Ballistic help (camera angle)

[Shidony]

Hi everyone, i'm trying to make a system just for fun but there's a thing i can't do.

I downloaded this script (https://community.multitheftauto.com/index.php?p= ... ils&id=469) but i want to edit it to make the object go in the air with the player camera angle.

I explain better, with this script, the object is throwed at the same z pos of the player, i want to throw the object in the air if i look in the sky or throw it on the ground if i look the ground but i don't know how to get the camera angle.

Can you help me ?

Thanks in advance,

Cordialy.

[50p]

I'm trying to think what you actually want to do.. I can't really think of the "camera angle" you're thinking about.

[Shidony]

See this image: http://upload.wikimedia.org/wikipedia/c ... stique.jpg

I'm trying to search the ϴ angle. Imagine that the canon is a player.

[guix]

Hello,

Using getCameraMatrix, you have the direction vector of where the player is looking

[Shidony]

Yes i know this function but i don't know how to calcul the angle with the coords i get.

[guix]

You can do it with function atan2

Ok it's not easy when you don't know where to start, so here is a little example:

function getAnglesBetweenPoints3D( x1, y1, z1, x2, y2, z2 ) 
  
    x1 = x2 - x1 
    y1 = y2 - y1 
     
    x2 = math.atan2( x1, y1 ) * 57.29578 
    y2 = math.atan2( z2 - z1, math.sqrt( (x1 * x1) + (y1 * y1) ) ) * 57.29578 
     
    return x2, y2 
     
end 
  
  
function displayAngles() 
     
    local x1, y1, z1, x2, y2, z2 = getCameraMatrix( localPlayer ) 
    local a1, a2 = getAnglesBetweenPoints3D( x1, y1, z1, x2, y2, z2 ) 
  
    outputChatBox( string.format( "a1 = %.2f   a2 = %.2f", a1, a2 ) ) 
  
end 
addEventHandler( "onClientRender", root, displayAngles ) 

The angle you asked is a2, but you will need a1 as well isn't it?

Edited March 6, 2013 by Guest

[Shidony]

I didn't saw you edited your post, i don't understand why you're using cx1, cy1 etc ... but i found this function:

local function getCameraRotation() 
    local px, py, pz, lx, ly, lz = getCameraMatrix() 
    local rotz = 6.2831853071796 - math.atan2 ( ( lx - px ), ( ly - py ) ) % 6.2831853071796 
    local rotx = math.atan2 ( lz - pz, getDistanceBetweenPoints2D ( lx, ly, px, py ) ) 
    --Convert to degrees 
    rotx = math.deg(rotx) 
    rotz = -math.deg(rotz) 
    return rotx, 180, rotz 
end 

I teste it and it works but know, i need to find the velocity, i allready have the velocity for x and y but fox z a cannot find the calculation to make the object go into the air and then, fall to the ground with a gravity.

EDIT: found the solution, i do not have to convert the rotx into degrees. thanks for your help .

[guix]

Obviously it was a mistake.

[Shidony]

This is what i was thinking ^^.

So now, i have done my system correctly but the objects hich doesn't have a mass, doesn't fall to the ground, i'm trying to make a virtual gravity but how ?

[50p]

If you got them shoot at the right angle then simply decrease its Z coord to make a fake gravity look.

[Shidony]

That's what i wanted to do but what solution do you think is better, make another setElementVelocity or a moveObject ?

[50p]

You could use setElementVelocity with lower velocity. Doesn't setElementVelocity simulate physics/gravity?

[Shidony]

I allready use setElementVelocity to throw my object in the air, but not all objects get back to the ground, i tested it with a basket ball, it fall to the ground, but a computer doesn't.

[50p]

There was a function https://wiki.multitheftauto.com/wiki/IsObjectStatic but I'm not sure if it still works with newer MTA. Anyway, if object has some gravity properties then it will react to gravity otherwise you will have to script it yourself. To make smooth movement you'll need to use onClientRender and roughly calculate current frame position based on velocity and use setElementPosition instead of setElementVelocity.

[Shidony]

Thanks, i'll try to do that