Using POINT OBJECT to keep PLAINs facing towards camera?

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gbark

18

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Joined: 14th Oct 2005

Location: US - Virginia

Posted: 15th Oct 2005 00:56

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Hello, this is my first post on this forum, so I'll just give a little intro.

I've been lurking here for a while and reading up on DarkBASIC. I have some experience with computer programming (mostly with JavaScript and Liberty BASIC, I've dabbled a bit with C++, but I couldn't figure out how to use the editor I was using, so I didn't get very far with that.

) so I'm already used to variables, loops, etc, and I've worked with 3D also (POV-RAY and CAD programs mostly), so I'm also familiar with 3D coordinates, axis rotations, etc. This is my first foray into putting the two together however, so it's pretty exciting for me.

Anyways, downloaded the trial a couple of days ago, almost finished with my very first game.

It's a simple game where you're running around a matrix, collecting blue crystals, and trying to get more than the CPU before time runs out. I've got all of the main routines done, the menu system, the game engine, the AI, etc, so I decided to start adding the bells and whistles. Right now I'm trying to add a small sparkle effect whenever you get a crystal, but I can't get the sparkle to align to the camera's position.

I did a forum search, seems other people also had this problem, but none of the suggestions offered seemed to worked for me.

Here's my code:

+ Code Snippet

sync on
sync rate 40
backdrop on
color backdrop rgb(32, 32, 32)

` Load texture
remstart
load bitmap "..\CrystalCatcher\BmpSparkle.bmp", 1
set current bitmap 1

get image 1, 0, 0, 45, 45
mirror bitmap 1
get image 2, 0, 0, 45, 45

set current bitmap 0
delete bitmap 1
remend

` Make object for camera to look at
make object plain 1, 15, 15
position object 1, 0, 0, 0
rotate object 1, 0, 180, 0
fix object pivot 1
set object 1, 1, 0, 1, 1, 0, 0, 0
`texture object 1, 1

` Default camera position
camA# = 0
cX# = newxvalue(0, camA#, 30)
cY# = newyvalue(0, camA#, 30)
cZ# = newzvalue(0, camA#, 30)
position camera cX#, cY#, cZ#
point camera 0, 0, 0

do
	` Update camera position
	camA# = wrapvalue(camA# + 1)
	cX# = newxvalue(0, camA#, 30)
	cY# = newyvalue(0, camA#, 30)
	cZ# = newzvalue(0, camA#, 30)
	position camera cX#, cY#, cZ#
	point camera 0, 0, 0

	` Update object orientation
	point object 1, camera position x(), camera position y(), camera position z()

	sync
loop

I'm pretty much stumped. Anybody have any solutions?

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RUCCUS

19

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Joined: 11th Dec 2004

Location: Canada

Posted: 15th Oct 2005 04:43 Edited at: 15th Oct 2005 04:44

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Well you didnt post a question but to do what youre asking shouldnt be too hard...

+ Code Snippet

POINT OBJECT Object Number, CAMERA POSITION X(), CAMERA POSITION Y(), CAMERA POSITION Z()

Alternitavely, you could use LOCK OBJECT ON to lock the object to the screen, the pro being easier calculations for the computer, the con being the object wont change in size as you get closer and farther from the plain.

Note that you'll have to first use either the xrotate command or zrotate command to rotate the plain 90 degrees before you can point it to the camera, like so:

+ Code Snippet

XROTATE OBJECT Object Number, WRAPVALUE(OBJECT ANGLE X(Object Number)+90)

Goodluck, hope it helps.
- RUCCUS

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gbark

18

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Joined: 14th Oct 2005

Location: US - Virginia

Posted: 15th Oct 2005 04:57

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Hi RUCCUS,

I don't know what happened, I had made my post, submitted it, waited for it to be approved, and once the thread appeared, my post was blank!

Anyway...

Yeah, basically I want a textured PLAIN to always face towards the camera. I'm using the camera x, y, and z coords with POINT object just like you suggested, but it just doesn't seem to work.

Here's my code, you'll see it doesn't work as expected:

+ Code Snippet

sync rate 40
backdrop on
color backdrop rgb(32, 32, 32)

` Load texture
remstart
load bitmap "..\CrystalCatcher\BmpSparkle.bmp", 1
set current bitmap 1

get image 1, 0, 0, 45, 45
mirror bitmap 1
get image 2, 0, 0, 45, 45

set current bitmap 0
delete bitmap 1
remend

` Make object for camera to look at
make object plain 1, 15, 15
position object 1, 0, 0, 0
rotate object 1, 0, 180, 0
fix object pivot 1
set object 1, 1, 0, 1, 1, 0, 0, 0
`texture object 1, 1

` Default camera position
camA# = 0
cX# = newxvalue(0, camA#, 30)
cY# = newyvalue(0, camA#, 30)
cZ# = newzvalue(0, camA#, 30)
position camera cX#, cY#, cZ#
point camera 0, 0, 0

do
	` Update camera position
	camA# = wrapvalue(camA# + 1)
	cX# = newxvalue(0, camA#, 30)
	cY# = newyvalue(0, camA#, 30)
	cZ# = newzvalue(0, camA#, 30)
	position camera cX#, cY#, cZ#
	point camera 0, 0, 0

	` Update object orientation
	point object 1, camera position x(), camera position y(), camera position z()

	sync
loop

What do you think? I'm pretty stumped as to why it's not working.

Btw, I'm using DarkBASIC classic trial, and I did some forum searches, and it seems other people have this same problem, but none of the solutions offered seem to work, so I'm asking here.

Any ideas?

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Lost in Thought

20

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Joined: 4th Feb 2004

Location: U.S.A. : Douglas, Georgia

Posted: 15th Oct 2005 10:42

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When using make object plain add an extra ,1 at the end to make a proper plain.

make object plain 1, 15, 15, 1

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TDK

Retired Moderator

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Joined: 19th Nov 2002

Location: UK

Posted: 15th Oct 2005 21:08

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Quote: "make object plain 1, 15, 15, 1"

The extra 1 parameter only applies to DB Pro. It will error if you use it in the trial version of DB Classic.

TDK_Man

DB Tutorials, Hints & Tips, Utils and lots more...
A New IDE For DB Classic!

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Lost in Thought

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Joined: 4th Feb 2004

Location: U.S.A. : Douglas, Georgia

Posted: 15th Oct 2005 22:26

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Ah didn't see the classic. Well if Classic has the same bug DBP had before 5.9 then you can use this:

` Update object orientation
point object 1, camera position x(), camera position y(), camera position z()
yrotate object 1, wrapvalue(object angle y(1)+180)

as the plains are build backwards.

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Grossman

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Joined: 8th Oct 2005

Location: Russia

Posted: 16th Oct 2005 18:52

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Maybe, set object rotation zyx <obj> will helps a bit

?

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gbark

18

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Joined: 14th Oct 2005

Location: US - Virginia

Posted: 16th Oct 2005 19:31

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Thanks, using ZYX rotation, and setting the X and Y rotations after the point command, I was able to get it working.

sync on
sync rate 40
backdrop on
color backdrop rgb(32, 32, 32)

` Load texture
remstart
load bitmap "..\CrystalCatcher\BmpSparkle.bmp", 1
set current bitmap 1

get image 1, 0, 0, 45, 45
mirror bitmap 1
get image 2, 0, 0, 45, 45

set current bitmap 0
delete bitmap 1
remend

` Make object for camera to look at
make object plain 1, 15, 15
position object 1, 0, 0, 0
set object 1, 1, 0, 1, 1, 0, 0, 0
`texture object 1, 1

` Default camera position
camA# = 0
cX# = newxvalue(0, camA#, 30)
cY# = newyvalue(0, camA#, 30)
cZ# = newzvalue(0, camA#, 30)
position camera cX#, cY#, cZ#
point camera 0, 0, 0

do
	` Update camera position
	camA# = wrapvalue(camA# + 1)
	cX# = newxvalue(0, camA#, 30)
	cY# = newyvalue(0, camA#, 30)
	cZ# = newzvalue(0, camA#, 30)
	position camera cX#, cY#, cZ#
	point camera 0, 0, 0

` Update object orientation
	set object rotation zyx 1
	point object 1, camera position x(), camera position y(), camera position z()
	xrotate object 1, camera angle x()
	yrotate object 1, wrapvalue(object angle y(1)+180)

sync
loop

+ Code Snippet

sync on
sync rate 40
backdrop on
color backdrop rgb(32, 32, 32)

` Load texture
remstart
load bitmap "..\CrystalCatcher\BmpSparkle.bmp", 1
set current bitmap 1

get image 1, 0, 0, 45, 45
mirror bitmap 1
get image 2, 0, 0, 45, 45

set current bitmap 0
delete bitmap 1
remend

` Make object for camera to look at
make object plain 1, 15, 15
position object 1, 0, 0, 0
set object 1, 1, 0, 1, 1, 0, 0, 0
`texture object 1, 1

` Default camera position
camA# = 0
cX# = newxvalue(0, camA#, 30)
cY# = newyvalue(0, camA#, 30)
cZ# = newzvalue(0, camA#, 30)
position camera cX#, cY#, cZ#
point camera 0, 0, 0

do
	` Update camera position
	camA# = wrapvalue(camA# + 1)
	cX# = newxvalue(0, camA#, 30)
	cY# = newyvalue(0, camA#, 30)
	cZ# = newzvalue(0, camA#, 30)
	position camera cX#, cY#, cZ#
	point camera 0, 0, 0

	` Update object orientation
	set object rotation zyx 1
	point object 1, camera position x(), camera position y(), camera position z()
	xrotate object 1, camera angle x()
	yrotate object 1, wrapvalue(object angle y(1)+180)

	sync
loop

Thanks for all the help everybody.

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