Liberty BASIC Programmer's Encyc - GamePhysics2

<h1>2D Game Physics - Part II - Acceleration</h1>
 [[user:benjamin805]] 
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<h1>Acceleration</h1>
 In some games accelerating objects is needed to show a speed increase. In this example we see how adding a constant 
acceleration value to the speed of a missile increases the distance traveled each time the graphic screen is updated.

<pre class="lb">'Window Setup nomainwin WindowWidth=400 WindowHeight=400 open &quot;Missle Launch&quot; for graphics_nsb as #main #main,&quot;trapclose [exit]&quot; 'launch angle (0-360) angle=90 'convert angle to radians AngleInRadians=angle/57.29577951 'set missile starting values movingObject.speed=2 movingObject.acceleration=1 'constant acceleration 'starting position movingObject.x=200 movingObject.y=370 'set direction of movement by getting 'the cos and sin of the angle in radians scale.x=cos(AngleInRadians) scale.y=sin(AngleInRadians) #main,&quot;down;color red;size 5&quot; timer 100,[loop] wait [loop] 'add our constant acceleration to the speed movingObject.speed=movingObject.speed+movingObject.acceleration #main,&quot;up;goto 0 12;down;\Speed: &quot;;movingObject.speed 'increase the object velocity by multiplying our new speed by our 'scale value movingObject.velocity.x=(movingObject.speed*scale.x) movingObject.velocity.y=(movingObject.speed*scale.y) 'add our new velocity value to our current movingObject x and 'y values movingObject.x=movingObject.x+movingObject.velocity.x movingObject.y=movingObject.y-movingObject.velocity.y #main,&quot;set &quot;;movingObject.x;&quot; &quot;;movingObject.y if movingObject.y&lt;0 then timer 0 wait end if wait [exit] close #main end </pre>