Using Transformations For Billboards, I searched, I googled, and all those other things. Options

[redfeild]

I'm trying to use billboards (polygons that face the camera and appear as a flat image) for some effects in a fangame. I've got the objects to face the camera on the X and Y axis, but I'm having some trouble getting them to face the camera on the Z axis. Screens of what I'm talking about:

Smoke effect viewed from side:
http://img190.imageshack.us/img190/8755/screenshot105w.png
Looks pretty good IMO
Viewed from top:
http://img156.imageshack.us/img156/9680/screenshot106j.png
Looks like ****.

Same with ring-get effect:
Viewed from side, looks good:
http://img156.imageshack.us/img156/4610/screenshot111a.png
Viewed from top, the sparkles don't face the camera correctly:
http://img23.imageshack.us/img23/410/screenshot113y.png

Here's the code I am using for the sparkle effect currently (draw event, the smoke effect is relatively the same):

CODE

draw_set_alpha(alpha)
d3d_transform_set_identity()
d3d_transform_add_rotation_z(point_direction(x,y,camera_3rdperson.xf,camera_3rdperson.yf)) //rotates it towards the camera on the X/Y axis
d3d_transform_add_translation(x,y,z)
d3d_draw_wall(0,-r,r,0,r,-r,tex,1,1)
d3d_transform_set_identity()
draw_set_alpha(1)

I've tried several things to get it to rotate correctly, but nothing has worked so far.

Also I can't use the billboard effect from the FPS tutorial (or any similar effect that doesn't use transformations) since I plan on using this effect with certain enemies, so they point towards your character.


Any help would be greatly appreciated.

[frankpiet]

what is -r and r?

I would reccomend(for ease) to have 2 modes for each drawing. mode 1 would draw a wall while mode 2 would draw a floor at a elevated z

[redfeild]

what is -r and r?

I would reccomend(for ease) to have 2 modes for each drawing. mode 1 would draw a wall while mode 2 would draw a floor at a elevated z

r stands for radius Even though the object isn't a circle, I use that to scale it.

And I've tried that, it just made the effect look worse :\

[jsorgeagames]

This is a script I made for drawing a billboard. It uses another script, which is included.

Billboard

CODE

var x1,y1,z1;
x1=argument0
y1=argument1
z1=argument2

var x2,y2,z2;
x2=obj_camera.x
y2=obj_camera.y
z2=obj_camera.z

var dir1,dir2;
dir1=point_direction(x1,y1,x2,y2)
dir2=d3d_point_direction(x1,y1,-z1,x2,y2,-z2)

d3d_transform_set_identity()
d3d_transform_add_rotation_x(dir2)
d3d_transform_add_rotation_z(dir1-90)
d3d_transform_add_translation(x1,y1,z1)

var s; s=2;
d3d_draw_wall(-s,0,-s,s,0,s,tex,1,1)

d3d_transform_set_identity()

d3d_point_direction()

CODE

return (point_direction(0,argument2,point_distance(argument0,argument1,argument3,argument4),argument5));

Note: you may have to flip the z-axis in the code. This code was made for a camera where up on the z-axis is positive and down is negative.

This post has been edited by jsorgeagames: Nov 7 2009, 03:01 AM

[redfeild]

This is a script I made for drawing a billboard. It uses another script, which is included.

Billboard
...

d3d_point_direction()
...

Note: you may have to flip the z-axis in the code. This code was made for a camera where up on the z-axis is positive and down is negative.

Thanks, works perfect ;P The smoke effect still looks kind of...bad, due to it clipping through the floor sometimes, but it's nothing I didn't expect...and it looks way better than it did

If you want credit, I do need a way to fill the credits screen up XD

[jsorgeagames]

This is a script I made for drawing a billboard. It uses another script, which is included.
<snip>

Thanks, works perfect ;P The smoke effect still looks kind of...bad, due to it clipping through the floor sometimes, but it's nothing I didn't expect...and it looks way better than it did

If you want credit, I do need a way to fill the credits screen up XD

No, it's okay, I don't need credit. I didn't make the d3d_point_direction() script though, I got it here on the forums, but I don't remember who made it.

EDIT: As for it clipping through the floor, I thought up a method of pushing it higher, out of the floor:

CODE

var floorz; //floor z
floorz=0
var myz; //smoke z
myz=1.5
var s; //size
s=2

if myz-s<floorz
myz=floorz+s+.1

This post has been edited by jsorgeagames: Nov 8 2009, 09:07 PM