calculations..

 BBS: Inland Empire Archive
Date: 01-03-93 (18:45)             Number: 245
From: WES GARLAND                  Refer#: NONE
  To: JOHN GALLAS                   Recvd: NO  
Subj: calculations..                 Conf: (2) Quik_Bas

======CONTINUTED FROM PREVIOUS MESSAGE======
Let d be the angle in degrees, r the angle in radians.

r = PI*d/180

And of course, that means at the top of your program you
should put CONST PI = 3.1415926536

Since you say you're using 0 degrees as straight
up, theta would be 90 minus your angle, right?

Now, to make that calculation you wanted...

InitX = 1550
InitY = 1438
Angle = 348
Dist  = 3

Rads = PI*Angle/180
Y = sin(Rads) * Dist
X = cos(Rads) * Dist


NewX = InitX + X
NewY = InitY + Y

make sense to you?

 JG> Also, lets say I'm at 500,
 JG> 500 and my friends spaceship is at 600,650.  How do I
 JG> calculate what angle (in degrees, 0 to 359) I should
 JG> face in order to go visit him?

Well, first you need to know the distance between the two
of them. By the pythagorean theorem, D^2 = (X2-X1)^2 - (Y2-
Y1)^2

Now, lets assume you're at the origin (makes calculations
easier). The angle between the X axis and the origin is
easy to calculate:

Tan @ = Y/X

where @ is the angle in rads (remember how QB does trig
calcs), Y is the the Y-coordinate of your destination, and
X is the X-coordinate of your destination.

So...

InitX = 500
InitY = 500
DestX = 600
DestY = 650

Y = DestY - InitY
X = DestX - InitX

Rads = Arctan (Y/X)
Angle = 270+(180*Rads/PI):If Angle >= 360 then Angle=Angle-360

Any questions?
Wes


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