3D lock on - GameCreators Forum

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Zotoaster

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Joined: 20th Dec 2004

Location: Scotland

Posted: 14th Dec 2005 20:08

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This is a function to lock something on from a 3D perspective, I couldn't handle locking it on from a 2D perspective.

Not only can this be used to lock something on, I personally would find it usefull to find the point I'm aiming at on an fps, and can also be used as an alternative to move object or move camera (though you would have to take away some stuff from it first).

One problem, I can't make it alter the x and Y coords. ONly the distance from the camera. Does anyone know how to get the inverse Sin and inverse Cos of something in DBPro?

Anyway, here's some code.

(Oh btw, you need to use the function in the main loop)

+ Code Snippet

`Setup
sync on : sync rate 60
set display mode 1024,768,16
set window on : maximize window

`Create object to lock on
make object plain 1,1,1

`Create world
make matrix 1,10000,10000,50,50

`*Main Loop*
Do

`Control camera
rotate camera wrapvalue(camera angle x()+mousemovey()),wrapvalue(camera angle y()+mousemovex()),0

`Lock object on
lock_on(1,10)

`*End Loop*
Sync
Loop

`*Functions*
Function Lock_on(obj,z)
ax=camera angle x() : ay=camera angle y() : az=camera angle z()
cx=camera position x() : cy=camera position y() : cz=camera position z()
position object obj,cx+(sin(ay)*cos(ax))*z,cy-sin(ax)*z,cz+(cos(ay)*cos(ax))*z
point object obj,cx,cy,cz
endfunction

And the function:

Lock_On(object number,distance from camera)

+ Code Snippet

`*Functions*
Function Lock_on(obj,z)
ax=camera angle x() : ay=camera angle y() : az=camera angle z()
cx=camera position x() : cy=camera position y() : cz=camera position z()
position object obj,cx+(sin(ay)*cos(ax))*z,cy-sin(ax)*z,cz+(cos(ay)*cos(ax))*z
point object obj,cx,cy,cz
endfunction

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Darkbasic MADPSP

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Joined: 15th Jun 2005

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Posted: 14th Dec 2005 20:17

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+ Code Snippet

lock object on 1
position object x, y, z
do
control camera using arrow keys 0, 1, 1
loop

Can't that do the shame job

but nice code

Experienced DB http://www.greatgames3d.com (work in progress site)

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Zotoaster

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Posted: 14th Dec 2005 20:19

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not really, notice I said that I didn't like doing it from a 2D perspective. i.e. once you've locked it on normally, when you move it it treats it like a 2d sprite on the screen, as you position it with 2d coords. With this it is positioned with 3d coordinates (well only the z one so far

)

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Darkbasic MADPSP

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Posted: 14th Dec 2005 20:21

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Quote: "LOCK OBJECT ON
This command will lock the specified 3D object to the screen. Locking objects to the screen commands the
object to completely ignore the camera's influence. A locked object will be positioned as though the
camera had never been altered from its default orientation. To make locked objects visible, simply set the
Z position to a significant positive value. The Object Number should be specified using an integer value.
"

Experienced DB http://www.greatgames3d.com (work in progress site)

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Zotoaster

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Posted: 14th Dec 2005 20:24

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Yeah it will to the 3d screen, but it will have 2d coords.

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Sven B

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Joined: 5th Jan 2005

Location: Belgium

Posted: 15th Dec 2005 18:23

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Quote: "Does anyone know how to get the inverse Sin and inverse Cos of something in DBPro"

atan(), acos() and asin().

Immunity and Annihalation makes Immunihalation...

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Zotoaster

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Posted: 15th Dec 2005 19:37

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oh.. oh yeah, thanks

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Sven B

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Posted: 16th Dec 2005 14:03

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np

Immunity and Annihalation makes Immunihalation...

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Turoid

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Joined: 1st Nov 2003

Location: The Netherlands

Posted: 16th Dec 2005 22:47

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Quote: "Can't that do the shame job but nice code"

It will do about the same job yes

But if you are working with some lights in your map, and you use the lock object on command, the light doesn't affect the gun, with that function it does

.::Studying game design at the moment::.

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Morcilla

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Location: Spain

Posted: 26th Dec 2005 12:42

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Hi,
this is another lock on function. The x,y problem is solved, you have to feed the values, of course:

+ Code Snippet

Function Lock_on(Lock_obj, Lock_x, Lock_y, Lock_z)
cx=camera position x()
cy=camera position y()
cz=camera position z()
Pick Screen  Lock_x, Lock_y, Lock_z
Position Object Lock_obj, Get Pick VectorX()+cx, Get Pick VectorY()+cy, Get Pick VectorZ()+cz
Point Object Lock_obj, cx, cy, cz
endfunction

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Codelike

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Joined: 13th Dec 2005

Location: DBP - Scouseland

Posted: 16th Jan 2006 19:40

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Here's another version with full x,y,z. No sin/cos is used. This uses keys.

` this is designed to give a full, mobile, 3rd person view around the main object
` use arrow keys for x/y axis. use shift & control for z axis.

x#=0
y#=0
z#=-10

sync on
hide mouse
position camera 0,x#,y#,z#
autocam off

` un-rem the command if you would like to solidify the objects with regard to the camera
rem automatic camera collision 0,2,0

cls
color backdrop black

make object cube 1,2
make object sphere 2,1
position object 1,0,0,0
position object 2,0,0,30

do
sync
gosub _cameraposition
if escapekey()=1 then end
loop

_cameraposition:
if upkey()=1 then inc y#,0.1 : position camera 0,x#,y#,z# : point camera 0,0,0,0
if downkey()=1 then dec y#,0.1 : position camera 0,x#,y#,z# : point camera 0,0,0,0
if leftkey()=1 then inc x#,0.1 : position camera 0,x#,y#,z# : point camera 0,0,0,0
if rightkey()=1 then dec x#,0.1 : position camera 0,x#,y#,z# : point camera 0,0,0,0
if shiftkey()=1 then inc z#,0.1 : position camera 0,x#,y#,z# : point camera 0,0,0,0
if controlkey()=1 then dec z#,0.1 : position camera 0,x#,y#,z# : point camera 0,0,0,0
return

+ Code Snippet

` this is designed to give a full, mobile, 3rd person view around the main object
` use arrow keys for x/y axis. use shift & control for z axis.

x#=0
y#=0
z#=-10

sync on
hide mouse
position camera 0,x#,y#,z#
autocam off

` un-rem the command if you would like to solidify the objects with regard to the camera
rem automatic camera collision 0,2,0

cls
color backdrop black

make object cube 1,2
make object sphere 2,1
position object 1,0,0,0
position object 2,0,0,30

do
sync
gosub _cameraposition
if escapekey()=1 then end
loop

_cameraposition:
if upkey()=1 then inc y#,0.1 : position camera 0,x#,y#,z# : point camera 0,0,0,0
if downkey()=1 then dec y#,0.1 : position camera 0,x#,y#,z# : point camera 0,0,0,0
if leftkey()=1 then inc x#,0.1 : position camera 0,x#,y#,z# : point camera 0,0,0,0
if rightkey()=1 then dec x#,0.1 : position camera 0,x#,y#,z# : point camera 0,0,0,0
if shiftkey()=1 then inc z#,0.1 : position camera 0,x#,y#,z# : point camera 0,0,0,0
if controlkey()=1 then dec z#,0.1 : position camera 0,x#,y#,z# : point camera 0,0,0,0
return

I have an XP3000+, 1.5gb DDR333, a 6600GT and I'm programming 3k text-based exe's?!

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Milkman

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Joined: 30th Nov 2005

Location: United States

Posted: 17th Jan 2006 00:01 Edited at: 17th Jan 2006 00:37

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nice, but thats not what zotoaster meant by "3d lock on"... he meant to lock an object to the screen, such as a gun in an fps.

anyways, here is my function for doing so:

+ Code Snippet

function lockon(object,x#,y#,z#)
   position object object,camera position x(),camera position y(),camera position z()
   rotate object object,camera angle x(),camera angle y(),camera angle z()
   move object object,z#
   move object right object,x#
   move object up object,y#
endfunction

works with x, y, and z, and doesn't use sin/cos!

might be [slightly] slower than with sin and cos though

"Genius is 1% inspiration and 99% perspiration"

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Uncle Sam

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Joined: 23rd Jul 2005

Location: West Coast, USA

Posted: 17th Jan 2006 00:11

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Thanks Zoto! Can I use this?

--------------
Uncle Sam

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Zotoaster

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Joined: 20th Dec 2004

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Posted: 17th Jan 2006 00:14

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Sure thing

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Codelike

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Joined: 13th Dec 2005

Location: DBP - Scouseland

Posted: 17th Jan 2006 03:43

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Thanks xMik, I missed the point of that one! I was camera locking onto the 'character', rather then the 'gun', I think!
I hope someone can use it, though...

I have an XP3000+, 1.5gb DDR333, a 6600GT and I'm programming 3k text-based exe's?!

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Code Snippets / 3D lock on