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PONG expression
I got this script from further down the forum.
I am trying to make a script that is like pong. Where the ball bounces between the four sides of a box, forever. I can add the paddles after, to make it look like someone is playing the game.I got this expression off creativecow.net but it doesn’t bounce between the sides
box=[10,10,100,200]; // box you want to stay in [x1,y1,x2,y2]
motion=[312,123]; // motion-vector in pixels per sond [x,y]
startpos=[160,120]; // startposition// calculations:
w=box[2]-box[0]; h=box[3]-box[1]; corner=[box[0],box[1]];
delta=motion*time; pos=startpos+delta-corner;
xx=pos[0]%(w*2); yy=pos[1]%(h*2);corner+[xx,yy]
Anyone got a script that would bounce an between the four sides of the screen forever?
Thanks
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1 Reply
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Try this one:
left = 0;
top = 0;
right = thisComp.width;
bottom = thisComp.height;minSpeed = 200; //pixels per second
maxSpeed = 500;minX = left + 20;
maxX = right – 20;
minY = top + 20;
maxY = bottom – 20;minR = 5;
maxR = 85;seedRandom(index,true);
// calc start position
pos = random([minX,minY],[maxX,maxY])
quadrent = Math.floor(random(4))*90;
angle = random(minR,maxR) + quadrent;
spd = random(minSpeed,maxSpeed);// initialize time count;
t = 0;
while(t <= time){ rads = degreesToRadians(angle); xVel = spd*Math.cos(rads); yVel = spd*Math.sin(rads); // see if going up or down if (yVel < 0) yLim = top else yLim = bottom; // see if going right or left if (xVel < 0) xLim = left else xLim = right; timeX = (xLim - pos[0])/xVel; timeY = (yLim - pos[1])/yVel; if (timeX < timeY){ //hit left or right wall if (t + timeX >= time){
deltaT = time – t;
pos += [xVel,yVel]*deltaT;
break;
}else{
pos = [xLim,pos[1] + yVel*timeX];
angle = 180 – angle;
t += timeX;
}
}else{ //hit upper or lower wall
if (t + timeY >= time){
deltaT = time – t;
pos += [xVel,yVel]*deltaT;
break;
}else{
pos = [pos[0] + xVel*timeY,yLim];
angle = 360 – angle;
t += timeY;
}
}
}
posDan
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