---
title: "animate_imu"
output: rmarkdown::html_vignette
description:
  Learn how to use `animate_imu()` function to generate a 3-D animation of a 
  time series of orientations of an inertial measurement unit.
vignette: >
  %\VignetteIndexEntry{animate_imu}
  %\VignetteEngine{knitr::rmarkdown}
  %\VignetteEncoding{UTF-8}
---

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

This vignette describes how one may generate a 3-D animation of a time series of orientations of an inertial measurement unit (IMU).

We first follow the steps described in `vignette("imuf")` to generate a time series of orientations using the `walking_shin_1` dataset:

```{r setup, message = FALSE}
library(imuf)
library(purrr)
#
lst_ned_in <- as.list(as.data.frame(t(walking_shin_1))) %>% unname
dt <- 1/50
#
myCompUpdate <- function(initQ, accgyr) {
  acc <- accgyr[1:3]
  gyr <- accgyr[4:6]
  gain <- 0.1
  orientation <- compUpdate(acc, gyr, dt, initQ, gain)
  orientation
}
#
orientations <- purrr::accumulate(lst_ned_in, myCompUpdate, .init = c(1, 0, 0, 0))
#
head(orientations)
```

## 3-D animation of IMU orientations

Next we use the `animate_imu()` function to visualize a 3-D animation of the orienations.

```{r}
#
# time increment for animation needs to be in milli-seconds
animate_imu(orientations, dt*1000)
```


## 3-D animation of IMU orientations within Shiny

We will now illustrate how one may display the 3-D animation in Shiny.

```{r}
library(shiny)

ui = pageWithSidebar(
  headerPanel("render an IMU animation example"),
  sidebarPanel(actionButton("do", "See animation")),
  mainPanel(animate_imuOutput('orientations'))
)

server = function(input, output, session) {
  observeEvent(input$do, {
    output$orientations <- renderAnimate_imu(
      animate_imu(orientations, dt*1000)
    )
  })
}

shinyApp(ui = ui, server = server)
```