Calculating angle

[Rideg]

Hello, I've recently tried to work on my old project. It's a mouse operated artillery that calculates the angle the barrel should have to hit a target at the mouse's x-coord. It's not entire correctly and I don't know how to fix this.

Code: Select all

(e)=>{
    app.mousepos(0) > 66.7 ? {
        scene.my.calc1 = scene.my.g * (scene.my.d - scene.my.h) * scene.my.vel ^ 2 * app.mousepos(0) ^ 2 + scene.my.vel ^ 4 * (2 * (scene.my.d - scene.my.h) ^ 2 + app.mousepos(0) ^ 2);
        scene.my.vel ^ 6 * (-2 * scene.my.g * scene.my.d + 2 * scene.my.g * scene.my.h + scene.my.vel ^ 2) * app.mousepos(0) ^ 4 > scene.my.g ^ 2 * scene.my.vel ^ 4 * app.mousepos(0) ^ 6 ? {scene.my.calc2 = scene.my.vel ^ 6 * (-2 * scene.my.g * scene.my.d + 2 * scene.my.g * scene.my.h + scene.my.vel ^ 2) * app.mousepos(0) ^ 4 - scene.my.g ^ 2 * scene.my.vel ^ 4 * app.mousepos(0) ^ 6} : {scene.my.calc2 = 0};
        scene.my.calc2 = scene.my.calc2 ^ (0.5);
        scene.my.calc3 = scene.my.vel ^ 4 * ((scene.my.d - scene.my.h) ^ 2 + app.mousepos(0) ^ 2);
        app.mousepos(0) >= 1 ? {scene.my.angle = math.acos(((scene.my.calc1 + scene.my.calc2) / scene.my.calc3) ^ 0.5 / 2 ^ 0.5)} : {};
        scene.my.angle2 = math.asin(e.normal(1));
        scene.my.angle >= (math.pi / 2 - 0.1) ? {scene.my.angle = (math.pi / 2 - 0.1)} : {};
        scene.my.raddiff = scene.my.angle - scene.my.angle2
    } : {}
}

Please help me out. If you have any questions please tell me if I need to translate any variable.

[Mr_Stabby]

way overcomplicated, remember functions from 10th/11th grade? never thought you'd have a "real world" application for them eh all you need is take a few shots, mark up angle/bullet distance and produce a y=f(x)

[Rideg]

Could you motivate it a little maybe give me some kind of script to work on. Thank you

[Kilinich]

Just pick code from my robin hood scene.

[KarateBrot]

But make sure to turn off air friction. Otherwise it will get overcomplicated to calculate the exact angle. I know because I made an (buggy and not very advanced) artillery computer for enabled air friction.

[Rideg]

Yeas ofcourse I've turned the airfriction off. I just don't know what I've done wrong

[KarateBrot]

If you only want to hit the mouse's x-coordinate this formula is alright:
http://en.wikipedia.org/wiki/Trajectory

Code: Select all

scene.my.angle = 0.5*math.asin(sim.gravitystrength*(app.mousepos(0)-"artillery pos")/"your desired initial bullet velocity"^2)


And that's it. You don't need anything else for the target angle.

[Rideg]

artilleryPos - is that the point were it turns or were the bullet spawns?

[KarateBrot]

where the bullet spawns. sorry should have made it clearer

[Rideg]

Hmm it work in a way but it doesn't hit at the XPos(mouse).

[KarateBrot]

where does it hit then?

[Rideg]

at first it hits ahead of the xpos, then the xpos then below the xpos

[KarateBrot]

I can't say exactly what's causing this but it sounds like it's a mechanical problem. Because if your bullets hit different spots without changing the mouse's position or any other conditions it's not the code's fault. Do you use e.normal to give the bullets their angle? If yes, it COULD be a problem of your motor that's rotating the barrel. For very long ranges even the smallest wiggle can cause big inaccurateness.

[Rideg]

no, sorry was a little tired when I wrote that. I do move the mouse but I think It has something to do with the height of the spawned bullet?

[KarateBrot]

Yes the height of the bullet spawn point is your zero-level. if you want to hit at a specific height you need a different code. but that's not that hard. i can make one.

maybe i got you wrong before. you want put the mouse to any x-pos and you want the bullet to hit at the height of any target?

[Rideg]

the would if it would hit/pass the mouse x+y pos but I don't know how to do that.

[KarateBrot]

so you want to "hit" the mouse with your bullet?

[Rideg]

yeah. But my first intetion was to hit the x cord

[itsallinyourhead]

I believe the entire equation you need is:

To hit a target at range x and altitude y when fired from (0,0) and with initial velocity v the required angle(s) of launch θ are:



Additionally, leave the air friction of the sim on, and set the airFrictionMult of the shell to 0.

Just to remember to adjust for the TRUE position of the shell's origination point. It won't be 0,0 like stated. All you need do is find the difference in x and y between the origination point and the target. That should treat the origination point like it was (0,0) and give you the relative position of the target (x, y) to the origination point of the shell.