R/mvdf_simple_material.R

In mikemahoney218/mvdf: A Minimum Viable Data Format for 3D Rendering via Blender

#' Class to attach basic material data to `mvdf_obj` objects
#'
#' @template mvdfdoc
#' @slot diffuse_color Diffuse color of the material, as an RGBA array of floats
#' scaled from 0-1.
#' @slot metallic Amount of mirror reflection for raytrace, as a float from
#' 0-1.
#' @slot roughness Roughness of the material, as a float from 0-1.
#' @family classes and related functions
#'
#' @exportClass mvdf_simple_material
methods::setClass("mvdf_simple_material",
  contains = "mvdf_obj",
  slots = c(
    diffuse_color = "character",
    metallic = "numeric",
    roughness = "numeric"
  )
)

setValidity("mvdf_simple_material", function(object) {
  error <- vector("character")
  n_issue <- 1

  if (length(object@idx) != length(object@diffuse_color) ||
    length(object@idx) != length(object@metallic) ||
    length(object@idx) != length(object@roughness)) {
    error[n_issue] <- "All slots must be the same length."
    n_issue <- n_issue + 1
  }
  
  miss_slots <- vapply(
    list(object@diffuse_color, object@metallic, object@roughness),
    any_missing,
    numeric(1)
    )
  names(miss_slots) <- c("diffuse_color", "metallic", "roughness")
  miss_slots <- miss_slots[miss_slots]
  if (!is.null(miss_slots)) {
    error[n_issue] <- paste("Slots cannot have missing values: ",
                            names(miss_slots))
    n_issue <- n_issue + 1
  }

  if (n_issue > 1) {
    return(paste0(error, collapse = "\n"))
  }
  return(TRUE)
})

#' Create a `mvdf_simple_material` object
#'
#' @param data Optionally, a data frame containing all the data necessary to
#' create a `mvdf_simple_material`. If `NULL`, all other arguments are
#' interpreted as data to use in constructing the object; if not `NULL`,
#' arguments are interpreted as the names of columns in `data` containing the
#' values for each slot.
#' @param diffuse_color Diffuse color of the material, in either a RGBA array
#' (if `translate_colors` is `TRUE`) or in any of the formats
#' understood by [grDevices::col2rgb] (if `translate_colors` is `FALSE`).
#' If colors are missing, they are set to gray80. If `translate_colors` is 
#' `NULL`, the default, this function attempts to infer if values are already
#' RGBA arrays.
#' @param metallic Amount of mirror reflection for raytrace, as a float from
#' 0-1. If missing, set to 0.
#' @param roughness Roughness of the material, as a float from 0-1. If missing,
#' set to 0.
#' @param translate_colors Logical: use `grDevices` to create RGBA arrays from
#' `diffuse_color`?
#' @param ... Additional arguments passed to [mvdf_obj]
#'
#' @export
mvdf_simple_material <- function(data = NULL,
                                 diffuse_color = "diffuse_color",
                                 metallic = "metallic",
                                 roughness = "roughness",
                                 translate_colors = NULL,
                                 ...) {
  res <- mvdf_obj(data = data, ...)
  res_mvdf <- mvdf(res)

  if (!is.null(data)) {
    diffuse_color <- eval_arg(data, diffuse_color)
    metallic <- eval_arg(data, metallic)
    roughness <- eval_arg(data, roughness)
  }

  length_out <- length(res_mvdf$idx)
  
  if (is.null(translate_colors)) {
    translate_colors <- all_missing(diffuse_color[[1]]) || 
      !grepl("\\d,", diffuse_color[[1]])
  }

  diffuse_color <- calc_val(
    diffuse_color,
    length_out,
    ifelse(translate_colors,
      "#CCCCCCCC",
      "0.8,0.8,0.8,0.8"
    )
  )
  metallic <- calc_val(metallic, length_out)
  roughness <- calc_val(roughness, length_out)

  if (translate_colors) {
    diffuse_color <- vapply(diffuse_color,
      function(x) {
        paste0(
          as.vector(grDevices::col2rgb(x, TRUE) / 255),
          collapse = ","
        )
      },
      character(1),
      USE.NAMES = FALSE
    )
  }

  methods::new("mvdf_simple_material",
    x = as.double(res_mvdf$x),
    y = as.double(res_mvdf$y),
    z = as.double(res_mvdf$z),
    idx = as.character(res_mvdf$idx),
    metadata = as.data.frame(metadata(res)),
    appendix = as.list(appendix(res)),
    diffuse_color = as.character(diffuse_color),
    metallic = as.numeric(metallic),
    roughness = as.numeric(roughness)
  )
}

setValidity("mvdf_simple_material", function(object) {
  error <- vector("character")
  n_issue <- 1

  if (any_missing(object@diffuse_color)) {
    error[n_issue] <- "@diffuse_color must not have any NULL or NA values."
    n_issue <- n_issue + 1
  }
  if (any_missing(object@metallic)) {
    error[n_issue] <- "@metallic must not have any NULL or NA values."
    n_issue <- n_issue + 1
  } else if (any(object@metallic < 0 | object@metallic > 1)) {
    error[n_issue] <- "@metallic must be between 0 and 1"
    n_issue <- n_issue + 1
  }
  if (any_missing(object@roughness)) {
    error[n_issue] <- "@roughness must not have any NULL or NA values."
    n_issue <- n_issue + 1
  } else if (any(object@roughness < 0 | object@roughness > 1)) {
    error[n_issue] <- "@roughness must be between 0 and 1"
    n_issue <- n_issue + 1
  }

  if (n_issue > 1) {
    return(paste0(error, collapse = "\n"))
  }
  return(TRUE)
})