---
title: "openmpt S3 Class Objects"
output: rmarkdown::html_vignette
vignette: >
  %\VignetteIndexEntry{openmpt S3 Class Objects}
  %\VignetteEngine{knitr::rmarkdown}
  %\VignetteEncoding{UTF-8}
---

```{r, include = FALSE}
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)
```

This package has specified only one S3 class named `"openmpt"`. It is an external pointer
(type of `externalptr`) that points to the location where the OpenMPT module object is
stored in memory. It is stored in a format that can be handled by the libopenmpt library and
can be used to play or render the module and control options for playing and rendering.

## Initiating an `openmpt` class object

The only way to initiate an `openmpt` class object is by reading a supported module from a
file with `read_mod()`. There is no point in creating new `openmpt` objects from scratch anyway since
the package offers no features to modify the module (see also `vignette("openmpt-alternatives")`).

```{r initiate}
library(openmpt)
mod <- read_mod(system.file("cyberrid", "cyberrid.mod", package = "openmpt"))
```

## Using `openmpt` objects

Each `openmpt` object holds its own set of control and render parameters, which can be obtained
and modified with `control()` and `render_param()`. You can also control the volume of specific
or all channels (see `?"volume-control"`). Pitch and tempo can also be tweaked (see `?"pitch-tempo"`).
Use `play()` to play an `openmpt` object, and `convert_mod()` to convert it to a specific audio
file format.

There are many other functions that use `openmpt` objects as input. For a complete overview
check the [Reference page](https://pepijn-devries.github.io/openmpt/reference/index.html).
