Rotate objects around 1 point

[eldinhelja]

Hello, I've had a long day. My brain is not working.

I have created this :

I have 8 objects called P1, P2, P3...
I Want to rotate every point at once for some angle "degRotate"

//Variables
degRotate=240

//Find Center
CenterX = (x1+x2)/2
CenterY = (y1+y2)/2

//Get Radius
radius = point_distance(x1, y1, CenterX, CenterY)

//Create points after rotation
p[0] = instance_create(....) //p[0] is P1 (Point 1)

So eg. if I rotate it by 30 deg. I need to get this :

I am really tired.

EDIT :

Forgot to mention : p[0] = instance_create(x1,y1,x2,y2) //Should look like thise

Just need a formula, not code

 

[Nux]

You're going to have to get the vector of each object from the main object's origin, the longitudinal and lateral components.

From there you can use trigonometric functions to calculate where the objects will be when turned θ degrees about a central point (the centre of your main object).
Alternatively, you are able to use length_dir_*.

I might dump some code i've done with this before to help better explain.

EDIT: Alrighty! General formulae using trigonometric functions:

    x = xCentre + xComponent*cos(θ) + yComponent*sin(θ)
    y = yCentre + xComponent*cos(θ+90) + yComponent*sin(θ+90)

EDIT#2: I will add: xComponent and yComponent are not coordinates within the room; they are Δx and Δy when θ = 0 degrees (has no rotation).

If each point has an equal spacing of 20 in the x direction, and 40 in the y direction, the x and y component of the 'p1' will be:

    xComponent = xCentre - (20*3)*0.5  // this is because there are 3 separations between the points on the x-axis
    yComponent = yCentre - (40*1)*0.5  // *1 because there is only 1 separation between two points along the y-axis

I'm sure you can extrapolate this or find exact relative points for each point of yours with a bit of tweaking.

 

[eldinhelja]

@Nux thank you ! I will try it tomorrow.

When theta is 0 degrees I know coordinates of all points, but I dont understand what are x and y components.

 

[Nux]

coordinates of all points, but I dont understand what are x and y components.

Ohh right! That's great; it simplifies things a lot more.
the components is the x and y distance from the centre object



So to get each component, just take away a point's xy coordinates from the centre object's xy coordinates, and store the x and y values seperately.

 

[eldinhelja]

I got it working using this code :

repeat(7) {
            radius=abs(point_distance(pSec[i].x, pSec[i].y, centerX, centerY)) //Radius Between the current point and the center
            newAngle=(deg*30)+point_direction(pSec[i].x, pSec[i].y, centerX, centerY);
                      //show_message("Radius between " + string(pSec[i].x) + ", " + string(pSec[i].y) + " and " + string(centerX) + ", " + string(centerY) + " is = " + string(radius));
            pSec[i].x = centerX+cos((pi/180)*newAngle)*radius;
            pSec[i].y = centerY+sin((pi/180)*newAngle)*radius;
            i++;
        }

This is my idea :

And I turn them one by one by some angle Theta.

@Nux Thanks for support!