When the shape hits the edge of the window, it reverses its direction.
int rad = 60; // Width of the shape float xpos, ypos; // Starting position of shape float xspeed = 2.8; // Speed of the shape float yspeed = 2.2; // Speed of the shape int xdirection = 1; // Left or Right int ydirection = 1; // Top to Bottom void setup() { size(640, 360); noStroke(); frameRate(30); ellipseMode(RADIUS); // Set the starting position of the shape xpos = width/2; ypos = height/2; } void draw() { background(102); // Update the position of the shape xpos = xpos + ( xspeed * xdirection ); ypos = ypos + ( yspeed * ydirection ); // Test to see if the shape exceeds the boundaries of the screen // If it does, reverse its direction by multiplying by -1 if (xpos > width-rad || xpos < rad) { xdirection *= -1; } if (ypos > height-rad || ypos < rad) { ydirection *= -1; } // Draw the shape ellipse(xpos, ypos, rad, rad); }
该运动时匀速直线运动。