# LCMGL.jl

**Repository Path**: Julialang/LCMGL.jl

## Basic Information

- **Project Name**: LCMGL.jl
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: MIT
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2018-03-12
- **Last Updated**: 2024-06-05

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# LCMGL

[![Build Status](https://travis-ci.org/rdeits/LCMGL.jl.svg?branch=master)](https://travis-ci.org/rdeits/LCMGL.jl)
[![codecov](https://codecov.io/gh/rdeits/LCMGL.jl/branch/master/graph/badge.svg)](https://codecov.io/gh/rdeits/LCMGL.jl)

This package provides Julia bindings for the [libbot lcmgl package](https://github.com/RobotLocomotion/libbot/tree/master/bot2-lcmgl), which allows OpenGL commands to be executed from a remote process using the [LCM](https://lcm-proj.github.io/) message passing system. It uses Julia's native C support to call directly into the `libbot2-lcmgl-client` library, so it should perform well with minimal overhead.

To use LCMGL, you'll need a viewer capable of listening to and displaying the resulting drawing commands. One excellent LCMGL-capable viewer is the `drake-visualizer` app, which is part of the free [Drake](drake.mit.edu) robotics toolbox.

# Usage

Construct a named LCMGL Client with:

```julia
lcmgl = LCMGLClient("client_name")
```

LCMGL functions are mapped to Julia functions:

```julia
color(lcmgl, rand(4)...)
sphere(lcmgl, rand(3), 0.1, 20, 20)
switch_buffer(lcmgl)
```

Multiple `LCMGL` clients can also share the same `LCM` object:

```julia
lcm = LCM()
gl1 = LCMGLClient(lcm, "gl1")
gl2 = LCMGLClient(lcm, "gl2")
```

A `do`-block syntax is also provided to make it easy to automatically construct and destroy an lcmgl client:

```julia
LCMGLClient("test") do lcmgl
    color(lcmgl, rand(4)...)
    sphere(lcmgl, rand(3), 0.1, 20, 20)
end
```

The `do`-block syntax will also automatically call `switch_buffer()` at the end of the block if there are any drawing commands waiting to be displayed.

## Memory Management

When an `LCM` or `LCMGLClient` object is finalized by the Julia garbage collector, the appropriate C function will also be called to destroy the underlying C object. If you want to explicitly free that C object early, you can call `close(lcm)` or `close(lcmgl)` yourself. You may find this useful if you get errors about too many file objects being used by LCM. Calling `close()` multiple times on the same Julia object is safe.

## Function Names

This package attempts to provide a consistent naming scheme for exported lcmgl functions: the `bot2_lcmgl_` prefix is always removed, and suffixes that exist only to indicate the number or type of arguments have also been removed. So, for example, `bot_lcmgl_vertex2d` has become `vertex(lcmgl, x, y)` and `bot_lcmgl_vertex3d` has become `vertex(lcmgl, x, y, z)`. There are a few exceptions: `begin` and `end` are reserved keywords in Julia, so they have become `begin_mode(lcmgl, mode)` and `end_mode(lcmgl)`, and `scale` is already defined in `Base`, so it has become `scale_axes(lcmgl, x_scale, y_scale, z_scale)`.