How do you free rotate an object with Vectorscript

[WhoCanDo]

I want to create an object:

repeat

if (MouseDown(x1, y1)) then

begin

moveto(x1, y1);

x2 := x1 + 580;

y2 := y1;

closepoly;

poly (30,#90,x2,#0,30,#-90);

h := lnewobj;

end;

until (h <> Nil);

and after h := lnewobj; I want to pick the object and free rotate it with the mouse around x1,y1 until I pick a second point with the mouse.

I've tried

repeat

getmouse (x3, y3);

rotatepoint (x1, y1, AngleOfRotation);

redraw;

until (MouseDown (x3, y3));

but I think I am on the wrong track.

Any suggestions please?

[MullinRJ]

Hi Who,

???You're definitely on the right track. However, you need to calculate the angle you want to rotate from points 1 and 3 before you call the RotatePoint() function. This is most easily done with vector function Vec2Ang(). Since point 1 is the center of interest (and rotation) subtract it from point 3 and stuff it into vector V as follows:

V.x := x3 - x1;

V.y := y3 - y1;

AngleOfPt3 := Vec2Ang(V);???{ relative to point 1 }

The following script is not what you want, but it executes in a humorous way. Try it.

PROCEDURE yyy;
VAR
H :Handle;
x1, y1, x2, y2, x3, y3, AngleOfPt3 :Real;
V :Vector;
BEGIN
repeat
	if (MouseDown(x1, y1)) then begin
		moveto(x1, y1);
		x2 := x1 + 580;
		y2 := y1;
		closepoly;
		poly (30,#90,x2,#0,30,#-90);
		H := lnewobj;
	end;
until (H <> Nil);

repeat
	getmouse (x3, y3);

	V.x := x3 - x1;
	V.y := y3 - y1;
	AngleOfPt3 := Vec2Ang(V);

	RotatePoint (x1, y1, AngleOfPt3);

	redraw;
until (MouseDown (x3, y3));
END;
Run(yyy);

Since you are in a loop, each time through you will rotate your object again, so your script has to remember how much it rotated the object the last time through and subtract that off for the current pass through the loop. This example should be more to your liking.

PROCEDURE xxx;
VAR
H :Handle;
x1, y1, x2, y2, x3, y3 :Real;
AngleOfPt3, lastPt3Ang :Real;
V :Vector;

BEGIN
repeat
	if (MouseDown(x1, y1)) then begin
		moveto(x1, y1);
		x2 := x1 + 580;
		y2 := y1;
		closepoly;
		poly (30,#90,x2,#0,30,#-90);
		H := lnewobj;
	end;
until (H <> Nil);

lastPt3Ang := 0;
repeat
	getmouse (x3, y3);

	V.x := x3 - x1;
	V.y := y3 - y1;
	AngleOfPt3 := Vec2Ang(V);

	RotatePoint (x1, y1, AngleOfPt3 - lastPt3Ang);	{ rotate by delta angle }
	lastPt3Ang := AngleOfPt3;

	redraw;
until (MouseDown (x3, y3));
END;
Run(xxx);

HTH,

Raymond

[WhoCanDo]

Thanks Raymond, I didn't know I was so close.

I've not used vectors before so I will have to study it more.

Love the first macro.

Regards

[WhoCanDo]

A little more help please.

I have replaced the first "repeat until" with a GetPt because I want to be able to pick an existing object to align this new object with.

The problem is that GetMouse turns off snapping opitons.

Is there another way to do the following?

procedure Get_Placement;

var

h1, h2 :Handle;

x1, y1, x2, y2 : real;

AngleOfPt2, LastPt2Ang : real;

V : vector;

begin

GetPt ( x1, y1);

moveto (x1, y1);

closepoly;

poly (60, #90, 580, #0, 60, #-90);

LastPt2Ang := 0;

repeat

GetMouse (x2, y2);

V.x := x2 - x1;

V.y := y2 - y1;

AngleOfPt2 := Vec2Ang (V);

RotatePoint (x1, y1, AngleOfPt2 - LastPt2Ang); { rotate by delta angle }

LastPt2Ang := AngleOfPt2;

Redraw;

until (MouseDown (x2, y2));

end;

run (Get_Placement);