README.md

Polyline2D

Polyline2D is a header-only C++17 library that generates a triangle mesh from a list of points. It can be used to draw thick lines with rendering APIs like OpenGL, which do not support line drawing out of the box.
It supports common joint and end cap styles.

Example usage

#include <Polyline2D/Polyline2D.h>
using namespace crushedpixel;

std::vector<Vec2> points{
		{ -0.25f, -0.5f  },  
		{ -0.25f,  0.5f  },  
		{  0.25f,  0.25f },  
		{  0.0f,   0.0f  },  
		{  0.25f, -0.25f },  
		{ -0.4f,  -0.25f }
};

auto thickness = 0.1f;
auto vertices = Polyline2D::create(points, thickness, 
		Polyline2D::JointStyle::ROUND,
		Polyline2D::EndCapStyle::SQUARE);

// render vertices, for example using OpenGL...

This code results in the following mesh: For demonstration purposes, the generated mesh is once rendered in wireframe mode (light green), and once in fill mode (transparent green).

The red points show the input points.

There is no overdraw within segments, only lines that overlap are filled twice.

For an example application using this software, visit Polyline2DExample.

Installation

Manual

To use Polyline2D, simply clone this repository and include the file Polyline2D.h from the include directory.

Using CMake

To install the header files into your global header directory, you can use CMake:

mkdir build
cd build
cmake ..
make install

You can then include the header file using #include <Polyline2D/Polyline2D.h>.

Attribution and similar projects

The concepts and maths behind this project are largely inspired by this amazing blog post by "To be an Artgrammer".

Check out the original author's project vaserenderer, which also offers a C# implementation based on fragment shaders.