Pattern Generator

In this project, we will create an interactive pattern generator that displays four different artistic patterns. Click the mouse to cycle through beautiful designs including flowers, stars, houses, and trees - all drawn with code!

Sketch

int pattern = 0;

void setup() {
    size(400, 400);
}

void draw() {
    background(50);

    // Display current pattern hint
    fill(255);
    textSize(16);
    text("Click to switch pattern: " + getPatternName(), 10, 30);

    if (pattern == 0) drawFlower();
    else if (pattern == 1) drawStar();
    else if (pattern == 2) drawHouse();
    else drawTree();
}

void mousePressed() {
    pattern = (pattern + 1) % 4;
}

// Get pattern name
String getPatternName() {
    if (pattern == 0) return "Flower";
    else if (pattern == 1) return "Star";
    else if (pattern == 2) return "House";
    else return "Tree";
}

// Draw flower
void drawFlower() {
    pushMatrix();
    translate(200, 200);

    // Petals
    fill(255, 100, 150);
    noStroke();
    for (int i = 0; i < 8; i++) {
        pushMatrix();
        rotate(i * PI / 4);
        ellipse(0, 40, 30, 60);
        popMatrix();
    }

    // Center
    fill(255, 255, 0);
    ellipse(0, 0, 40, 40);

    // Stem
    fill(50, 200, 50);
    rect(-5, 0, 10, 100);

    // Leaves
    fill(100, 255, 100);
    ellipse(-20, 60, 25, 15);
    ellipse(20, 80, 25, 15);

    popMatrix();
}

// Draw star
void drawStar() {
    pushMatrix();
    translate(200, 200);

    fill(255, 255, 100);
    stroke(255, 200, 0);
    strokeWeight(2);

    beginShape();
    for (int i = 0; i < 10; i++) {
        float angle = i * PI / 5;
        float radius = (i % 2 == 0) ? 80 : 40;
        float x = cos(angle - PI / 2) * radius;
        float y = sin(angle - PI / 2) * radius;
        vertex(x, y);
    }
    endShape(CLOSE);

    // Star twinkle effect
    fill(255, 255, 255, 150);
    noStroke();
    ellipse(0, 0, 20, 20);

    popMatrix();
}

// Draw house
void drawHouse() {
    pushMatrix();
    translate(200, 250);

    // House body
    fill(200, 150, 100);
    stroke(150, 100, 50);
    strokeWeight(2);
    rect(-80, -60, 160, 120);

    // Roof
    fill(150, 50, 50);
    triangle(-90, -60, 0, -120, 90, -60);

    // Door
    fill(100, 50, 0);
    rect(-20, -10, 40, 70);

    // Door knob
    fill(255, 255, 0);
    ellipse(10, 20, 6, 6);

    // Windows
    fill(150, 200, 255);
    rect(-60, -40, 30, 25);
    rect(30, -40, 30, 25);

    // Window frames
    stroke(100);
    strokeWeight(1);
    line(-45, -40, -45, -15);
    line(-60, -27.5, -30, -27.5);
    line(45, -40, 45, -15);
    line(30, -27.5, 60, -27.5);

    // Chimney
    fill(100, 100, 100);
    rect(40, -110, 20, 40);

    // Smoke
    fill(200, 200, 200, 100);
    ellipse(55, -120, 15, 10);
    ellipse(60, -130, 12, 8);
    ellipse(65, -140, 10, 6);

    popMatrix();
}

// Draw tree
void drawTree() {
    pushMatrix();
    translate(200, 350);

    // Trunk
    fill(101, 67, 33);
    stroke(80, 50, 20);
    strokeWeight(2);
    rect(-15, -80, 30, 80);

    // Crown – multiple green circles
    noStroke();
    fill(34, 139, 34);
    ellipse(0, -120, 120, 80);

    fill(50, 160, 50);
    ellipse(-20, -100, 80, 60);

    fill(60, 180, 60);
    ellipse(20, -110, 90, 70);

    fill(40, 120, 40);
    ellipse(0, -90, 100, 50);

    // Leaf details
    fill(80, 200, 80);
    for (int i = 0; i < 8; i++) {
        float x = random(-50, 50);
        float y = random(-140, -80);
        ellipse(x, y, random(10, 20), random(8, 15));
    }

    // Apples (random positions)
    fill(255, 0, 0);
    ellipse(-25, -105, 8, 8);
    ellipse(15, -125, 8, 8);
    ellipse(30, -95, 8, 8);

    popMatrix();
}

How it works?

This pattern generator demonstrates several important programming concepts:

State Management: - The pattern variable keeps track of which design to display (0-3) - mousePressed() function cycles through patterns using modulo operator: (pattern + 1) % 4

Modular Code Design: - Each pattern has its own function: drawFlower(), drawStar(), drawHouse(), drawTree() - The main draw() function uses conditional statements to choose which pattern to display - getPatternName() function provides user-friendly pattern names

Advanced Drawing Techniques: - Matrix transformations: pushMatrix() and popMatrix() save and restore coordinate systems - Translation: translate() moves the origin point for easier drawing - Rotation: rotate() creates symmetrical patterns (like flower petals) - Loops: for loops create repeated elements efficiently

Visual Effects: - Color gradients: Different fill() colors create depth and realism - Transparency: Alpha values create semi-transparent effects (like smoke) - Layering: Multiple shapes build complex designs - Random elements: random() adds natural variation to tree leaves

Key Functions Used: - ellipse(), rect(), triangle() for basic shapes - beginShape() and vertex() for custom star shape - stroke() and strokeWeight() for outlines - line() for details like window frames

Interactive Features: - Click anywhere to see the next pattern - Pattern name displays at the top - Smooth transitions between different artistic styles

This project shows how code can create beautiful art while teaching fundamental programming concepts!

For more please refer to Processing Reference.