Penrose Snowflake
/**
* Penrose Snowflake L-System
* by Geraldine Sarmiento.
*
* This example was based on Patrick Dwyer's L-System class.
*/
class LSystem {
public:
int steps = 0;
std::string axiom;
std::string rule;
std::string production;
float startLength;
float drawLength;
float theta;
int generations;
LSystem() {
axiom = "F";
rule = "F+F-F";
startLength = 90.0;
theta = radians(120.0);
reset();
}
void reset() {
production = axiom;
drawLength = startLength;
generations = 0;
}
int getAge() {
return generations;
}
void render() {
translate(width / 2, height / 2);
steps += 5;
if (steps > (int)production.length()) {
steps = production.length();
}
for (int i = 0; i < steps; i++) {
char step = production[i];
if (step == 'F') {
rect(0, 0, -drawLength, -drawLength);
noFill();
translate(0, -drawLength);
} else if (step == '+') {
rotate(theta);
} else if (step == '-') {
rotate(-theta);
} else if (step == '[') {
pushMatrix();
} else if (step == ']') {
popMatrix();
}
}
}
void simulate(int gen) {
while (getAge() < gen) {
production = iterate(production, rule);
}
}
virtual std::string iterate(std::string prod_, std::string rule_) {
drawLength = drawLength * 0.6;
generations++;
std::string newProduction = prod_;
std::string result = "";
for (int i = 0; i < (int)newProduction.size(); i++) {
if (newProduction[i] == 'F') result += rule_;
else result += newProduction[i];
}
return result;
}
virtual ~LSystem() {}
};
class PenroseSnowflakeLSystem : public LSystem {
public:
std::string ruleF;
PenroseSnowflakeLSystem() {
axiom = "F3-F3-F3-F3-F";
ruleF = "F3-F3-F45-F++F3-F";
startLength = 450.0;
theta = radians(18);
reset();
}
void useRule(std::string r_) { rule = r_; }
void useAxiom(std::string a_) { axiom = a_; }
void useLength(float l_) { startLength = l_; }
void useTheta(float t_) { theta = radians(t_); }
void reset() {
production = axiom;
drawLength = startLength;
generations = 0;
}
int getAge() {
return generations;
}
void render() {
translate(width, height);
int repeats = 1;
steps += 3;
if (steps > (int)production.length()) {
steps = production.length();
}
for (int i = 0; i < steps; i++) {
char step = production[i];
if (step == 'F') {
for (int j = 0; j < repeats; j++) {
line(0, 0, 0, -drawLength);
translate(0, -drawLength);
}
repeats = 1;
} else if (step == '+') {
for (int j = 0; j < repeats; j++) {
rotate(theta);
}
repeats = 1;
} else if (step == '-') {
for (int j = 0; j < repeats; j++) {
rotate(-theta);
}
repeats = 1;
} else if (step == '[') {
pushMatrix();
} else if (step == ']') {
popMatrix();
} else if (step >= 48 && step <= 57) {
repeats += step - 48;
}
}
}
std::string iterate(std::string prod_, std::string rule_) override {
std::string newProduction = "";
for (int i = 0; i < (int)prod_.size(); i++) {
char step = prod_[i];
if (step == 'F') {
newProduction += ruleF;
} else {
newProduction += step;
}
}
drawLength = drawLength * 0.4;
generations++;
return newProduction;
}
};
PenroseSnowflakeLSystem ps;
void setup() {
size(640, 360);
stroke(255);
noFill();
ps = PenroseSnowflakeLSystem();
ps.simulate(4);
}
void draw() {
background(0);
ps.render();
}