Follow3
/**
* Follow 3
* based on code from Keith Peters.
*
* A segmented line follows the mouse. The relative angle from
* each segment to the next is calculated with atan2() and the
* position of the next is calculated with sin() and cos().
*/
float x[20] = {0};
float y[20] = {0};
float segLength = 18;
void dragSegment(int i, float xin, float yin);
void segment(float x, float y, float a);
void setup() {
size(640, 360);
strokeWeight(9);
stroke(255, 100);
}
void draw() {
background(0);
dragSegment(0, mouseX, mouseY);
for (int i = 0; i < (int)std::size(x) - 1; i++) {
dragSegment(i+1, x[i], y[i]);
}
}
void dragSegment(int i, float xin, float yin) {
float dx = xin - x[i];
float dy = yin - y[i];
float angle = atan2(dy, dx);
x[i] = xin - cos(angle) * segLength;
y[i] = yin - sin(angle) * segLength;
segment(x[i], y[i], angle);
}
void segment(float x, float y, float a) {
pushMatrix();
translate(x, y);
rotate(a);
line(0, 0, segLength, 0);
popMatrix();
}