help with 180 degrea arc movement please

[micky4fun]

Hi all

was wondering if someone with more maths know how than me , proberly quite simple

i want to move the blue box along the red curve , keeping the same distance from the center dot , by moving the mouse along its x axis
ie using mousex() command , can anyone show me how

thanks
mick

[kevin]

PlayBASIC Code: [Select]

   do
      Cls 0
   
      mx#=MouseX()

      // Convert X# to scaler (Inverted)
      XScaler# = (GetScreenWidth()-mX#)/GetScreenWidth()

      // size of arc
      Radius =100

      // get angle    
      Angle#=180*xScaler#

      // get screen pos      
      X#=400+cos(angle#)*Radius
      Y#=300+sin(angle#)*Radius

      // draw the circle to present the arc
      circlec 400,300,radius,false,rgb(255,0,0)


      // draw line between object and center
      linec x#,y#,400,300,rgb(255,255,0)

      // draw object on path
      circlec x#,y#,5,true,rgb(0,0,255)


      Sync
   loop

[micky4fun]

Hi Kevin

Thanks for the code snippet , took you about 10 seconds to sort out , i do and try and have ago myself for a few hours before posting any questions
but this is just beyond me ,
wonder if you can go a little further with this and get the blue box to move along the yellow line with using the mousey() command , so it moves up
and down the yellow line when the mouse moves up and down ,

thanks
mick :)

[kevin]

To move along the hypot,  the Y value is being inpretered as the circles radius.  So take the mouse's Y position, then dividie it by the screen height.   This gives you a scaler between 0.0 and 1.0.     Mult this scaler by the radius, job done..

[stevmjon]

to micky4fun

since you are having some trouble understanding this, i have used kev's code above, to give an example.

i have explained it as best i can. i hope it helps.

  stevmjon

p.s. i hope i haven't made it more confusing...lol

[micky4fun]

Hi stevmjon

Thanks for posting the code for kevin explanation , thats just what i was looking for , nice of you to explain it in code
lucky you guys know what you are doing , i was never taught this at school
and would have took me hours to suss out , if i ever did that is.

thanks
mick