atan2()

Category: Math

Subcategory: Trigonometry

Complexity: Intermediate

Description

Calculates the angle (in radians) from a specified point to the coordinate origin as measured from the positive x-axis. Values are returned as a float in the range from PI to -PI. The atan2() function is most often used for orienting geometry to the position of the cursor. Note: The y-coordinate of the point is the first parameter, and the x-coordinate is the second parameter, due the the structure of calculating the tangent.

tan()

Example

Code:

Copy

void draw() {
  background(204);
  translate(width/2, height/2);
  float a = atan2(mouseY-height/2, mouseX-width/2);
  rotate(a);
  rect(-30, -5, 60, 10);
}