3rd Person View Gone Awry - GameCreators Forum

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Relativity

20

Years of Service

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Joined: 29th Mar 2005

Location: Position is relative.

Posted: 26th Aug 2005 03:10

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These are two attempts at a very simple third person view. Both have problems I don't understand. The first uses standard Euler rotation:

`  by the SITHSPAWN
`  ----------------
AUTOCAM OFF
HIDE MOUSE
POSITION CAMERA 0,0,0
SYNC ON
INK RGB(255,255,255),1

MAKE OBJECT CUBE 2,2
COLOR OBJECT 2,RGB(0,0,0)
POSITION OBJECT 2,0,0,0

MAKE OBJECT CUBE 3,20
COLOR OBJECT 3,RGB(0,255,0)
POSITION OBJECT 3,0,30,0

MAKE OBJECT CUBE 4,30
COLOR OBJECT 4,RGB(0,0,255)
POSITION OBJECT 4,0,0,50

MAKE OBJECT CUBE 5,45
COLOR OBJECT 5,RGB(255,0,0)
POSITION OBJECT 5,25,0,0

COLOR BACKDROP RGB(155,155,155)

ROTATE OBJECT 2,0,0,0

DO
   IF KEYSTATE(17)=1 THEN MOVE OBJECT 2,5
   IF KEYSTATE(31)=1 THEN MOVE OBJECT 2,-5
   IF KEYSTATE(30)=1
      YROTATE OBJECT 2,WRAPVALUE(MY#-90)
      MOVE OBJECT 2,5
      YROTATE OBJECT 2,WRAPVALUE(MY#+90)
   ENDIF
   IF KEYSTATE(32)=1
      YROTATE OBJECT 2,WRAPVALUE(MY#+90)
      MOVE OBJECT 2,5
      YROTATE OBJECT 2,WRAPVALUE(MY#-90)
   ENDIF

IF KEYSTATE(16)=1 THEN MZ#=WRAPVALUE(MZ#-5)
   IF KEYSTATE(18)=1 THEN MZ#=WRAPVALUE(MZ#+5)

MX#=WRAPVALUE(MX#+MOUSEMOVEY())
   MY#=WRAPVALUE(MY#+MOUSEMOVEX())

ROTATE OBJECT 2,MX#,MY#,MZ#

ROTATE CAMERA MX#,MY#,MZ#
   POSITION CAMERA OBJECT POSITION X(2),OBJECT POSITION Y(2),OBJECT POSITION Z(2)
   MOVE CAMERA -10

SET CURSOR 0,0
   PRINT OBJECT ANGLE X(2)," ",OBJECT ANGLE Y(2)," ",OBJECT ANGLE Z(2)
   PRINT CAMERA ANGLE X()," ",CAMERA ANGLE Y()," ",CAMERA ANGLE Z()

SYNC

LOOP

+ Code Snippet

`  by the SITHSPAWN
`  ----------------
AUTOCAM OFF
HIDE MOUSE
POSITION CAMERA 0,0,0
SYNC ON
INK RGB(255,255,255),1

MAKE OBJECT CUBE 2,2
COLOR OBJECT 2,RGB(0,0,0)
POSITION OBJECT 2,0,0,0

MAKE OBJECT CUBE 3,20
COLOR OBJECT 3,RGB(0,255,0)
POSITION OBJECT 3,0,30,0

MAKE OBJECT CUBE 4,30
COLOR OBJECT 4,RGB(0,0,255)
POSITION OBJECT 4,0,0,50

MAKE OBJECT CUBE 5,45
COLOR OBJECT 5,RGB(255,0,0)
POSITION OBJECT 5,25,0,0

COLOR BACKDROP RGB(155,155,155)

ROTATE OBJECT 2,0,0,0

DO
   IF KEYSTATE(17)=1 THEN MOVE OBJECT 2,5
   IF KEYSTATE(31)=1 THEN MOVE OBJECT 2,-5
   IF KEYSTATE(30)=1
      YROTATE OBJECT 2,WRAPVALUE(MY#-90)
      MOVE OBJECT 2,5
      YROTATE OBJECT 2,WRAPVALUE(MY#+90)
   ENDIF
   IF KEYSTATE(32)=1
      YROTATE OBJECT 2,WRAPVALUE(MY#+90)
      MOVE OBJECT 2,5
      YROTATE OBJECT 2,WRAPVALUE(MY#-90)
   ENDIF

   IF KEYSTATE(16)=1 THEN MZ#=WRAPVALUE(MZ#-5)
   IF KEYSTATE(18)=1 THEN MZ#=WRAPVALUE(MZ#+5)

   MX#=WRAPVALUE(MX#+MOUSEMOVEY())
   MY#=WRAPVALUE(MY#+MOUSEMOVEX())

   ROTATE OBJECT 2,MX#,MY#,MZ#

   ROTATE CAMERA MX#,MY#,MZ#
   POSITION CAMERA OBJECT POSITION X(2),OBJECT POSITION Y(2),OBJECT POSITION Z(2)
   MOVE CAMERA -10

   SET CURSOR 0,0
   PRINT OBJECT ANGLE X(2)," ",OBJECT ANGLE Y(2)," ",OBJECT ANGLE Z(2)
   PRINT CAMERA ANGLE X()," ",CAMERA ANGLE Y()," ",CAMERA ANGLE Z()

   SYNC

LOOP

The big problem with that one is that the cube doesn't face the same direction as the camera when you move the mouse.

The second one is the same thing only with Free Flight Rotation. It looks like it works fine at first glance but when you move the mouse around for a while you will notice that it starts to move around the z-axis.

`  by the SITHSPAWN
`  ----------------
AUTOCAM OFF
HIDE MOUSE
POSITION CAMERA 0,0,0
SYNC ON
INK RGB(255,255,255),1
DRAW TO FRONT
REMSTART
MAKE OBJECT TRIANGLE 1,0,0,0,0,0,0,0,0,0
POSITION OBJECT 1,0,0,0
HIDE OBJECT 1
REMEND
MAKE OBJECT CUBE 2,2
COLOR OBJECT 2,RGB(0,0,0)
POSITION OBJECT 2,0,0,0

MAKE OBJECT CUBE 3,20
COLOR OBJECT 3,RGB(0,255,0)
POSITION OBJECT 3,0,30,0

MAKE OBJECT CUBE 4,30
COLOR OBJECT 4,RGB(0,0,255)
POSITION OBJECT 4,0,0,50

MAKE OBJECT CUBE 5,45
COLOR OBJECT 5,RGB(255,0,0)
POSITION OBJECT 5,25,0,0

COLOR BACKDROP RGB(155,155,155)

ROTATE OBJECT 2,0,0,0

DO
   IF KEYSTATE(17)=1 THEN MOVE OBJECT 2,5
   IF KEYSTATE(31)=1 THEN MOVE OBJECT 2,-5
   IF KEYSTATE(30)=1
      YROTATE OBJECT 2,WRAPVALUE(MY#-90)
      MOVE OBJECT 2,5
      YROTATE OBJECT 2,WRAPVALUE(MY#+90)
   ENDIF
   IF KEYSTATE(32)=1
      YROTATE OBJECT 2,WRAPVALUE(MY#+90)
      MOVE OBJECT 2,5
      YROTATE OBJECT 2,WRAPVALUE(MY#-90)
   ENDIF

IF KEYSTATE(16)=1 THEN MZ#=WRAPVALUE(MZ#-5)
   IF KEYSTATE(18)=1 THEN MZ#=WRAPVALUE(MZ#+5)

PITCH OBJECT UP 2,INT(0-MOUSEMOVEY())
   TURN OBJECT RIGHT 2,INT(MOUSEMOVEX())

ROTATE CAMERA OBJECT ANGLE X(2),OBJECT ANGLE Y(2),OBJECT ANGLE Z(2)
   POSITION CAMERA OBJECT POSITION X(2),OBJECT POSITION Y(2),OBJECT POSITION Z(2)
   MOVE CAMERA -10

SET CURSOR 0,0
   PRINT OBJECT ANGLE X(2)," ",OBJECT ANGLE Y(2)," ",OBJECT ANGLE Z(2)
   PRINT CAMERA ANGLE X()," ",CAMERA ANGLE Y()," ",CAMERA ANGLE Z()

SYNC

LOOP

+ Code Snippet

`  by the SITHSPAWN
`  ----------------
AUTOCAM OFF
HIDE MOUSE
POSITION CAMERA 0,0,0
SYNC ON
INK RGB(255,255,255),1
DRAW TO FRONT
REMSTART
MAKE OBJECT TRIANGLE 1,0,0,0,0,0,0,0,0,0
POSITION OBJECT 1,0,0,0
HIDE OBJECT 1
REMEND
MAKE OBJECT CUBE 2,2
COLOR OBJECT 2,RGB(0,0,0)
POSITION OBJECT 2,0,0,0

MAKE OBJECT CUBE 3,20
COLOR OBJECT 3,RGB(0,255,0)
POSITION OBJECT 3,0,30,0

MAKE OBJECT CUBE 4,30
COLOR OBJECT 4,RGB(0,0,255)
POSITION OBJECT 4,0,0,50

MAKE OBJECT CUBE 5,45
COLOR OBJECT 5,RGB(255,0,0)
POSITION OBJECT 5,25,0,0

COLOR BACKDROP RGB(155,155,155)

ROTATE OBJECT 2,0,0,0

DO
   IF KEYSTATE(17)=1 THEN MOVE OBJECT 2,5
   IF KEYSTATE(31)=1 THEN MOVE OBJECT 2,-5
   IF KEYSTATE(30)=1
      YROTATE OBJECT 2,WRAPVALUE(MY#-90)
      MOVE OBJECT 2,5
      YROTATE OBJECT 2,WRAPVALUE(MY#+90)
   ENDIF
   IF KEYSTATE(32)=1
      YROTATE OBJECT 2,WRAPVALUE(MY#+90)
      MOVE OBJECT 2,5
      YROTATE OBJECT 2,WRAPVALUE(MY#-90)
   ENDIF

   IF KEYSTATE(16)=1 THEN MZ#=WRAPVALUE(MZ#-5)
   IF KEYSTATE(18)=1 THEN MZ#=WRAPVALUE(MZ#+5)


   PITCH OBJECT UP 2,INT(0-MOUSEMOVEY())
   TURN OBJECT RIGHT 2,INT(MOUSEMOVEX())

   ROTATE CAMERA OBJECT ANGLE X(2),OBJECT ANGLE Y(2),OBJECT ANGLE Z(2)
   POSITION CAMERA OBJECT POSITION X(2),OBJECT POSITION Y(2),OBJECT POSITION Z(2)
   MOVE CAMERA -10

   SET CURSOR 0,0
   PRINT OBJECT ANGLE X(2)," ",OBJECT ANGLE Y(2)," ",OBJECT ANGLE Z(2)
   PRINT CAMERA ANGLE X()," ",CAMERA ANGLE Y()," ",CAMERA ANGLE Z()

   SYNC

LOOP

I tried using INT() on that one, thinking the problem might be round-off error with the MOUSEMOVEX() and MOUSEMOVEY() commands but it didn't seem to have an effect. I would appreciate any thoughts to the reasons to these two problems. Thanks.

This is a test. This is only a test. If this were an actual emergency you'd all be dead.

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Xenocythe

19

Years of Service

User Offline

Joined: 26th May 2005

Location: You Essay.

Posted: 26th Aug 2005 03:22

Link

Try this. (If the object your moving is object 2)

+ Code Snippet

rem Get current object position
posx#=object position x(2)
posy#=object position y(2)
posz#=object position z(2)
rem Use camera tracker to follow player object
angle#=object angle y(2)
camdist#=25.0 : camhigh#=posy#+10.0 : camfade#=3.5
set camera to follow posx#,posy#,posz#,angle#,camdist#,camhigh#,camfade#,1

Put that in the loop in place of your camera commands. Camdist# and camhigh# are the value you need to change if you want to move the camera to follow farther or away, higher or lower.

Happy game making.

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NanoBrain

20

Years of Service

User Offline

Joined: 20th Jan 2005

Location: Portland, OR

Posted: 26th Aug 2005 12:56

Link

SithSpawn,

Here is a math alternative.

+ Code Snippet

sync on
sync rate 60
hide mouse

make object cube 1,5
position object 1,0,2.5,0
color object 1,rgb(255,0,0)
make object plain 2,100,100
xrotate object 2,90
REM << make camera look down a bit
xrotate camera 20
REM << distance camera will be from object
camdist = 20

REM <<<<<<<<<<<<<< main loop >>>>>>>>>>>>>>>>
do

REM << rotate object
if rightkey() = 1 then objangy = wrapvalue(objangy + 2)
if leftkey() = 1 then objangy = wrapvalue(objangy - 2)
yrotate object 1,objangy
REM << move object foward
if upkey() = 1 then move object 1,2

REM << get camera coordinates from object coordinates
camx# = object position x(1) + (sin(objangy + 180) * camdist)
camz# = object position z(1) + (cos(objangy + 180) * camdist)
REM << face camera at same y angle as object and reposition it
yrotate camera objangy
position camera camx#,10,camz#

sync
loop

+NanoBrain+

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Relativity

20

Years of Service

User Offline

Joined: 29th Mar 2005

Location: Position is relative.

Posted: 26th Aug 2005 17:03

Link

Perhaps I should have specified that the object the camera is following is changing its x-, y-, and z-angles and doesn't stay in one plain. More like a space simulator in 3rd person.

Also, I'd still like to know why the two snippets I posted above have problems.

This is a test. This is only a test. If this were an actual emergency you'd all be dead.

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TDK

Retired Moderator

22

Years of Service

User Offline

Joined: 19th Nov 2002

Location: UK

Posted: 26th Aug 2005 22:59

Link

There is a known problem with DB Classic 'out of the box' when it comes to object rotation, but I don't remember exactly what it was or what you do to get round it.

All I remember is that it's something to do with 'gimble' or 'gimbal' - whatever that is lol, and I think Fix Object Pivot came into the fix somewhere!

Sorry It's not much help (not my field of expertise I'm afraid), but this might point you in the right direction to ask for further help.

TDK_Man

A New Alternative IDE For DB Classic!

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