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stretching sprite from point a to point b
#268481
05/29/09 14:27
05/29/09 14:27
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Joined: Jun 2006
Posts: 2,640
Earth
Germanunkol
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OP
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Joined: Jun 2006
Posts: 2,640
Earth
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Hi!
I want to create a lightning effect and I've created the sprites.
I have three problems:
-A sprite's size seems to depend on the image size (correct me if I'm wrong) so if I use vec_normalize(sprite.scale_x,vec_dist(pointA,pointB)); I get something that's way too big, cause sprite.scale_x == 1 does not mean its one quant in length.
-Orientation issues...
vec_diff(temp,pointA,pointB);
vec_to_angle(sprite.pan,temp);
won't work, because in 3d, a sprite's x axis isn't along the image's 2d x axis, instead it's perpendicular to the images x and y axis.
-origin of a sprite is its middle, so I need to move it so that the end of the sprite is at either point a or point b.
I don't want to use a model instead.
Does someone have a script that streches a sprite from any given point a to point b? I've searched, but couldn't find anything...
Thanks...
~"I never let school interfere with my education"~
-Mark Twain
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Re: stretching sprite from point a to point b
[Re: Germanunkol]
#268708
05/30/09 19:19
05/30/09 19:19
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Joined: Jun 2006
Posts: 2,640
Earth
Germanunkol
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Posts: 2,640
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there must be somewhere here who's used sprites for lightning effects? Any AUM that does it? does anyone know?
~"I never let school interfere with my education"~
-Mark Twain
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Re: stretching sprite from point a to point b
[Re: Germanunkol]
#268740
05/30/09 21:52
05/30/09 21:52
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Joined: Dec 2008
Posts: 271
Saturnus
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Posts: 271
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Hello! The following code should work for you, I think. You need to know the unscaled height of your sprite in quants to make use of it. Just substract your sprite's "min_y" property from its "max_y" property to get the height.
VECTOR vec_to;
ANGLE ang_to;
vec_diff(vec_to, pointB, pointA);
vec_to_angle(ang_to, vec_to);
// H = unscaled height of yourSprite in quants
yourSprite->scale_y = vec_length(vec_to) / H;
vec_lerp(vec_to, pointA, pointB, 0.5);
vec_set(yourSprite->x, vec_to);
yourSprite->pan = ang_to.pan;
yourSprite->tilt = ang_to.tilt + 90;
yourSprite->roll = 0;
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Re: stretching sprite from point a to point b
[Re: Saturnus]
#268871
05/31/09 15:21
05/31/09 15:21
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Joined: Jun 2006
Posts: 2,640
Earth
Germanunkol
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Posts: 2,640
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thank you very much! you.pan = ang_to.pan; you.tilt = ang_to.tilt+90; you.roll = 90; worked better for me. But the rest of your code was just what I needed! 
~"I never let school interfere with my education"~
-Mark Twain
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