OpenEuphoria

Re: setPixel

• Posted by Brian Broker <bkb at CNW.COM> Feb 03, 2000
• 388 views

Plotting the path of a projectile...  I will give you some psuedocode so as
not to take the fun out of your programming experience.

variables:

v = initial velocity
a = initial angle from horizon

vx = initial velocity in x direction
vy = initial velocity in y direction

t = time
g = gravity ( tweak this value for whatever looks best )

vx = v * cos( a ) = a constant value (assuming no friction/wind)
vy = v * sin( a ) - g*t

as time (t) advances from zero, your object will be at:

x = v * cos( a ) * t
y = v * sin( a ) * t + g*t*t / 2


use the above equations to plot points as long as they are on the screen:

t = 0
x = initial x value
y = initial y value
while (x < MAX_X ) and (y < MAX_Y ) do
  x = v * cos( a ) * t
  y = v * sin( a ) * t + g*t*t / 2
  plot( x, y )
  t = t + 1  --(or t = t + time_increment)
end while


Keep in mind that Euphoria trig functions expect values in radians, not
degrees.  To convert from degrees to radians, use:

r = d * PI / 180

where r = value in radians and d = value in degrees

hope this helps!
-- Brian