código de examen

/**

* Recursive Tree

* by Daniel Shiffman.

*

* Renders a simple tree-like structure via recursion.

* The branching angle is calculated as a function of

* the horizontal mouse location. Move the mouse left

* and right to change the angle.

*/

float theta;

void setup() {

size(640, 360);

smooth();

}

void draw() {

background(0);

frameRate(30);

stroke(255);

// Let's pick an angle 0 to 90 degrees based on the mouse position

float a = (mouseX / (float) width) * 90f;

// Convert it to radians

theta = radians(a);

// Start the tree from the bottom of the screen

translate(width/2,height);

// Draw a line 120 pixels

line(0,0,0,-120);

// Move to the end of that line

translate(0,-120);

// Start the recursive branching!

branch(120);

}

void branch(float h) {

// Each branch will be 2/3rds the size of the previous one

h *= 0.66;

// All recursive functions must have an exit condition!!!!

// Here, ours is when the length of the branch is 2 pixels or less

if (h > 2) {

pushMatrix(); // Save the current state of transformation (i.e. where are we now)

rotate(theta); // Rotate by theta

line(0, 0, 0, -h); // Draw the branch

translate(0, -h); // Move to the end of the branch

branch(h); // Ok, now call myself to draw two new branches!!

popMatrix(); // Whenever we get back here, we "pop" in order to restore the previous matrix state

// Repeat the same thing, only branch off to the "left" this time!

pushMatrix();

rotate(-theta);

line(0, 0, 0, -h);

translate(0, -h);

branch(h);

popMatrix();

}

}