Reach3
/**
* Reach 3
* based on code from Keith Peters.
*
* The arm follows the position of the ball by
* calculating the angles with atan2().
*/
const int numSegments = 8;
float x[numSegments] = {0};
float y[numSegments] = {0};
float angle[numSegments] = {0};
float segLength = 26;
float targetX, targetY;
float ballX = 50;
float ballY = 50;
int ballXDirection = 1;
int ballYDirection = -1;
void positionSegment(int a, int b);
void reachSegment(int i, float xin, float yin);
void segment(float x, float y, float a, float sw);
void setup() {
size(640, 360);
strokeWeight(20.0);
stroke(255, 100);
noFill();
x[(int)std::size(x)-1] = width/2; // Set base x-coordinate
y[(int)std::size(x)-1] = height; // Set base y-coordinate
}
void draw() {
background(0);
strokeWeight(20);
ballX = ballX + 1.0 * ballXDirection;
ballY = ballY + 0.8 * ballYDirection;
if (ballX > width-25 || ballX < 25) {
ballXDirection *= -1;
}
if (ballY > height-25 || ballY < 25) {
ballYDirection *= -1;
}
ellipse(ballX, ballY, 30, 30);
reachSegment(0, ballX, ballY);
for (int i = 1; i < numSegments; i++) {
reachSegment(i, targetX, targetY);
}
for (int i = (int)std::size(x)-1; i >= 1; i--) {
positionSegment(i, i-1);
}
for (int i = 0; i < (int)std::size(x); i++) {
segment(x[i], y[i], angle[i], (i+1)*2);
}
}
void positionSegment(int a, int b) {
x[b] = x[a] + cos(angle[a]) * segLength;
y[b] = y[a] + sin(angle[a]) * segLength;
}
void reachSegment(int i, float xin, float yin) {
float dx = xin - x[i];
float dy = yin - y[i];
angle[i] = atan2(dy, dx);
targetX = xin - cos(angle[i]) * segLength;
targetY = yin - sin(angle[i]) * segLength;
}
void segment(float x, float y, float a, float sw) {
strokeWeight(sw);
pushMatrix();
translate(x, y);
rotate(a);
line(0, 0, segLength, 0);
popMatrix();
}