前言
最近在上《优秀科普纪录片》时,看了一部有关 分形 的纪录片,在观看的过程中,想着自己也来生成一些分形图片,正好偶然了解到了SFML这个简单的图形库,所以天时地利人和,正好查一些资料来学习一下。
以下代码都是使用到SFML库的C++代码,所以如果要尝试使用的话,首先要配置好环境(我上一篇有介绍Cmake的配置方式,可以参考)
三分线段
看图就明白了吧。。
#include <iostream>
#include <cmath>
#include <SFML/Graphics.hpp>using namespace std;sf::RenderWindow window(sf::VideoMode(1920,1080), "Tree");
float base = 100;
void getNextLine(float ax, float ay, float bx, float by, float len){if(len < 0.1f)return;float cx, cy, dx, dy, newLen;newLen = len / 3.0;cx = ax + newLen; cy = ay + base;dx = bx - newLen; dy = by + base;getNextLine(ax, ay + base, cx, cy, newLen);getNextLine(dx, dy, bx, by + base, newLen);sf::Vertex line[] = {sf::Vertex(sf::Vector2f(ax, ay), sf::Color::Cyan),sf::Vertex(sf::Vector2f(bx, by), sf::Color::Cyan)};window.draw(line, 2, sf::Lines);return;
}int main(){window.clear();getNextLine(300, 300, 1600, 300, 1300);window.display();sf::Event event;while (window.isOpen()){while (window.pollEvent(event)){if (event.type == sf::Event::Closed) window.close();}}return 0;
}
分形树 FractralTree
这个生成的方式很简单,就是每次对一条线段取 2 3 \frac{2}{3} 32 然后对角度 + 60 和 − 30 +60和-30 +60和−30 来的到下一个线段的位置,不断地递归下去即可。
#include <iostream>
#include <cmath>
#include <SFML/Graphics.hpp>using namespace std;sf::RenderWindow window(sf::VideoMode(1920,1080), "Tree");void start(float inix, float iniy, float degree, float length)
{if (length < 1.0f) return;else{float newlength=0.67f * length;float finx = inix + (newlength * (float)cos(degree * (3.14 / 180.0f)));float finy = iniy + (newlength * (float)sin(degree * (3.14 / 180.0f)));sf::Vertex line[]= {sf::Vertex(sf::Vector2f(inix, iniy)),sf::Vertex(sf::Vector2f(finx, finy))};start(finx, finy, degree+60.0f, newlength);start(finx, finy, degree-30.0f, newlength);window.draw(line, 2, sf::Lines);//line.setFillColor(sf::Color::Blue);//window.display(); // Uncomment for animation}
}int main()
{window.clear();start(1000, 799, -90, 350);window.display();sf::Event event;while (window.isOpen()){while (window.pollEvent(event)){if (event.type == sf::Event::Closed) window.close();}}return 0;
}
Koch雪花
#include <iostream>
#include <cmath>
#include <SFML/Graphics.hpp>
const double pi = 3.1415926;
using namespace std;sf::RenderWindow window(sf::VideoMode(1920,1080), "Tree");
float base = 100;
void getNextLine(float ax, float ay, float bx, float by){float len = sqrt((ax - bx) * (ax - bx) + (ay - by) * (ay - by));if(len < 1.0f){sf::Vertex line[] = {sf::Vertex(sf::Vector2f(ax, 1200 - ay), sf::Color::Cyan),sf::Vertex(sf::Vector2f(bx, 1200 - by), sf::Color::Cyan)};window.draw(line, 2, sf::Lines);return; }float cx, cy, dx, dy, ex, ey, newLen;newLen = len / 3.0;cx = ax + (bx - ax) / 3; cy = ay + (by - ay) / 3;dx = bx - (bx - ax) / 3; dy = by - (by - ay) / 3;// float x = dx - cx, y = dy - cy;// ex = x * cos(pi / 3) - y * sin(pi / 3) + cx;// ey = x * sin(pi / 3) + y * cos(pi / 3) + cy;float a = atan((dy - cy)/(dx - cx));if(dx - cx < 0)a += pi;ex = cx + cos(a + pi/3) * newLen;ey = cy + sin(a + pi/3) * newLen; getNextLine(ax, ay, cx, cy);getNextLine(cx, cy, ex, ey);getNextLine(ex, ey, dx, dy);getNextLine(dx, dy, bx, by);return;
}int main(){window.clear();getNextLine(300, 600, 1600, 600);window.display();sf::Event event;while (window.isOpen()){while (window.pollEvent(event)){if (event.type == sf::Event::Closed) window.close();}}return 0;
}
当然计算ex, ey可以通过向量来搞
float x = dx - cx, y = dy - cy;
ex = x * cos(pi / 3) - y * sin(pi / 3) + cx;
ey = x * sin(pi / 3) + y * cos(pi / 3) + cy;
H树
关于H树的简介看这里
#include <iostream>
#include <cmath>
#include <SFML/Graphics.hpp>
const double pi = 3.1415926;
using namespace std;sf::RenderWindow window(sf::VideoMode(1920,1080), "Tree");const float s2 = sqrt(2);
int num = 100;
void getNextLine(float x, float y, float len, bool v){if(len < 5.0f)return;// if(num-- < 0)return;float ax, ay, bx, by, newLen;newLen = len / s2;if(v){ax = x; ay = y - newLen;bx = x; by = y + newLen;}else{ax = x - newLen; ay = y;bx = x + newLen; by = y;}getNextLine(ax, ay, newLen, !v);getNextLine(bx, by, newLen, !v);sf::Vertex line1[] = {sf::Vertex(sf::Vector2f(ax, ay), sf::Color::Cyan),sf::Vertex(sf::Vector2f(bx, by), sf::Color::Cyan)};window.draw(line1, 2, sf::Lines);return;
}int main(){window.clear();getNextLine(1000, 600, 300, 0);window.display();sf::Event event;while (window.isOpen()){while (window.pollEvent(event)){if (event.type == sf::Event::Closed) window.close();}}return 0;
}
当然你愿意搞得花里胡哨的话也不是不行
#include <iostream>
#include <cmath>
#include <SFML/Graphics.hpp>
#include<windows.h>
const double pi = 3.1415926;
using namespace std;sf::RenderWindow window(sf::VideoMode(1920,1080), "Tree");const float s2 = sqrt(2);
float minLen = 500.0f;
const int maxn = 1e5 + 5;
struct lines{sf::Vertex line[2];
}lines[maxn];
int num = 0;
sf::Color colors[] = {sf::Color::Cyan, sf::Color::Red, sf::Color::Green, sf::Color::Yellow, sf::Color::White};
int c = 0;
void getNextLine(float x, float y, float len, bool v){if(len < minLen)return;// if(num-- < 0)return;float ax, ay, bx, by, newLen;newLen = len / s2;if(v){ax = x; ay = y - newLen;bx = x; by = y + newLen;}else{ax = x - newLen; ay = y;bx = x + newLen; by = y;}getNextLine(ax, ay, newLen, !v);++c; c %= 5;getNextLine(bx, by, newLen, !v);++c; c %= 5;// sf::Vertex line1[] = {// sf::Vertex(sf::Vector2f(ax, ay), sf::Color::Cyan),// sf::Vertex(sf::Vector2f(bx, by), sf::Color::Cyan)// };// lines[num].line[0] = sf::Vertex(sf::Vector2f(ax, ay), sf::Color::Cyan);// lines[num].line[1] = sf::Vertex(sf::Vector2f(bx, by), sf::Color::Cyan);lines[num].line[0] = sf::Vertex(sf::Vector2f(ax, ay), colors[c]);lines[num].line[1] = sf::Vertex(sf::Vector2f(bx, by), colors[c]);++num;// ++c; c %= 5;// window.draw(line1, 2, sf::Lines);return;
}
// int lnum = 0;
void dispaly(){// lnum = num;num = 0;getNextLine(1000, 600, 300, 0);minLen -= 5.0f;if(minLen < 5)minLen = 500;// if(num >= lnum * 2){// ++c; c %= 5;// }
}
int main(){// window.clear();// getNextLine(1000, 600, 300, 0);// window.display();dispaly();sf::Clock clock;float timer = 0, delay = 0.1, time;sf::Event event;while (window.isOpen()){time = clock.getElapsedTime().asSeconds();timer += time;clock.restart();while (window.pollEvent(event)){if (event.type == sf::Event::Closed) window.close();}if(timer > delay){dispaly();timer = 0;}window.clear();for(int i = 0; i < num; ++i){window.draw(lines[i].line, 2, sf::Lines, sf::RenderStates::Default);}window.display();}return 0;
}
Julia集合
下面这份代码没有很好的调参,,所以,生成的图片也不怎么好看,等有时间修改一下在说吧。。
#include <iostream>
#include <cmath>
#include <SFML/Graphics.hpp>
#include<windows.h>
#include<complex>
const double pi = 3.1415926;
using namespace std;sf::RenderWindow window(sf::VideoMode(1920,1080), "Tree");sf::Color colors[10];
int col = 0;
void init(){for(int i = 0; i < 10; ++i){// colors[i] = sf::Color((128 - rand() % 128) + rand() % 128, (128 + rand() % 128) - rand() % 64, (100 + rand() % 120) - rand() % 100);// colors[i] = sf::Color((255 - rand() % 10 * i), (255 - rand() % 15 * i), (128 + rand() % 10 * i) % 255);colors[i] = sf::Color(i * 13, i * rand() % 255, i * 17);}
}
int getColor(double z){for(int i = 9; i >= 0; --i){// cout << i << endl;if(z <= 1.0 / (1 << i))return i;}return 0;
}
complex<double> c(-0.77097, -0.08545);
const int iter_max = 20;
complex<double> iter(complex<double> z){// cout << z << endl;for(int i = 1; i <= iter_max; ++i){z = z * z + c;if(std::abs(z) * std::abs(z) > 2)return z;}return z;
}void drawText(string s){// Declare and load a fontsf::Font font;cout << s << endl;font.loadFromFile("./res/consola.ttf");// Create a textsf::Text text(s, font);// text.setOrigin(sf::Vector2f(120, 100));text.setCharacterSize(30);text.setStyle(sf::Text::Bold);text.setFillColor(sf::Color::Red);// Draw itwindow.draw(text);
}// int lnum = 0;
int num;
void dispaly(){// window.clear(sf::Color::Black);window.clear(sf::Color::White);// window.clear();c = complex<double>(rand() % 10000 / 23333.0f, rand() % 10000 / 10007.f);drawText("c: " + to_string(c.real()) + " " + to_string(c.imag()));num = 0;double x, y;int max_x = 800, max_y = 600;double base_x = 500, base_y = 300;complex<double> z;sf::VertexArray points;points.resize(0);int step = 1;for(int i = 0; i < max_x; i += step){if(i % 100 == 0)cout << i << endl;for(int j = 0; j < max_y; j += step){// 坐标变换x = 2 *(i - double(max_x) / 2.0) / (double(max_x) / 2.0);y = 1.33 * (j - double(max_y) / 2.0) / (double(max_y) / 2.0);z = iter(complex<double>(x, y));// points.append(sf::Vertex(sf::Vector2f(x, y), sf::Color::Cyan));// sf::Vertex p(sf::Vector2f(i + base_x, j + base_y), colors[getColor(std::abs(z))]);// points.append(p);// continue;if(std::abs(z) * std::abs(z) <= 2){// if(z.imag() * z.imag() + z.real() * z.real() < 2){// sf::Vertex p(sf::Vector2f(i + base_x, j + base_y), sf::Color::Cyan);sf::Vertex p(sf::Vector2f(i + base_x, j + base_y), colors[getColor(std::abs(z))]);points.append(p);// if(points.getVertexCount() > 100){// points.setPrimitiveType(sf::Points);// window.draw(points);// points.resize(0);// window.display();// }// cout << i << " " << j << endl;}}}points.setPrimitiveType(sf::Points);cout << points.getVertexCount() << endl;window.draw(points);points.resize(0);window.display();
}
int main(){init();dispaly();sf::Clock clock;float timer = 0, delay = 5, time;sf::Event event;while (window.isOpen()){time = clock.getElapsedTime().asSeconds();timer += time;clock.restart();// dispaly();while (window.pollEvent(event)){if (event.type == sf::Event::Closed) window.close();}if(timer > delay){dispaly();timer = 0;}}return 0;
}
(未完ing)