,my,distance,num,flag,exclude)
   cax#=camera angle x()
   cay#=camera angle y()
   cx#=camera position x()
   cy#=camera position y()
   cz#=camera position z()
   fov#=62
   my=screen height()-my
   xdist#=(screen width()/2)/tan(fov#/2)
   ydist#=(screen height()/2)/tan(fov#/2)
   xwidth#=(mx-(screen width()/2))/1.15
   ywidth#=(my-(screen height()/2))/1.4
   yang#=atanfull(ydist#,ywidth#)
   ypos#=((cy#+((ydist#+distance)/tan(yang#)))*cos(cax#))+((cz#+distance)*(-1*sin(cax#)))
   zpos#=((cy#+((ydist#+distance)/tan(yang#)))*sin(cax#))+((cz#+distance)*cos(cax#))
   xang#=atanfull(xdist#,xwidth#)
   xpos#=((cx#+((xdist#+distance)/tan(xang#)))*cos(cay#))+(zpos#*sin(cay#))
   zpos#=((cx#+((xdist#+distance)/tan(xang#)))*(-1*sin(cay#)))+(zpos#*cos(cay#))
   object=intersectObjectDBC(num,flag,cx#,cy#,cz#,xpos#,ypos#,zpos#,exclude)
endfunction object

function timesync(time)
a=timer()
if a-b>=time
   b=timer()
   sync
endif
endfunction

`~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
`=================================================================================================================
`Sparky's Collision Commands
`=================================================================================================================
`~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
remstart
Commands:
    setupObjectDBC(<objNum>,<GroupNum>,<Collision Type>)
        -objNum:        the object you want to setup
        -groupNum:      the group that you want this object to belong to
                        if you're not using groups then this value is ignored
        -collisionType: sets the type of collision to use with this object
                        0 - polygon collision, will check with every polygon in the object
                  1 - sphere collision, will create an ellipse around the object and check collisions with that
                  2 - box collision, will create a box around the object for collisions.

Mesh 255, memblock 255 and memblock 254 must not be in use.
      This command sets up an object for collision, need only be called once for each object.
      this command will also work when the object has been scaled before calling it
      but any further scaling of the object will not be updated in the collision (not even with update object)

setupComplexObjectDBC(<objNum>,<GroupNum>,<FacesPerNode>)
        -objNum:        the object you want to setup
        -groupNum:      the group that you want this object to belong to
                        if you're not using groups then this value is ignored
        -FacesPerNode:  sets the maximum number of faces per tree node, usually the smaller this value the better the performance
                        but I'll give you the option of changing this value to see if another value works better for your object.
                        If you are unsure of this option just use a value of 2.

Mesh 255, memblock 255 and memblock 254 must not be in use.
      almost exactly the same as setup object except this command will setup optimized polygon collision on a
      complex (high poly) object so that you get much better performance for these types of object.
      realistically you probably won't notice any difference between this and normal polygon collision
      for objects of less than 30-40 polys, but higher polycounts definately benifit from higher performance.
      You can think of it as splitting the object up into little bits, of size specified by facesPerNode,
      and only checking collision with sections near the ray, therefore cutting out alot of polygons.

updateObjectDBC(<objNum>)
       -objNum:       the object you want to update

memblock 255 must not be in use.
       Will update the collision data with the object's new position and rotation.
       Should be called for any object that is changed before a collision
         - for example if you want to move an object and check collision, move agian
            and check collision again, then update should be called after both moves.
            however, if you move an object, move it again, then check collision, you only
            need to call the update method after the second move.

intersectObjectDBC(<obj/groupNum>,<GroupFlag>,<oldx>,<oldy>,<oldz>,<x>,<y>,<z>,<excludeObj>)
         -obj/groupNum:  the object or group you want to check for collision use 0 for all objects or groups
         -GroupFlag:      set this to 0 if you want to work with objects or 1 if you want to work with groups
         -oldx...z:      the start and end points of the ray to check.
         -excludeObj:   an object to exclude from the collision check (excludes a single object from both
                     object and group checks)

returns: if checking groups or all objects then the object number collided with is returned
                if checking a specific object then a 1 is returned if a collision occured.
                in either case, returns 0 if no collision occured.

will check if the ray starting at oldx#,oldy#,oldz# and ending at
         x#,y#,z# collides with the specified object or group (obj=0 for all).
         does not collide with backfaces, will return the number of the object
         hit first, or 0 for no collision.

setObjectCollisionOffDBC(<objNum>)
          -objNum:      the object you want to turn off collision.

turns off collision with this object in both object and group collisions.

setObjectCollisionOnDBC(<objNum>)
          -objNum:      the object you want to turn on collision.

turns on collision with this object in both object and group collisions.
          the default setting from setup object is ON.

collisionStatusDBC(<objNum>)
         -objNum:      the object you want to know the status of.

returns the current collision setting for this object, 1 for on, 0 for off.

getStaticCollisionX()
          returns the x co-ordinate of actual collision point
   getStaticCollisionY()
          returns the y co-ordinate of actual collision point
   getStaticCollisionZ()
          returns the z co-ordinate of actual collision point

getCollisionNormalX()
          returns the x component of the collision normal
   getCollisionNormalY()
          returns the y component of the collision normal
   getCollisionNormalZ()
          returns the z component of the collision normal

getCollisionBounceX()
          returns the x component of the bounce vector
   getCollisionBounceY()
          returns the y component of the bounce vector
   getCollisionBounceZ()
          returns the z component of the bounce vector

The bounce vector is the vector (like the normal) representing the direction
   the ray would end up if it bounced off the collision point (like a bullet ricohet)

remend
function LoadSparkys()
   load dll "DBCollision.dll", 1
endfunction

function setupObjectDBC(objNum,groupNum,objectType)
    commonSetup(objNum)

vertData = get memblock ptr(3)
    objectData = get memblock ptr(2)
    call dll 1,"setupObject",objNum,groupNum,objectType,vertData,objectData

delete memblock 3
endfunction

function setupComplexObjectDBC(objNum,groupNum,facesPerNode)
    commonSetup(objNum)

vertData = get memblock ptr(3)
    objectData = get memblock ptr(2)
    call dll 1,"setupComplexObject",objNum,groupNum,facesPerNode,vertData,objectData

delete memblock 3
endfunction

function commonSetup(objNum)
    if dll exist(1)=0 then load dll "DBCcollision.dll",1
    if memblock exist(2)=0 then make memblock 2,24

x#=object position x(objNum)
    y#=object position y(objNum)
    z#=object position z(objNum)
    angx#=object angle x(objNum)
    angy#=object angle y(objNum)
    angz#=object angle z(objNum)

write memblock float 2,0,x#
    write memblock float 2,4,y#
    write memblock float 2,8,z#
    write memblock float 2,12,angx#
    write memblock float 2,16,angy#
    write memblock float 2,20,angz#

position object objNum,0,0,0
    rotate object objNum,0,0,0
    make mesh from object 2,objNum
    make memblock from mesh 3,2
    delete mesh 2
    position object objNum,x#,y#,z#
    rotate object objNum,angx#,angy#,angz#
endfunction

function updateObjectDBC(objNum)
    if memblock exist(2)=0 then make memblock 2,24

write memblock float 2,0,object position x(objNum)
    write memblock float 2,4,object position y(objNum)
    write memblock float 2,8,object position z(objNum)
    write memblock float 2,12,object angle x(objNum)
    write memblock float 2,16,object angle y(objNum)
    write memblock float 2,20,object angle z(objNum)

objectData = get memblock ptr(2)

call dll 1,"updateObject",objNum,objectData
endfunction

function intersectObjectDBC(objNum,groupFlag,oldx#,oldy#,oldz#,x#,y#,z#,excludeObj)
    collide=call dll(1,"intersectObject",objNum,groupFlag,oldx#,oldy#,oldz#,x#,y#,z#,excludeObj)
endfunction collide

function setObjectCollisionOnDBC(objNum)
    call dll 1,"set_object_collision_on",objNum
endfunction

function setObjectCollisionOffDBC(objNum)
    call dll 1,"set_object_collision_off",objNum
endfunction

function collisionStatusDBC(objNum)
    result=call dll(1,"collisionstatus",objNum)
endfunction result

function getStaticCollisionX()
    result#=call dll(1,"getStaticCollisionX")
endfunction result#

function getStaticCollisionY()
    result#=call dll(1,"getStaticCollisionY")
endfunction result#

function getStaticCollisionZ()
    result#=call dll(1,"getStaticCollisionZ")
endfunction result#

function getCollisionNormalX()
    result#=call dll(1,"getCollisionNormalX")
endfunction result#

function getCollisionNormalY()
    result#=call dll(1,"getCollisionNormalY")
endfunction result#

function getCollisionNormalZ()
    result#=call dll(1,"getCollisionNormalZ")
endfunction result#

+ Code Snippet

sync on
sync rate 0
cls
autocam off
make object sphere 100,100
color object 100,rgb(255,255,0)
make object plain 200,1,1
lock object on 200
ghost object on 200
load image "system icons/selection.bmp",200
texture object 200,200
for o=1 to 50
   make object sphere o,10
   position object o,rnd(1000)-500,rnd(1000)-500,rnd(1000)-500
   set object rotation zyx o
   setupobjectdbc(o,1,0)
next o
nmaxspin#=-3.0 : pmaxspin#=3.0
do
mx=mousex() : my=mousey()
if keystate(17)=1 then position camera camera position x(),camera position y()+.001,camera position z()
if keystate(31)=1 then position camera camera position x(),camera position y()-.001,camera position z()
if keystate(30)=1 then position camera camera position x()-.001,camera position y(),camera position z()
if keystate(32)=1 then position camera camera position x()+.001,camera position y(),camera position z()

if clicked=0
   if mouseclick()=1
      mx1=mx
      my1=my
      clicked=1
   endif
if mx=0 or mx=639
   if mx=0
      if xturn#>nmaxspin# then dec xturn#,.5
   endif
   if mx=639
      if xturn#<pmaxspin# then inc xturn#,.5
   endif
   yrotate camera wrapvalue(camera angle y()+xturn#)
else
   xturn#=0
endif
if my=0 or my=479
   if my=0
      if camera angle x()<315 and camera angle x()>310
         yturn#=0
      else
         if yturn#>nmaxspin# then dec yturn#,.5
      endif
   endif
   if my=479
      if camera angle x()>45 and camera angle x()<50
         yturn#=0
      else
         if yturn#<pmaxspin# then inc yturn#,.5
      endif
   endif
   xrotate camera wrapvalue(camera angle x()+yturn#)
else
   yturn#=0
endif
else
   if mouseclick()=0
      mx2=mx
      my2=my
      clicked=0
      if mx1=mx2 and my1=my2
         collide=pickobject(mx1,my1,1000,1,1,0)
         if collide>0
            for o=1 to 50
               if o=collide
                  color object o,rgb(255,0,0)
               else
                  color object o,rgb(255,255,255)
               endif
            next o
         else
            for o=1 to 50
               color object o,rgb(255,255,255)
            next o
         endif
      else
         if mx1>mx2
            if my1>my2
               for o=1 to 50
                  if object screen x(o)<=mx1 and object screen x(o)>=mx2 and object screen y(o)<=my1 and object screen y(o)>=my2
                     color object o,rgb(255,0,0)
                  else
                     color object o,rgb(255,255,255)
                  endif
               next o
            else
               for o=1 to 50
                  if object screen x(o)<=mx1 and object screen x(o)>=mx2 and object screen y(o)<=my2 and object screen y(o)>=my1
                     color object o,rgb(255,0,0)
                  else
                     color object o,rgb(255,255,255)
                  endif
               next o
            endif
         else
            if my1>my2
               for o=1 to 50
                  if object screen x(o)<=mx2 and object screen x(o)>=mx1 and object screen y(o)<=my1 and object screen y(o)>=my2
                     color object o,rgb(255,0,0)
                  else
                     color object o,rgb(255,255,255)
                  endif
               next o
            else
               for o=1 to 50
                  if object screen x(o)<=mx2 and object screen x(o)>=mx1 and object screen y(o)<=my2 and object screen y(o)>=my1
                     color object o,rgb(255,0,0)
                  else
                     color object o,rgb(255,255,255)
                  endif
               next o
            endif
         endif
      endif
   endif
   line mx1,my1,mx1,my
   line mx1,my1,mx,my1
   line mx,my1,mx,my
   line mx1,my,mx,my
   `This section is just getting it to work with a 3d object instead of a 2d selection box
   remstart
   if mx>mx1
      if 480-my>480-my1
         scale object 200,(mx-mx1)*100,((480-my)-(480-my1))*100,100
         position object 200,(mx1-320)+((mx-mx1)/2),((480-my1)-240)+(((480-my)-(480-my1))/2),400
      else
         scale object 200,(mx-mx1)*100,((480-my1)-(480-my))*100,100
         position object 200,(mx1-320)+((mx-mx1)/2),((480-my)-240)+(((480-my1)-(480-my))/2),400
      endif
   else
      if 480-my>480-my1
         scale object 200,(mx-mx1)*100,((480-my)-(480-my1))*100,100
         position object 200,(mx-320)+((mx1-mx)/2),((480-my1)-240)+(((480-my)-(480-my1))/2),400
      else
         scale object 200,(mx-mx1)*100,((480-my1)-(480-my))*100,100
         position object 200,(mx-320)+((mx1-mx)/2),((480-my)-240)+(((480-my1)-(480-my))/2),400
      endif
   endif
   remend
endif
timesync(10)
loop

function pickobject(mx,my,distance,num,flag,exclude)
   cax#=camera angle x()
   cay#=camera angle y()
   cx#=camera position x()
   cy#=camera position y()
   cz#=camera position z()
   fov#=62
   my=screen height()-my
   xdist#=(screen width()/2)/tan(fov#/2)
   ydist#=(screen height()/2)/tan(fov#/2)
   xwidth#=(mx-(screen width()/2))/1.15
   ywidth#=(my-(screen height()/2))/1.4
   yang#=atanfull(ydist#,ywidth#)
   ypos#=((cy#+((ydist#+distance)/tan(yang#)))*cos(cax#))+((cz#+distance)*(-1*sin(cax#)))
   zpos#=((cy#+((ydist#+distance)/tan(yang#)))*sin(cax#))+((cz#+distance)*cos(cax#))
   xang#=atanfull(xdist#,xwidth#)
   xpos#=((cx#+((xdist#+distance)/tan(xang#)))*cos(cay#))+(zpos#*sin(cay#))
   zpos#=((cx#+((xdist#+distance)/tan(xang#)))*(-1*sin(cay#)))+(zpos#*cos(cay#))
   object=intersectObjectDBC(num,flag,cx#,cy#,cz#,xpos#,ypos#,zpos#,exclude)
endfunction object

function timesync(time)
a=timer()
if a-b>=time
   b=timer()
   sync
endif
endfunction

`~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
`=================================================================================================================
`Sparky's Collision Commands
`=================================================================================================================
`~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
remstart
Commands:
    setupObjectDBC(<objNum>,<GroupNum>,<Collision Type>)
        -objNum:        the object you want to setup
        -groupNum:      the group that you want this object to belong to
                        if you're not using groups then this value is ignored
        -collisionType: sets the type of collision to use with this object
                        0 - polygon collision, will check with every polygon in the object
                  1 - sphere collision, will create an ellipse around the object and check collisions with that
                  2 - box collision, will create a box around the object for collisions.

      Mesh 255, memblock 255 and memblock 254 must not be in use.
      This command sets up an object for collision, need only be called once for each object.
      this command will also work when the object has been scaled before calling it
      but any further scaling of the object will not be updated in the collision (not even with update object)

   setupComplexObjectDBC(<objNum>,<GroupNum>,<FacesPerNode>)
        -objNum:        the object you want to setup
        -groupNum:      the group that you want this object to belong to
                        if you're not using groups then this value is ignored
        -FacesPerNode:  sets the maximum number of faces per tree node, usually the smaller this value the better the performance
                        but I'll give you the option of changing this value to see if another value works better for your object.
                        If you are unsure of this option just use a value of 2.

      Mesh 255, memblock 255 and memblock 254 must not be in use.
      almost exactly the same as setup object except this command will setup optimized polygon collision on a
      complex (high poly) object so that you get much better performance for these types of object.
      realistically you probably won't notice any difference between this and normal polygon collision
      for objects of less than 30-40 polys, but higher polycounts definately benifit from higher performance.
      You can think of it as splitting the object up into little bits, of size specified by facesPerNode,
      and only checking collision with sections near the ray, therefore cutting out alot of polygons.

   updateObjectDBC(<objNum>)
       -objNum:       the object you want to update

       memblock 255 must not be in use.
       Will update the collision data with the object's new position and rotation.
       Should be called for any object that is changed before a collision
         - for example if you want to move an object and check collision, move agian
            and check collision again, then update should be called after both moves.
            however, if you move an object, move it again, then check collision, you only
            need to call the update method after the second move.

   intersectObjectDBC(<obj/groupNum>,<GroupFlag>,<oldx>,<oldy>,<oldz>,<x>,<y>,<z>,<excludeObj>)
         -obj/groupNum:  the object or group you want to check for collision use 0 for all objects or groups
         -GroupFlag:      set this to 0 if you want to work with objects or 1 if you want to work with groups
         -oldx...z:      the start and end points of the ray to check.
         -excludeObj:   an object to exclude from the collision check (excludes a single object from both
                     object and group checks)

         returns: if checking groups or all objects then the object number collided with is returned
                if checking a specific object then a 1 is returned if a collision occured.
                in either case, returns 0 if no collision occured.

         will check if the ray starting at oldx#,oldy#,oldz# and ending at
         x#,y#,z# collides with the specified object or group (obj=0 for all).
         does not collide with backfaces, will return the number of the object
         hit first, or 0 for no collision.

   setObjectCollisionOffDBC(<objNum>)
          -objNum:      the object you want to turn off collision.

          turns off collision with this object in both object and group collisions.

   setObjectCollisionOnDBC(<objNum>)
          -objNum:      the object you want to turn on collision.

          turns on collision with this object in both object and group collisions.
          the default setting from setup object is ON.

   collisionStatusDBC(<objNum>)
         -objNum:      the object you want to know the status of.

         returns the current collision setting for this object, 1 for on, 0 for off.

   getStaticCollisionX()
          returns the x co-ordinate of actual collision point
   getStaticCollisionY()
          returns the y co-ordinate of actual collision point
   getStaticCollisionZ()
          returns the z co-ordinate of actual collision point

   getCollisionNormalX()
          returns the x component of the collision normal
   getCollisionNormalY()
          returns the y component of the collision normal
   getCollisionNormalZ()
          returns the z component of the collision normal

   getCollisionBounceX()
          returns the x component of the bounce vector
   getCollisionBounceY()
          returns the y component of the bounce vector
   getCollisionBounceZ()
          returns the z component of the bounce vector

   The bounce vector is the vector (like the normal) representing the direction
   the ray would end up if it bounced off the collision point (like a bullet ricohet)

remend
function LoadSparkys()
   load dll "DBCollision.dll", 1
endfunction

function setupObjectDBC(objNum,groupNum,objectType)
    commonSetup(objNum)

    vertData = get memblock ptr(3)
    objectData = get memblock ptr(2)
    call dll 1,"setupObject",objNum,groupNum,objectType,vertData,objectData

    delete memblock 3
endfunction

function setupComplexObjectDBC(objNum,groupNum,facesPerNode)
    commonSetup(objNum)

    vertData = get memblock ptr(3)
    objectData = get memblock ptr(2)
    call dll 1,"setupComplexObject",objNum,groupNum,facesPerNode,vertData,objectData

    delete memblock 3
endfunction

function commonSetup(objNum)
    if dll exist(1)=0 then load dll "DBCcollision.dll",1
    if memblock exist(2)=0 then make memblock 2,24

    x#=object position x(objNum)
    y#=object position y(objNum)
    z#=object position z(objNum)
    angx#=object angle x(objNum)
    angy#=object angle y(objNum)
    angz#=object angle z(objNum)

    write memblock float 2,0,x#
    write memblock float 2,4,y#
    write memblock float 2,8,z#
    write memblock float 2,12,angx#
    write memblock float 2,16,angy#
    write memblock float 2,20,angz#

    position object objNum,0,0,0
    rotate object objNum,0,0,0
    make mesh from object 2,objNum
    make memblock from mesh 3,2
    delete mesh 2
    position object objNum,x#,y#,z#
    rotate object objNum,angx#,angy#,angz#
endfunction

function updateObjectDBC(objNum)
    if memblock exist(2)=0 then make memblock 2,24

    write memblock float 2,0,object position x(objNum)
    write memblock float 2,4,object position y(objNum)
    write memblock float 2,8,object position z(objNum)
    write memblock float 2,12,object angle x(objNum)
    write memblock float 2,16,object angle y(objNum)
    write memblock float 2,20,object angle z(objNum)

    objectData = get memblock ptr(2)

    call dll 1,"updateObject",objNum,objectData
endfunction

function intersectObjectDBC(objNum,groupFlag,oldx#,oldy#,oldz#,x#,y#,z#,excludeObj)
    collide=call dll(1,"intersectObject",objNum,groupFlag,oldx#,oldy#,oldz#,x#,y#,z#,excludeObj)
endfunction collide

function setObjectCollisionOnDBC(objNum)
    call dll 1,"set_object_collision_on",objNum
endfunction

function setObjectCollisionOffDBC(objNum)
    call dll 1,"set_object_collision_off",objNum
endfunction

function collisionStatusDBC(objNum)
    result=call dll(1,"collisionstatus",objNum)
endfunction result

function getStaticCollisionX()
    result#=call dll(1,"getStaticCollisionX")
endfunction result#

function getStaticCollisionY()
    result#=call dll(1,"getStaticCollisionY")
endfunction result#

function getStaticCollisionZ()
    result#=call dll(1,"getStaticCollisionZ")
endfunction result#

function getCollisionNormalX()
    result#=call dll(1,"getCollisionNormalX")
endfunction result#

function getCollisionNormalY()
    result#=call dll(1,"getCollisionNormalY")
endfunction result#

function getCollisionNormalZ()
    result#=call dll(1,"getCollisionNormalZ")
endfunction result#

Here's the function. Please help. the section I'm concerned with is the xpos#=code : ypos#=code : zpos#=code

+ Code Snippet

function pickobject(mx,my,distance,num,flag,exclude)
   cax#=camera angle x()
   cay#=camera angle y()
   cx#=camera position x()
   cy#=camera position y()
   cz#=camera position z()
   fov#=62
   my=screen height()-my
   xdist#=(screen width()/2)/tan(fov#/2)
   ydist#=(screen height()/2)/tan(fov#/2)
   xwidth#=(mx-(screen width()/2))/1.15
   ywidth#=(my-(screen height()/2))/1.4
   yang#=atanfull(ydist#,ywidth#)
   ypos#=((cy#+((ydist#+distance)/tan(yang#)))*cos(cax#))+((cz#+distance)*(-1*sin(cax#)))
   zpos#=((cy#+((ydist#+distance)/tan(yang#)))*sin(cax#))+((cz#+distance)*cos(cax#))
   xang#=atanfull(xdist#,xwidth#)
   xpos#=((cx#+((xdist#+distance)/tan(xang#)))*cos(cay#))+(zpos#*sin(cay#))
   zpos#=((cx#+((xdist#+distance)/tan(xang#)))*(-1*sin(cay#)))+(zpos#*cos(cay#))
   object=intersectObjectDBC(num,flag,cx#,cy#,cz#,xpos#,ypos#,zpos#,exclude)
endfunction object

EDIT:
Nvm, got it. It was a real simple solution although i'm not sure how it worked.

+ Code Snippet

function pickobject(mx,my,distance,num,flag,exclude)
   cax#=camera angle x()
   cay#=camera angle y()
   cx#=camera position x()
   cy#=camera position y()
   cz#=camera position z()
   fov#=62
   my=screen height()-my
   xdist#=(screen width()/2)/tan(fov#/2)
   ydist#=(screen height()/2)/tan(fov#/2)
   xwidth#=(mx-(screen width()/2))/1.15
   ywidth#=(my-(screen height()/2))/1.4
   yang#=atanfull(ydist#,ywidth#)
   ypos#=(((ydist#+distance)/tan(yang#))*cos(cax#))+(distance*(-1*sin(cax#)))
   zpos#=(((ydist#+distance)/tan(yang#))*sin(cax#))+(distance*cos(cax#))
   xang#=atanfull(xdist#,xwidth#)
   xpos#=(((xdist#+distance)/tan(xang#))*cos(cay#))+(zpos#*sin(cay#))
   zpos#=(((xdist#+distance)/tan(xang#))*(-1*sin(cay#)))+(zpos#*cos(cay#))
   xpos#=xpos#+cx#
   ypos#=ypos#+cy#
   zpos#=zpos#+cz#
   object=intersectObjectDBC(num,flag,cx#,cy#,cz#,xpos#,ypos#,zpos#,exclude)
endfunction object

TEAM REQUEST FORUMS

Back to top

Profile PM Email

29 games

18

Years of Service

User Offline

Joined: 23rd Nov 2005

Location: not entirely sure

Posted: 7th Feb 2011 23:43 Edited at: 7th Feb 2011 23:48

Link

Hi Pictionary, you seem to have prempted my response but I'll post this anyway.

I've been having a look at your pick object function (pretty much all I've done since I got home from work) and to be honest I don't understand the maths.

I even went through your old post http://forum.thegamecreators.com/?m=forum_view&t=171199&b=10 where other people went through it all.

I still don't understand the maths.

However, I tracked down this post http://forum.thegamecreators.com/?m=forum_view&t=154696&b=10 where someone came up with an object picker using the in-built DBC collision commands.

I lifted the code out, with a couple of minor modifications that I've highlighted (mainly so it will work as you originally intended) and it works perfectly (he says with a certain amount of trepidation).

sync rate 65
sync on
autocam off

make matrix 1, 1000,1000,10,10

make object cube 1, 100
color object 1, rgb(250,0,0)
setupObjectDBC(1,0,0)
position object 1, 0,800,500
updateObjectDBC(1)

make object cone 2, 100
color object 2, rgb(0,250,0)
setupObjectDBC(2,0,0)
position object 2, 500,50,1000
updateObjectDBC(2)

make object sphere 3, 100
color object 3, rgb(0,250,0)
setupObjectDBC(3,0,0)
position object 3, 800, 100, 200
updateObjectDBC(3)

do

`color all objects green
   for i = 1 to 3
      color object i, rgb(0,250,0)
   next i

`controls for panning and tilting camera
   if leftkey() = 1 then turn camera left 1
   if rightkey() = 1 then turn camera right 1
   if upkey() = 1 then pitch camera up 1
   if downkey() = 1 then pitch camera down 1

`call the pick object function
   obj = pickobject(mousex(),mousey(),3000,0,0,0)

`color any oject picked red
   if obj <> 0 then color object obj, rgb(250,0,0)

`position camera (change this to another position and you'll see that the function still works).
   position camera 300, 200, -500

set cursor 0,0
   print "use arrow keys to pan and tilt camera"
   print "objects will turn red when the mouse cursor it over them"

sync

loop

end

function pickobject(mx,my,distance,num,flag,exclude)

`most of this has been taken from http://forum.thegamecreators.com/?m=forum_view&t=154696&b=10
   `the 3D picker code snippet a couple of posts from the top

dim sx#(2)  :`<<<<<<<<<<<<<<< originally global arrays
   dim sy#(2)  :`<<<<<<<<<<<<<<< originally global arrays
   dim sz#(2)  :`<<<<<<<<<<<<<<< originally global arrays

`set distance of nearest point
   dist#=1
   for i = 1 to 2
      px#=(((dist#*.8)+.8)*2)/screen width()
      py#=(((dist#*.6)+.6)*2)/screen height()

CAX#=camera angle x()
      CAY#=camera angle y()
      CAZ#=camera angle z()

CPX#=camera position x()
      CPY#=camera position y()
      CPZ#=camera position z()

rem mx#=mousex()    :`<<<<<<<<<<<<<<< original code
      rem my#=mousey()    :`<<<<<<<<<<<<<<< original code
      mx# = mx         :`<<<<<<<<<<<<<<< new so your function will work as you intended
      my# = my         :`<<<<<<<<<<<<<<< new so your function will work as you intended
      X1#=(mx#*px#)-((dist#*.8)+.8)
      Y1#=((dist#*.6)+.6)-(my#*py#)
      Z1#=dist#+1

cosCAX#=cos(CAX#)
      cosCAY#=cos(CAY#)
      cosCAZ#=cos(CAZ#)
      sinCAX#=sin(CAX#)
      sinCAY#=sin(CAY#)
      sinCAZ#=sin(CAZ#)

X2#=X1#
      Y2#=cosCAX#*Y1#-sinCAX#*Z1#
      Z2#=SinCAX#*Y1#+CosCAX#*Z1#
      `Yrotate Vector
      X3#=CosCAY#*X2#+SinCAY#*Z2#
      Y3#=Y2#
      Z3#=CosCAY#*Z2#-SinCAY#*X2#
      `Zrotate Vector
      X4#=CosCAZ#*X3#-SinCAZ#*Y3#
      Y4#=SinCAZ#*X3#+CosCAZ#*Y3#
      Z4#=Z3#

sx#(i)=CPX#+X4#
      sy#(i)=CPY#+Y4#
      sz#(i)=CPZ#+Z4#

`set distance of furthest point
      dist#=distance

next i

object = intersectObjectDBC(num,flag,sx#(1),sy#(1),sz#(1),sx#(2),sy#(2),sz#(2),exclude)
endfunction object

function setupObjectDBC(objNum,groupNum,objectType)
    commonSetup(objNum)

vertData = get memblock ptr(254)
    objectData = get memblock ptr(255)
    call dll 1,"setupObject",objNum,groupNum,objectType,vertData,objectData

delete memblock 254
endfunction

function updateObjectDBC(objNum)
    if memblock exist(255)=0 then make memblock 255,24

write memblock float 255,0,object position x(objNum)
    write memblock float 255,4,object position y(objNum)
    write memblock float 255,8,object position z(objNum)
    write memblock float 255,12,object angle x(objNum)
    write memblock float 255,16,object angle y(objNum)
    write memblock float 255,20,object angle z(objNum)

objectData = get memblock ptr(255)

call dll 1,"updateObject",objNum,objectData
endfunction

function commonSetup(objNum)
    if dll exist(1)=0 then load dll "DBCcollision.dll",1
    if memblock exist(255)=0 then make memblock 255,24

x#=object position x(objNum)
    y#=object position y(objNum)
    z#=object position z(objNum)
    angx#=object angle x(objNum)
    angy#=object angle y(objNum)
    angz#=object angle z(objNum)

write memblock float 255,0,x#
    write memblock float 255,4,y#
    write memblock float 255,8,z#
    write memblock float 255,12,angx#
    write memblock float 255,16,angy#
    write memblock float 255,20,angz#

position object objNum,0,0,0
    rotate object objNum,0,0,0
    make mesh from object 255,objNum
    make memblock from mesh 254,255
    delete mesh 255
    position object objNum,x#,y#,z#
    rotate object objNum,angx#,angy#,angz#
endfunction

function intersectObjectDBC(objNum,groupFlag,oldx#,oldy#,oldz#,x#,y#,z#,excludeObj)
    collide=call dll(1,"intersectObject",objNum,groupFlag,oldx#,oldy#,oldz#,x#,y#,z#,excludeObj)
endfunction collide

+ Code Snippet

sync rate 65
sync on
autocam off


make matrix 1, 1000,1000,10,10


make object cube 1, 100
color object 1, rgb(250,0,0)
setupObjectDBC(1,0,0)
position object 1, 0,800,500
updateObjectDBC(1)


make object cone 2, 100
color object 2, rgb(0,250,0)
setupObjectDBC(2,0,0)
position object 2, 500,50,1000
updateObjectDBC(2)

make object sphere 3, 100
color object 3, rgb(0,250,0)
setupObjectDBC(3,0,0)
position object 3, 800, 100, 200
updateObjectDBC(3)


do

   `color all objects green
   for i = 1 to 3
      color object i, rgb(0,250,0)
   next i

   `controls for panning and tilting camera
   if leftkey() = 1 then turn camera left 1
   if rightkey() = 1 then turn camera right 1
   if upkey() = 1 then pitch camera up 1
   if downkey() = 1 then pitch camera down 1

   `call the pick object function
   obj = pickobject(mousex(),mousey(),3000,0,0,0)

   `color any oject picked red
   if obj <> 0 then color object obj, rgb(250,0,0)

   `position camera (change this to another position and you'll see that the function still works).
   position camera 300, 200, -500

   set cursor 0,0
   print "use arrow keys to pan and tilt camera"
   print "objects will turn red when the mouse cursor it over them"

   sync

loop


end



function pickobject(mx,my,distance,num,flag,exclude)

   `most of this has been taken from http://forum.thegamecreators.com/?m=forum_view&t=154696&b=10
   `the 3D picker code snippet a couple of posts from the top

   dim sx#(2)  :`<<<<<<<<<<<<<<< originally global arrays
   dim sy#(2)  :`<<<<<<<<<<<<<<< originally global arrays
   dim sz#(2)  :`<<<<<<<<<<<<<<< originally global arrays

   `set distance of nearest point
   dist#=1
   for i = 1 to 2
      px#=(((dist#*.8)+.8)*2)/screen width()
      py#=(((dist#*.6)+.6)*2)/screen height()

      CAX#=camera angle x()
      CAY#=camera angle y()
      CAZ#=camera angle z()

      CPX#=camera position x()
      CPY#=camera position y()
      CPZ#=camera position z()

      rem mx#=mousex()    :`<<<<<<<<<<<<<<< original code
      rem my#=mousey()    :`<<<<<<<<<<<<<<< original code
      mx# = mx         :`<<<<<<<<<<<<<<< new so your function will work as you intended
      my# = my         :`<<<<<<<<<<<<<<< new so your function will work as you intended
      X1#=(mx#*px#)-((dist#*.8)+.8)
      Y1#=((dist#*.6)+.6)-(my#*py#)
      Z1#=dist#+1

      cosCAX#=cos(CAX#)
      cosCAY#=cos(CAY#)
      cosCAZ#=cos(CAZ#)
      sinCAX#=sin(CAX#)
      sinCAY#=sin(CAY#)
      sinCAZ#=sin(CAZ#)

      X2#=X1#
      Y2#=cosCAX#*Y1#-sinCAX#*Z1#
      Z2#=SinCAX#*Y1#+CosCAX#*Z1#
      `Yrotate Vector
      X3#=CosCAY#*X2#+SinCAY#*Z2#
      Y3#=Y2#
      Z3#=CosCAY#*Z2#-SinCAY#*X2#
      `Zrotate Vector
      X4#=CosCAZ#*X3#-SinCAZ#*Y3#
      Y4#=SinCAZ#*X3#+CosCAZ#*Y3#
      Z4#=Z3#

      sx#(i)=CPX#+X4#
      sy#(i)=CPY#+Y4#
      sz#(i)=CPZ#+Z4#

      `set distance of furthest point
      dist#=distance

   next i

   object = intersectObjectDBC(num,flag,sx#(1),sy#(1),sz#(1),sx#(2),sy#(2),sz#(2),exclude)
endfunction object





function setupObjectDBC(objNum,groupNum,objectType)
    commonSetup(objNum)

    vertData = get memblock ptr(254)
    objectData = get memblock ptr(255)
    call dll 1,"setupObject",objNum,groupNum,objectType,vertData,objectData

    delete memblock 254
endfunction

function updateObjectDBC(objNum)
    if memblock exist(255)=0 then make memblock 255,24

    write memblock float 255,0,object position x(objNum)
    write memblock float 255,4,object position y(objNum)
    write memblock float 255,8,object position z(objNum)
    write memblock float 255,12,object angle x(objNum)
    write memblock float 255,16,object angle y(objNum)
    write memblock float 255,20,object angle z(objNum)

    objectData = get memblock ptr(255)

    call dll 1,"updateObject",objNum,objectData
endfunction

function commonSetup(objNum)
    if dll exist(1)=0 then load dll "DBCcollision.dll",1
    if memblock exist(255)=0 then make memblock 255,24

    x#=object position x(objNum)
    y#=object position y(objNum)
    z#=object position z(objNum)
    angx#=object angle x(objNum)
    angy#=object angle y(objNum)
    angz#=object angle z(objNum)

    write memblock float 255,0,x#
    write memblock float 255,4,y#
    write memblock float 255,8,z#
    write memblock float 255,12,angx#
    write memblock float 255,16,angy#
    write memblock float 255,20,angz#

    position object objNum,0,0,0
    rotate object objNum,0,0,0
    make mesh from object 255,objNum
    make memblock from mesh 254,255
    delete mesh 255
    position object objNum,x#,y#,z#
    rotate object objNum,angx#,angy#,angz#
endfunction

function intersectObjectDBC(objNum,groupFlag,oldx#,oldy#,oldz#,x#,y#,z#,excludeObj)
    collide=call dll(1,"intersectObject",objNum,groupFlag,oldx#,oldy#,oldz#,x#,y#,z#,excludeObj)
endfunction collide

The code snippet contains all the collision functions, so you won't need an include file (just the dll).

I still don't understand the maths.

Back to top

Profile PM Email

pictionaryjr

15

Years of Service

User Offline

Joined: 12th Mar 2009

Location:

Posted: 8th Feb 2011 05:37 Edited at: 8th Feb 2011 06:00

Link

In the example you posted they use a rotation matrix like me, but thhe part with px and py i don't understand. I don't understand what these points signify.

+ Code Snippet

      px#=(((dist#*.8)+.8)*2)/screen width()
      py#=(((dist#*.6)+.6)*2)/screen height()

      X1#=(mx#*px#)-((dist#*.8)+.8)
      Y1#=((dist#*.6)+.6)-(my#*py#)
      Z1#=dist#+1

In mine. I can explain. In 3D space, the screen is projected from the eye with a certain field of view. What you can do to find the distance from the eye to the screen is use right triangle math by taking the width and height of the screen and divided them by 2, then take the fov and divide it by 2 since we're only using half our screen. We then use SohCahToa and divide half the screen by the tangent of half the fov angle. Like so:

We then use right triangle math again and divide the distance from the eye to the screen by the distance from the mouse to the center of the screen to find the tangent(angle). Of course we need the angle without the tangent. So we'd just use atanfull(distance eye to screen,distance from mouse to center of screen)
Like so:

Since we now have the angle our ray cast is going to sit on. we would use right triangle math one last time and take the distance of the eye to screen,plus the distance we want to cast out and divide it by the tangent of the angle we just figured out to get the 2d position of the point we just casted to in 3d space.
Like so:

Then we use rotation matrix math kind of like we would with an image trying to keep the offset of the plane of the screen we just casted out to stay with the angle of the camera.

Then we would just move the point our ray is casting as many spaces over as our camera is from the origin. We then have our 3d Coordinates. Next we cast the ray from our camera to the point and return the first object, if any, that the ray collides with.

EDIT:
And yes... I'm aware these aren't the best sketchups ever.

EDIT 2:
I whipped up some functions

These are to cast a ray out and get the x, y, and z coordinates for it. Just in case you weren't trying to collide with any objects and just wanted to position an object a certain distance in 3d space where your mouse is. Say a waypoint or something.

function 3drpointx(mx,my,distance)
   cax#=camera angle x()
   cay#=camera angle y()
   cx#=camera position x()
   cy#=camera position y()
   cz#=camera position z()
   fov#=62
   my=screen height()-my
   xdist#=(screen width()/2)/tan(fov#/2)
   ydist#=(screen height()/2)/tan(fov#/2)
   xwidth#=(mx-(screen width()/2))/.95
   ywidth#=(my-(screen height()/2))/1.2
   yang#=atanfull(ydist#,ywidth#)
   zpos#=(((ydist#+distance)/tan(yang#))*sin(cax#))+(distance*cos(cax#))
   xang#=atanfull(xdist#,xwidth#)
   xpos#=(((xdist#+distance)/tan(xang#))*cos(cay#))+(zpos#*sin(cay#))
   xpos#=xpos#+cx#
endfunction xpos#

function 3drpointy(mx,my,distance)
   cax#=camera angle x()
   cay#=camera angle y()
   cx#=camera position x()
   cy#=camera position y()
   cz#=camera position z()
   fov#=62
   my=screen height()-my
   xdist#=(screen width()/2)/tan(fov#/2)
   ydist#=(screen height()/2)/tan(fov#/2)
   xwidth#=(mx-(screen width()/2))/.95
   ywidth#=(my-(screen height()/2))/1.2
   yang#=atanfull(ydist#,ywidth#)
   ypos#=(((ydist#+distance)/tan(yang#))*cos(cax#))+(distance*(-1*sin(cax#)))
   ypos#=ypos#+cy#
endfunction ypos#

function 3drpointz(mx,my,distance)
   cax#=camera angle x()
   cay#=camera angle y()
   cx#=camera position x()
   cy#=camera position y()
   cz#=camera position z()
   fov#=62
   my=screen height()-my
   xdist#=(screen width()/2)/tan(fov#/2)
   ydist#=(screen height()/2)/tan(fov#/2)
   xwidth#=(mx-(screen width()/2))/.95
   ywidth#=(my-(screen height()/2))/1.2
   yang#=atanfull(ydist#,ywidth#)
   ypos#=(((ydist#+distance)/tan(yang#))*cos(cax#))+(distance*(-1*sin(cax#)))
   zpos#=(((ydist#+distance)/tan(yang#))*sin(cax#))+(distance*cos(cax#))
   xang#=atanfull(xdist#,xwidth#)
   zpos#=(((xdist#+distance)/tan(xang#))*(-1*sin(cay#)))+(zpos#*cos(cay#))
   zpos#=zpos#+cz#
endfunction zpos#

+ Code Snippet

function 3drpointx(mx,my,distance)
   cax#=camera angle x()
   cay#=camera angle y()
   cx#=camera position x()
   cy#=camera position y()
   cz#=camera position z()
   fov#=62
   my=screen height()-my
   xdist#=(screen width()/2)/tan(fov#/2)
   ydist#=(screen height()/2)/tan(fov#/2)
   xwidth#=(mx-(screen width()/2))/.95
   ywidth#=(my-(screen height()/2))/1.2
   yang#=atanfull(ydist#,ywidth#)
   zpos#=(((ydist#+distance)/tan(yang#))*sin(cax#))+(distance*cos(cax#))
   xang#=atanfull(xdist#,xwidth#)
   xpos#=(((xdist#+distance)/tan(xang#))*cos(cay#))+(zpos#*sin(cay#))
   xpos#=xpos#+cx#
endfunction xpos#

function 3drpointy(mx,my,distance)
   cax#=camera angle x()
   cay#=camera angle y()
   cx#=camera position x()
   cy#=camera position y()
   cz#=camera position z()
   fov#=62
   my=screen height()-my
   xdist#=(screen width()/2)/tan(fov#/2)
   ydist#=(screen height()/2)/tan(fov#/2)
   xwidth#=(mx-(screen width()/2))/.95
   ywidth#=(my-(screen height()/2))/1.2
   yang#=atanfull(ydist#,ywidth#)
   ypos#=(((ydist#+distance)/tan(yang#))*cos(cax#))+(distance*(-1*sin(cax#)))
   ypos#=ypos#+cy#
endfunction ypos#

function 3drpointz(mx,my,distance)
   cax#=camera angle x()
   cay#=camera angle y()
   cx#=camera position x()
   cy#=camera position y()
   cz#=camera position z()
   fov#=62
   my=screen height()-my
   xdist#=(screen width()/2)/tan(fov#/2)
   ydist#=(screen height()/2)/tan(fov#/2)
   xwidth#=(mx-(screen width()/2))/.95
   ywidth#=(my-(screen height()/2))/1.2
   yang#=atanfull(ydist#,ywidth#)
   ypos#=(((ydist#+distance)/tan(yang#))*cos(cax#))+(distance*(-1*sin(cax#)))
   zpos#=(((ydist#+distance)/tan(yang#))*sin(cax#))+(distance*cos(cax#))
   xang#=atanfull(xdist#,xwidth#)
   zpos#=(((xdist#+distance)/tan(xang#))*(-1*sin(cay#)))+(zpos#*cos(cay#))
   zpos#=zpos#+cz#
endfunction zpos#

These are some functions to rotate a 3d point around the origin.(To move it to the point your trying to rotate around, just add those coordinates to it)

+ Code Snippet

function 3drmx(x#,y#,z#,ax#,ay#)
   zpos#=(y#*sin(ax#))+(z#*cos(ax#))
   xpos#=(x*cos(ay#))+(zpos#*sin(ay#))
endfunction xpos#

function 3drmy(x#,y#,z#,ax#,ay#)
   ypos#=(y*cos(ax#))+(z*(-1*sin(ax#)))
endfunction ypos#

function 3drmz(x#,y#,z#,ax#,ay#)
   zpos#=(y#*sin(ax#))+(z#*cos(ax#))
   zpos#=(x#*(-1*sin(ay#)))+(zpos#*cos(ay#))
endfunction zpos#

TEAM REQUEST FORUMS

Back to top

Profile PM Email

Latch

17

Years of Service

User Offline

Joined: 23rd Jul 2006

Location:

Posted: 8th Feb 2011 20:08

Link

Quote: " px#=(((dist#*.8)+.8)*2)/screen width()
py#=(((dist#*.6)+.6)*2)/screen height()

X1#=(mx#*px#)-((dist#*.8)+.8)
Y1#=((dist#*.6)+.6)-(my#*py#)
Z1#=dist#+1"

This is a hard coded version of finding the endpoints of the mouse vector. The derivation of the .8 and .6 seem to be based on the ratio of 800:600. But it seems to reflect a constant FOV (it's hardcoded). A loose proof of where these values come from might be:

+ Code Snippet

FOV = 3.14/2.905 radians = 1.080895009 radians ~ 62 degrees
800/600 = 1.3333333333
half of FOV ~ 31
half of height = 300
distance to viewplane = unknown
tan(half of FOV) = tan(31) = .600860619
distance to view plane based on half height = 300/tan(31) = 499.28
half of height / distance to view plane = 300/499.28 = .600865249
which proves the relationship to the FOV
tan(31) * 800/600 = .600860619 * 1.333333333 = .8011474
proves the relationship of the ratio of 800/600 to the FOV
so .8 and .6 are the constants

I'm not 100% sure that this is where the values come from, but it makes sense because the proof takes into account the TOA part of SohCahToa right triangle math.

Enjoy your day.

Back to top

Profile PM

pictionaryjr

15

Years of Service

User Offline

Joined: 12th Mar 2009

Location:

Posted: 8th Feb 2011 20:35

Link

Yea true that. I'll have to have a better look at your pseudo code when i get back on. Maybe it can help my code to be more accurate.

TEAM REQUEST FORUMS

Back to top

Profile PM Email

pictionaryjr

15

Years of Service

User Offline

Joined: 12th Mar 2009

Location:

Posted: 1st Apr 2011 10:09

Link

Hey just wanted to post back on this thread. I got it working perfectly. Kind of jumbled what latch said, what 29 games posted and what I had. The way of getting the ratios. Latch you were correct. His ratios weren't dead on the money and only worked for screens that had a 4 to 3 ratio. I changed it taking your advice on the FOV and made it so it give the correct ratios. Then I just put it to a point I understood. I still can't understand why my way failed me. But regardless. I've figured it out now. No bother.

pickobject function:

+ Code Snippet

function pickobject(mx,my,distance#,num,flag,exclude)
   cax#=camera angle x()
   cay#=camera angle y()
   cx#=camera position x()
   cy#=camera position y()
   cz#=camera position z()
   width#=screen width()
   height#=screen height()
   mx#=mx
   my#=my
   fov#=(3.14/2.905)*57.2957795
   screeny#=tan(fov#/2)
   screenx#=screeny#*(width#/height#)
   px#=(((distance#*screenx#)+screenx#)*2)/width#
   py#=(((distance#*screeny#)+screeny#)*2)/height#
   xpos#=(mx#*px#)-((distance#*screenx#)+screenx#)
   ypos#=((distance#*screeny#)+screeny#)-(my#*py#)
   zpos#=distance#
   typos#=(ypos#*cos(cax#))+(zpos#*(-1*sin(cax#)))
   zpos#=(ypos#*sin(cax#))+(zpos#*cos(cax#))
   ypos#=typos#
   txpos#=(xpos#*cos(cay#))+(zpos#*sin(cay#))
   zpos#=(xpos#*(-1*sin(cay#)))+(zpos#*cos(cay#))
   xpos#=txpos#
   xpos#=xpos#+cx#
   ypos#=ypos#+cy#
   zpos#=zpos#+cz#
   object=intersectObjectDBC(num,flag,cx#,cy#,cz#,xpos#,ypos#,zpos#,exclude)
endfunction object

3D ray casting functions:

function threedrpointx(mx,my,distance#) 
   cax#=camera angle x()
   cay#=camera angle y()
   cx#=camera position x()
   width#=screen width()
   height#=screen height()
   mx#=mx
   my#=my
   fov#=(3.14/2.905)*57.2957795
   screeny#=tan(fov#/2)
   screenx#=screeny#*(width#/height#)
   px#=(((distance#*screenx#)+screenx#)*2)/width#
   py#=(((distance#*screeny#)+screeny#)*2)/height#
   xpos#=(mx#*px#)-((distance#*screenx#)+screenx#)
   ypos#=((distance#*screeny#)+screeny#)-(my#*py#)
   zpos#=distance#
   zpos#=(ypos#*sin(cax#))+(zpos#*cos(cax#))
   xpos#=(xpos#*cos(cay#))+(zpos#*sin(cay#))
   xpos#=xpos#+cx#
endfunction xpos#

function threedrpointy(mx,my,distance#)
   cax#=camera angle x()
   cy#=camera position y()
   height#=screen height()
   my#=my
   fov#=(3.14/2.905)*57.2957795
   screeny#=tan(fov#/2)
   py#=(((distance#*screeny#)+screeny#)*2)/height#
   ypos#=((distance#*screeny#)+screeny#)-(my#*py#)
   zpos#=distance#
   ypos#=(ypos#*cos(cax#))+(zpos#*(-1*sin(cax#)))
   ypos#=ypos#+cy#
endfunction ypos#

function threedrpointz(mx,my,distance#)
   cax#=camera angle x()
   cay#=camera angle y()
   cz#=camera position z()
   width#=screen width()
   height#=screen height()
   mx#=mx
   my#=my
   fov#=(3.14/2.905)*57.2957795
   screeny#=tan(fov#/2)
   screenx#=screeny#*(width#/height#)
   px#=(((distance#*screenx#)+screenx#)*2)/width#
   py#=(((distance#*screeny#)+screeny#)*2)/height#
   xpos#=(mx#*px#)-((distance#*screenx#)+screenx#)
   ypos#=((distance#*screeny#)+screeny#)-(my#*py#)
   zpos#=distance#
   zpos#=(ypos#*sin(cax#))+(zpos#*cos(cax#))
   zpos#=(xpos#*(-1*sin(cay#)))+(zpos#*cos(cay#))
   zpos#=zpos#+cz#
endfunction zpos#

+ Code Snippet

function threedrpointx(mx,my,distance#) 
   cax#=camera angle x()
   cay#=camera angle y()
   cx#=camera position x()
   width#=screen width()
   height#=screen height()
   mx#=mx
   my#=my
   fov#=(3.14/2.905)*57.2957795
   screeny#=tan(fov#/2)
   screenx#=screeny#*(width#/height#)
   px#=(((distance#*screenx#)+screenx#)*2)/width#
   py#=(((distance#*screeny#)+screeny#)*2)/height#
   xpos#=(mx#*px#)-((distance#*screenx#)+screenx#)
   ypos#=((distance#*screeny#)+screeny#)-(my#*py#)
   zpos#=distance#
   zpos#=(ypos#*sin(cax#))+(zpos#*cos(cax#))
   xpos#=(xpos#*cos(cay#))+(zpos#*sin(cay#))
   xpos#=xpos#+cx#
endfunction xpos#

function threedrpointy(mx,my,distance#)
   cax#=camera angle x()
   cy#=camera position y()
   height#=screen height()
   my#=my
   fov#=(3.14/2.905)*57.2957795
   screeny#=tan(fov#/2)
   py#=(((distance#*screeny#)+screeny#)*2)/height#
   ypos#=((distance#*screeny#)+screeny#)-(my#*py#)
   zpos#=distance#
   ypos#=(ypos#*cos(cax#))+(zpos#*(-1*sin(cax#)))
   ypos#=ypos#+cy#
endfunction ypos#

function threedrpointz(mx,my,distance#)
   cax#=camera angle x()
   cay#=camera angle y()
   cz#=camera position z()
   width#=screen width()
   height#=screen height()
   mx#=mx
   my#=my
   fov#=(3.14/2.905)*57.2957795
   screeny#=tan(fov#/2)
   screenx#=screeny#*(width#/height#)
   px#=(((distance#*screenx#)+screenx#)*2)/width#
   py#=(((distance#*screeny#)+screeny#)*2)/height#
   xpos#=(mx#*px#)-((distance#*screenx#)+screenx#)
   ypos#=((distance#*screeny#)+screeny#)-(my#*py#)
   zpos#=distance#
   zpos#=(ypos#*sin(cax#))+(zpos#*cos(cax#))
   zpos#=(xpos#*(-1*sin(cay#)))+(zpos#*cos(cay#))
   zpos#=zpos#+cz#
endfunction zpos#

Experimental Games Blog

Back to top

Profile PM Email

29 games

18

Years of Service

User Offline

Joined: 23rd Nov 2005

Location: not entirely sure

Posted: 6th Apr 2011 21:56

Link

All of those work really well.

Back to top

Profile PM Email

pictionaryjr

15

Years of Service

User Offline

Joined: 12th Mar 2009

Location:

Posted: 8th Apr 2011 00:26

Link

thank you. here's the fixed 3drotation matrix functions too. you would just have to add your current positions to the output if you were planning on doing it elsewhere

+ Code Snippet

function threedrmx(x#,y#,z#,ax#,ay#)
   zpos#=(y#*sin(ax#))+(z#*cos(ax#))
   xpos#=(x#*cos(ay#))+(zpos#*sin(ay#))
endfunction xpos#

function threedrmy(x#,y#,z#,ax#,ay#)
   ypos#=(y#*cos(ax#))+(z#*(-1*sin(ax#)))
endfunction ypos#

function threedrmz(x#,y#,z#,ax#,ay#)
   zpos#=(y#*sin(ax#))+(z#*cos(ax#))
   zpos#=(x#*(-1*sin(ay#)))+(zpos#*cos(ay#))
endfunction zpos#

Experimental Games Blog
Experimental Games YouTube Channel

Back to top

Profile PM Email

pictionaryjr

15

Years of Service

User Offline

Joined: 12th Mar 2009

Location:

Posted: 8th Apr 2011 01:58

Link

this is a quick question for latch. Why is the mouse position a little offset like that. it explains why my right triangle math wasnt working. the mouse has a 2.5... offset. i can't see the reasoning behind this

Experimental Games Blog
Experimental Games YouTube Channel

Back to top

Profile PM Email

Latch

17

Years of Service

User Offline

Joined: 23rd Jul 2006

Location:

Posted: 9th Apr 2011 20:21

Link

@pictionary

Quote: "this is a quick question for latch. Why is the mouse position a little offset like that. it explains why my right triangle math wasnt working. the mouse has a 2.5... offset. i can't see the reasoning behind this"

There's something not quite right about the ratio of width to height and the mouse position. I can't quite see it because the order of your equations are different than what I'm used to. The end position of the ray is too high on the y axis. This may be what is skewing other things.

There is something to keep in mind as screen resolutions and camera views change. If you change the camera view, for example, to 800 x 200 , the FOV will still be the default 62 degrees. However, because the half y and half x resolutions will have a different ratio (400 x 100 ) you would need to calculate TWO Z distances to the viewing plane or else there would be skewing.

1 z distance based on the width
1 z distance based on the height

For each x and y screen position calculation, you would have to use the respective z distance in the calculations.

Does that make any sense?

Enjoy your day.

Back to top

Profile PM

Sorry your browser is not supported!

DarkBASIC Discussion / 3D Rotation Matrix