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johannphilippe / hypercurve

Hypercurve is a library allowing you to combine several curve algorithms into a single 2D envelope. It is designed to be used in audio applications, for people who know how to enjoy a finely shaped curve. As shown above, you can perfectly combine gaussian curve with diocles cissoid curve, and plenty of other curve algorithms. The library can be used in C++, Lua, Csound and Faust.
GNU General Public License v3.0
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audio cpp17 csound curve envelope faust lua waveform

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HYPERCURVE

Hybrid hypercurve

What is it ?

Hypercurve is a library allowing you to combine several curve algorithms into a single 2D envelope. It is designed to be used in audio applications, for people who know how to enjoy a finely shaped curve. As shown above, you can perfectly combine gaussian curve with diocles cissoid curve, and plenty of other curve algorithms. The library can be used in C++, Lua, Csound and Faust.

Every curve algorithm is different. In audio applications, we use to assign envelopes to any kind of parameter. In computer music, the way a value goes up and down in time has a big influence on how we hear a sound. Thus, the possibility to create finely shaped envelopes is truly essential. This is the purpose of Hypercurve.

The above hypercurve is a combination of 1/8 diocles curve, 1/8 toxoid curve, 2/8 mouth curve, and 4/8 gauss curve.

Implemented curve algorithms

 How to install, and make it work

Go to Releases, and download the latest version.

Csound install

To install HYPERCURVES opcodes for Csound, the recommanded way is to move the csound_hypercurve library to the plugins repository of Csound.

Usually, the following instructions will work. If Csound is installed in another location, just change the following path :

 Lua use

On every OS Hypercurve is compiled for, you can write a lua script using Hypercurve in the Hypercurve directory and just use it from the terminal with ./luajit myscript.lua. Just change myscript.lua to the name of your script. On Windows, it should be ̀./luajit.exe myscript.lua.

How to use it

There are three ways to use it : in C++, Csound, Faust or in Lua. Cmake will help you build libraries that can be used in those languages. You will find C++ example under hypercurve_test/test.cpp, Csound example under csound_opcode/test.csd, and Lua example under lua_module/test.lua.

The basic syntax stands as follow :

A simple C++ example

#include"hypercurve.h"
using namespace hypercurve;
const int definition = 16384;
double y_start = 0;
curve c(definition, y_start, 
    {
        // segment(fractional_size, y_destination, curve
        segment(fraction(1,2), 1.0, share(cissoid_curve(1))),
        segment(0.5, 0.0, share(blackman_curve()))
    }); 
// Then access samples with double *get_samples() 
c.get_samples();

A simple Csound example

instr 1
    icrv = hc_hypercurve(2048, 0, 
                hc_segment(1/2, 1, hc_diocles_curve(1)),
                hc_segment(1/2, 0, hc_hanning_curve()))
    kenv = tablei:k(linseg:k(0, p3, 1), icrv, 1)
    ao = vco2(0.3, 300) * kenv
    outs(ao, ao)
endin

A simple Lua example

package.cpath = package.cpath .. ";/your/path/to/hypercurve/?.so;"
local hc = require("liblua_hypercurve")
local definition = 16384
local y_start = 0
local crv = hc.hypercurve(definition, y_start, 
    {
        hc.segment(1/2, 1.0, hc.cissoid_curve(1.0)),
        hc.sement(1/2, 0.0, hc.cubic_curve(0.0))
    })
// Write as 24 bits 48KHz wav
hc.write_as_wav("path/to/outfile.wav", crv)

A simple Faust example

hc = library("hypercurve.lib");
definition = 16384;
y_start = 0;
curve = hc.hypercurve(definition, y_start  (
    hc.segment(1/2, 1.0, hc.cissoid_curve(1.0)),
    hc.segment(1/2, 0.0, hc.cubic_curve)
));

// Run with interpolation
env = hc.runi(curve, os.phasor(1, 1));

Build

First clone the repo with submodules : git clone https://github.com/johannphilippe/hypercurve.git --recurse-submodules You should check that Lua is installed on your system. If it is not, or if compilation retrns error, you should install a Lua 5.1 version to the standard installation path. Make sure you have the dynamic library installed, and the headers lauxlib.h and lua.h are available on your system. Then : 

cd hypercurve
mkdir build && cd build
cmake .. -DBUILD_ALL=TRUE
make

If you just want to build for Faust, Lua or Csound, then just use 

cmake .. -DBUILD_CSOUND_OPCODE=TRUE
cmake .. -DBUILD_LUA_MODULE=TRUE
cmake .. -DBUILD_FAUST_LIB=TRUE

On some platforms (e.g. Windows) you might need to set the Lua paths with the following options :

cmake .. -DBUILD_LUA_MODULE=TRUE -DLUA_INCLUDE_DIR=/you/dir/include -DLUA_LIBRARIES=/path/to/lua.lib

Windows build for Lua is a bit more complicated, due to the way Windows searches for dynamic libraries. Wheter you provide LUA_LIBRARIES yourself or let CMake find it, you will need the .lib and .dll libraries of Lua to share the same name (except the extension) and the same path (as it is the case in standard Lua distributions). This will allow CMake to copy the Lua .dll dynamic library next to lua_hypercurve in the bin folder.

In order to build the Faust library, you will need Quom to be installed in your system. See the Faust README

The PNG writer fpng used for hypercurve has SSE support. This can be enabled with -DSSE=1.

The resulting binaries will all be located in bin directory. On Windows, lua_hypercurve.dll and hypercurve.dll require sndfile.dll to be in the same folder. lua_hypercurve.dll also requires the Lua .dll you linked against (e.g. lua5.1.dll). This must be considered when packaging the library to be embedded or used by another application.

 WASM/WASI port

After hours of tests, I'm struggling with this. I have not much knowledge about web, neither about Web Assembly. I probably need help.

TODO

Ideas :

Curves to implement

AI Hypercurves

NOTE : Start with markov models training first, not to burn your hands. Find an environment : C++ ? Ruby (lack audio libs..) ? Python (lack hypercurve support) ? Lua (lack everything else support) ?

Idea to implement a nn or another ML stuff to generate Hypercurves with a prior :

External libraries

The project uses LuaJIT as a submodule, allowing you to try HYPERCURVE out of the box.

It also includes source files from several open-source projects :

 LICENSE

The core of HYPERCURVE is licensed wit MIT. Easing curves - located in curve_lib.h - are derived from this work and thus are licensed as GNU General Public License 3.