materials.R

#' Diffuse Material
#'
#' @param color Default `white`. The color of the surface. Can be either
#' a hexadecimal code, R color string, or a numeric rgb vector listing three intensities between `0` and `1`.
#' @param checkercolor Default `NA`. If not `NA`, determines the secondary color of the checkered surface.
#' Can be either a hexadecimal code, or a numeric rgb vector listing three intensities between `0` and `1`.
#' @param checkerperiod Default `3`. The period of the checker pattern. Increasing this value makes the checker
#' pattern bigger, and decreasing it makes it smaller
#' @param noise Default `0`. If not `0`, covers the surface in a turbulent marble pattern. This value will determine
#' the amount of turbulence in the texture.
#' @param noisephase Default `0`. The phase of the noise. The noise will repeat at `360`.
#' @param noiseintensity Default `10`. Intensity of the noise.
#' @param noisecolor Default `#000000`. The secondary color of the noise pattern.
#' Can be either a hexadecimal code, or a numeric rgb vector listing three intensities between `0` and `1`.
#' @param gradient_color Default `NA`. If not `NA`, creates a secondary color for a linear gradient
#' between the this color and color specified in `color`. Direction is determined by `gradient_transpose`.
#' @param gradient_transpose Default `FALSE`. If `TRUE`, this will use the `v` coordinate texture instead
#' of the `u` coordinate texture to map the gradient.
#' @param gradient_point_start Default `NA`. If not `NA`, this changes the behavior from mapping texture coordinates to
#' mapping to world space coordinates. This should be a length-3 vector specifying the x,y, and z points where the gradient
#' begins with value `color`.
#' @param gradient_point_end Default `NA`. If not `NA`, this changes the behavior from mapping texture coordinates to
#' mapping to world space coordinates. This should be a length-3 vector specifying the x,y, and z points where the gradient
#' begins with value `gradient_color`.
#' @param gradient_type Default `hsv`. Colorspace to calculate the gradient. Alternative `rgb`.
#' @param image_texture Default `""`. A 3-layer RGB array or filename to be used as the texture on the surface of the object.
#' @param image_repeat Default `1`. Number of times to repeat the image across the surface.
#' `u` and `v` repeat amount can be set independently if user passes in a length-2 vector.
#' @param alpha_texture Default `""`. A matrix or filename (specifying a greyscale image) to
#' be used to specify the transparency.
#' @param bump_texture Default `""`. A matrix, array, or filename (specifying a greyscale image) to
#' be used to specify a bump map for the surface.
#' @param bump_intensity Default `1`. Intensity of the bump map. High values may lead to unphysical results.
#' @param fog Default `FALSE`. If `TRUE`, the object will be a volumetric scatterer.
#' @param fogdensity Default `0.01`. The density of the fog. Higher values will produce more opaque objects.
#' @param sigma Default `NULL`. A number between 0 and Infinity specifying the roughness of the surface using the Oren-Nayar microfacet model.
#' Higher numbers indicate a roughed surface, where sigma is the standard deviation of the microfacet orientation angle. When 0, this reverts
#' to the default lambertian behavior.
#' @param importance_sample Default `FALSE`. If `TRUE`, the object will be sampled explicitly during
#' the rendering process. If the object is particularly important in contributing to the light paths
#' in the image (e.g. light sources, refracting glass ball with caustics, metal objects concentrating light),
#' this will help with the convergence of the image.
#'
#' @return Single row of a tibble describing the diffuse material.
#' @export
#' @importFrom  grDevices col2rgb
#'
#'@examplesIf interactive() || identical(Sys.getenv("IN_PKGDOWN"), "true")
#' #Generate the cornell box and add a single white sphere to the center
#' scene = generate_cornell() |>
#'   add_object(sphere(x=555/2,y=555/2,z=555/2,radius=555/8,material=diffuse()))
#' render_scene(scene, lookfrom=c(278,278,-800),lookat = c(278,278,0), samples=16,
#'              aperture=0, fov=40, ambient_light=FALSE, parallel=TRUE)
#'
#' #Add a checkered rectangular cube below
#' scene = scene |>
#'   add_object(cube(x=555/2,y=555/8,z=555/2,xwidth=555/2,ywidth=555/4,zwidth=555/2,
#'   material = diffuse(checkercolor="purple",checkerperiod=20)))
#' render_scene(scene, lookfrom=c(278,278,-800),lookat = c(278,278,0), samples=16,
#'              aperture=0, fov=40, ambient_light=FALSE, parallel=TRUE)
#'
#' #Add a marbled sphere
#' scene = scene |>
#'   add_object(sphere(x=555/2+555/4,y=555/2,z=555/2,radius=555/8,
#'   material = diffuse(noise=1/20)))
#' render_scene(scene, lookfrom=c(278,278,-800),lookat = c(278,278,0), samples=16,
#'              aperture=0, fov=40, ambient_light=FALSE, parallel=TRUE)
#'
#' #Add an rougher (Oren-Nayar) surface
#' scene = scene |>
#'   add_object(sphere(x=555/2-555/4,y=555/2,z=555/2,radius = 555/8,
#'   material = diffuse(sigma = 80)))
#' render_scene(scene, lookfrom=c(278,278,-800),lookat = c(278,278,0), samples=16,
#'              aperture=0, fov=40, ambient_light=FALSE, parallel=TRUE)
#'
#' #' #Add an line segment with a color gradient
#' scene = scene |>
#'   add_object(segment(start = c(555,450,450),end=c(0,450,450),radius = 50,
#'                      material = diffuse(color="#1f7326", gradient_color = "#a60d0d")))
#' render_scene(scene, lookfrom=c(278,278,-800),lookat = c(278,278,0), samples=16,
#'              aperture=0, fov=40, ambient_light=FALSE, parallel=TRUE)
diffuse = function(
  color = "#ffffff",
  checkercolor = NA,
  checkerperiod = 3,
  noise = 0,
  noisephase = 0,
  noiseintensity = 10,
  noisecolor = "#000000",
  gradient_color = NA,
  gradient_transpose = FALSE,
  gradient_point_start = NA,
  gradient_point_end = NA,
  gradient_type = "hsv",
  image_texture = "",
  image_repeat = 1,
  alpha_texture = "",
  bump_texture = "",
  bump_intensity = 1,
  fog = FALSE,
  fogdensity = 0.01,
  sigma = NULL,
  importance_sample = FALSE
) {
  if (all(!is.na(checkercolor))) {
    checkercolor = convert_color(checkercolor)
  } else {
    checkercolor = NA
  }
  if (all(!is.na(gradient_color))) {
    gradient_color = convert_color(gradient_color)
  } else {
    gradient_color = NA
  }
  if (
    !any(is.na(gradient_point_start)) &&
      !any(is.na(gradient_point_end)) &&
      !any(is.na(gradient_color))
  ) {
    stopifnot(length(gradient_point_start) == 3)
    stopifnot(length(gradient_point_end) == 3)
    stopifnot(is.numeric(gradient_point_start))
    stopifnot(is.numeric(gradient_point_end))
    gradient_point_info = c(gradient_point_start, gradient_point_end)
    is_world_gradient = TRUE
  } else {
    is_world_gradient = FALSE
    gradient_point_info = NA
  }

  info = convert_color(color)
  noisecolor = convert_color(noisecolor)
  image_texture = check_image_texture(image_texture)
  alpha_texture = check_image_texture(alpha_texture)
  bump_texture = check_image_texture(bump_texture)

  type = "diffuse"
  if (!is.null(sigma) && is.numeric(sigma)) {
    if (sigma < 0) {
      warning(
        "sigma must be greater than 0 (input: ",
        sigma,
        ")--ignoring and using lambertian model"
      )
    } else {
      if (sigma == 0) {
        type = "diffuse"
      } else {
        type = "oren-nayar"
        sigma = sigma * pi / 180
      }
    }
  } else {
    sigma = 0
  }
  if (length(image_repeat) == 1) {
    image_repeat = c(image_repeat, image_repeat)
  }
  stopifnot(checkerperiod != 0)
  ray_material(list(
    type = get_material_enum(type),
    properties = list(info),
    checkercolor = list(c(checkercolor, checkerperiod)),
    gradient_color = list(gradient_color),
    gradient_transpose = gradient_transpose,
    world_gradient = is_world_gradient,
    gradient_point_info = list(gradient_point_info),
    gradient_type = gradient_type,
    noise = noise,
    noisephase = noisephase * pi / 180,
    noiseintensity = noiseintensity,
    noisecolor = list(noisecolor),
    image = image_texture,
    image_repeat = list(image_repeat),
    alphaimage = alpha_texture,
    lightintensity = NA_real_,
    fog = fog,
    fogdensity = fogdensity,
    implicit_sample = importance_sample,
    sigma = sigma,
    glossyinfo = list(NA),
    bump_texture = bump_texture,
    bump_intensity = bump_intensity,
    roughness_texture = ""
  ))
}

#' Metallic Material
#'
#' @param color Default `white`. The color of the sphere. Can be either
#' a hexadecimal code, R color string, or a numeric rgb vector listing three intensities between `0` and `1`.
#' @param eta Default `0`. Wavelength dependent refractivity of the material (red, green, and blue channels).
#' If single number, will be repeated across all three channels.
#' @param kappa Default `0`. Wavelength dependent absorption of the material (red, green, and blue channels).
#' If single number, will be repeated across all three channels.
#' @param fuzz  Default `0`. Deprecated--Use the microfacet material instead, as it is designed for rough metals.
#' The roughness of the metallic surface. Maximum `1`.
#' @param checkercolor Default `NA`. If not `NA`, determines the secondary color of the checkered surface.
#' Can be either a hexadecimal code, or a numeric rgb vector listing three intensities between `0` and `1`.
#' @param checkerperiod Default `3`. The period of the checker pattern. Increasing this value makes the checker
#' pattern bigger, and decreasing it makes it smaller
#' @param noise Default `0`. If not `0`, covers the surface in a turbulent marble pattern. This value will determine
#' the amount of turbulence in the texture.
#' @param noisephase Default `0`. The phase of the noise. The noise will repeat at `360`.
#' @param noiseintensity Default `10`. Intensity of the noise.
#' @param noisecolor Default `#000000`. The secondary color of the noise pattern.
#' Can be either a hexadecimal code, or a numeric rgb vector listing three intensities between `0` and `1`.
#' @param gradient_color Default `NA`. If not `NA`, creates a secondary color for a linear gradient
#' between the this color and color specified in `color`. Direction is determined by `gradient_transpose`.
#' @param gradient_transpose Default `FALSE`. If `TRUE`, this will use the `v` coordinate texture instead
#' of the `u` coordinate texture to map the gradient.
#' @param gradient_point_start Default `NA`. If not `NA`, this changes the behavior from mapping texture coordinates to
#' mapping to world space coordinates. This should be a length-3 vector specifying the x,y, and z points where the gradient
#' begins with value `color`.
#' @param gradient_point_end Default `NA`. If not `NA`, this changes the behavior from mapping texture coordinates to
#' mapping to world space coordinates. This should be a length-3 vector specifying the x,y, and z points where the gradient
#' begins with value `gradient_color`.
#' @param gradient_type Default `hsv`. Colorspace to calculate the gradient. Alternative `rgb`.
#' @param image_texture Default `""`. A 3-layer RGB array or filename to be used as the texture on the surface of the object.
#' @param image_repeat Default `1`. Number of times to repeat the image across the surface.
#' `u` and `v` repeat amount can be set independently if user passes in a length-2 vector.
#' @param alpha_texture Default `""`. A matrix or filename (specifying a greyscale image) to be used to specify the transparency.
#' @param bump_texture Default `""`. A matrix, array, or filename (specifying a greyscale image) to
#' be used to specify a bump map for the surface.
#' @param bump_intensity Default `1`. Intensity of the bump map. High values may lead to unphysical results.
#' @param importance_sample Default `FALSE`. If `TRUE`, the object will be sampled explicitly during
#' the rendering process. If the object is particularly important in contributing to the light paths
#' in the image (e.g. light sources, refracting glass ball with caustics, metal objects concentrating light),
#' this will help with the convergence of the image.
#' @importFrom  grDevices col2rgb
#'
#' @return Single row of a tibble describing the metallic material.
#' @export
#'
#'@examplesIf interactive() || identical(Sys.getenv("IN_PKGDOWN"), "true")
#' # Generate the cornell box with a single chrome sphere in the center. For other metals,
#' # See the website refractiveindex.info for eta and k data, use wavelengths 5
#' # 80nm (R), 530nm (G), and 430nm (B).
#' scene = generate_cornell() |>
#'   add_object(sphere(x=555/2,y=555/2,z=555/2,radius=555/8,
#'   material=metal(eta=c(3.2176,3.1029,2.1839), k = c(3.3018,3.33,3.0339))))
#' render_scene(scene, lookfrom=c(278,278,-800),lookat = c(278,278,0), samples=16,
#'              aperture=0, fov=40, ambient_light=FALSE, parallel=TRUE)
#' #Add an aluminum rotated shiny metal block
#' scene = scene |>
#'   add_object(cube(x=380,y=150/2,z=200,xwidth=150,ywidth=150,zwidth=150,
#'   material = metal(eta = c(1.07,0.8946,0.523), k = c(6.7144,6.188,4.95)),angle=c(0,45,0)))
#' render_scene(scene, lookfrom=c(278,278,-800),lookat = c(278,278,0), samples=16,
#'              aperture=0, fov=40, ambient_light=FALSE, parallel=TRUE)
#' #Add a copper metal cube
#' scene = scene |>
#'   add_object(cube(x=150,y=150/2,z=300,xwidth=150,ywidth=150,zwidth=150,
#'                   material = metal(eta = c(0.497,0.8231,1.338),
#'                                    k = c(2.898,2.476,2.298)),
#'                   angle=c(0,-30,0)))
#' render_scene(scene, lookfrom=c(278,278,-800),lookat = c(278,278,0), samples=16,
#'              aperture=0, fov=40, ambient_light=FALSE, parallel=TRUE)
#'
#' #Finally, let's add a lead pipe
#' scene2 = scene |>
#'   add_object(cylinder(x=450,y=200,z=400,length=400,radius=30,
#'                   material = metal(eta = c(1.44,1.78,1.9),
#'                                    k = c(3.18,3.36,3.43)),
#'                   angle=c(0,-30,0)))
#' render_scene(scene2, lookfrom=c(278,278,-800),lookat = c(278,278,0), samples=16,
#'              aperture=0, fov=40, ambient_light=FALSE, parallel=TRUE)
metal = function(
  color = "#ffffff",
  eta = 0,
  kappa = 0,
  fuzz = 0,
  checkercolor = NA,
  checkerperiod = 3,
  noise = 0,
  noisephase = 0,
  noiseintensity = 10,
  noisecolor = "#000000",
  gradient_color = NA,
  gradient_transpose = FALSE,
  gradient_point_start = NA,
  gradient_point_end = NA,
  gradient_type = "hsv",
  image_texture = "",
  image_repeat = 1,
  alpha_texture = "",
  bump_texture = "",
  bump_intensity = 1,
  importance_sample = FALSE
) {
  color = convert_color(color)
  if (all(!is.na(checkercolor))) {
    checkercolor = convert_color(checkercolor)
  } else {
    checkercolor = NA
  }
  if (all(!is.na(gradient_color))) {
    gradient_color = convert_color(gradient_color)
  } else {
    gradient_color = NA
  }
  if (
    !any(is.na(gradient_point_start)) &&
      !any(is.na(gradient_point_end)) &&
      !any(is.na(gradient_color))
  ) {
    stopifnot(length(gradient_point_start) == 3)
    stopifnot(length(gradient_point_end) == 3)
    stopifnot(is.numeric(gradient_point_start))
    stopifnot(is.numeric(gradient_point_end))
    gradient_point_info = c(gradient_point_start, gradient_point_end)
    is_world_gradient = TRUE
  } else {
    is_world_gradient = FALSE
    gradient_point_info = NA
  }
  noisecolor = convert_color(noisecolor)
  image_texture = check_image_texture(image_texture)
  alpha_texture = check_image_texture(alpha_texture)
  bump_texture = check_image_texture(bump_texture)

  if (length(eta) == 1) {
    eta = c(eta, eta, eta)
  }
  if (length(kappa) == 1) {
    kappa = c(kappa, kappa, kappa)
  }
  if (length(eta) > 3 || length(eta) == 2) {
    stop("eta must be either single number or 3-component vector")
  }
  if (length(kappa) > 3 || length(kappa) == 2) {
    stop("kappa must be either single number or 3-component vector")
  }
  if (length(image_repeat) == 1) {
    image_repeat = c(image_repeat, image_repeat)
  }
  glossyinfo = list(c(1, 0, 0, eta, kappa))
  ray_material(list(
    type = get_material_enum("metal"),
    properties = list(c(color, fuzz)),
    checkercolor = list(c(checkercolor, checkerperiod)),
    gradient_color = list(gradient_color),
    gradient_transpose = gradient_transpose,
    world_gradient = is_world_gradient,
    gradient_point_info = list(gradient_point_info),
    gradient_type = gradient_type,
    noise = noise,
    noisephase = noisephase * pi / 180,
    noiseintensity = noiseintensity,
    noisecolor = list(noisecolor),
    lightinfo = list(NA),
    image = image_texture,
    image_repeat = list(image_repeat),
    alphaimage = alpha_texture,
    lightintensity = NA_real_,
    fog = FALSE,
    fogdensity = 0.01,
    implicit_sample = importance_sample,
    sigma = 0,
    glossyinfo = glossyinfo,
    bump_texture = bump_texture,
    bump_intensity = bump_intensity,
    roughness_texture = ""
  ))
}

#' Dielectric (glass) Material
#'
#'
#' @param color Default `white`. The color of the surface. Can be either
#' a hexadecimal code, R color string, or a numeric rgb vector listing three intensities between `0` and `1`.
#' @param refraction Default `1.5`. The index of refraction.
#' @param attenuation Default `c(0,0,0)`. The Beer-Lambert color-channel specific exponential attenuation
#' through the material. Higher numbers will result in less of that color making it through the material. If a character string
#' is provided (either as a named R color or a hex string), this will be converted to a length-3 vector equal to one minus the RGB
#' color vector, which should approximate the color being passed.
#' Note: This assumes the object has a closed surface.
#' @param attenuation_intensity Default `1`. Changes the attenuation by a multiplicative factor. Values lower than one will make the
#' dielectric more transparent, while values greater than one will make the glass more opaque.
#' @param priority Default `0`. When two dielectric materials overlap, the one with the lower priority value
#' is used for intersection. NOTE: If the camera is placed inside a dielectric object, its priority value
#' will not be taken into account when determining hits to other objects also inside the object.
#' @param importance_sample Default `FALSE`. If `TRUE`, the object will be sampled explicitly during
#' the rendering process. If the object is particularly important in contributing to the light paths
#' in the image (e.g. light sources, refracting glass ball with caustics, metal objects concentrating light),
#' this will help with the convergence of the image.
#' @param bump_texture Default `""`. A matrix, array, or filename (specifying a greyscale image) to
#' be used to specify a bump map for the surface.
#' @param bump_intensity Default `1`. Intensity of the bump map. High values may lead to unphysical results.
#'
#' @return Single row of a tibble describing the dielectric material.
#' @export
#'
#'@examplesIf interactive() || identical(Sys.getenv("IN_PKGDOWN"), "true")
#' #Generate a checkered ground
#' scene = generate_ground(depth=-0.5, material = diffuse(checkercolor="grey30",checkerperiod=2))
#' #Add a glass sphere
#' scene |>
#'   add_object(sphere(x=-0.5,radius=0.5,material=dielectric())) |>
#'   render_scene(parallel=TRUE,samples=16)
#'
#' #Add a rotated colored glass cube
#' scene |>
#'   add_object(sphere(x=-0.5,radius=0.5,material=dielectric())) |>
#'   add_object(cube(x=0.5,xwidth=0.5,material=dielectric(color="darkgreen"),angle=c(0,-45,0))) |>
#'   render_scene(parallel=TRUE,samples=16)
#'
#' #Add an area light behind and at an angle and turn off the ambient lighting
#' scene |>
#'   add_object(sphere(x=-0.5,radius=0.5,material=dielectric())) |>
#'   add_object(cube(x=0.5,xwidth=0.5,material=dielectric(color="darkgreen"),angle=c(0,-45,0))) |>
#'   add_object(yz_rect(z=3,y=1,x=0,zwidth=3,ywidth=0.5,
#'                      material=light(intensity=30),
#'                      angle=c(0,90,-45), order_rotation = c(3,2,1))) |>
#'   render_scene(parallel=TRUE,aperture=0, ambient_light=FALSE,samples=16, lookfrom=c(0,3,-10))
#'
#' #Color glass using Beer-Lambert attenuation, which attenuates light on a per-channel
#' #basis as it travels through the material. This effect is what gives some types of glass
#' #a green glow at the edges. We will get this effect by setting a lower attenuation value
#' #for the `green` (second) channel in the dielectric `attenuation` argument.
#' generate_ground(depth=-0.5,material=diffuse(checkercolor="grey30",checkerperiod=2)) |>
#'   add_object(sphere(z=5,x=-0.5,y=1,material=light(intensity=10))) |>
#'   add_object(cube(y=0.3,ywidth=0.1,xwidth=2,zwidth=2,angle=c(45,110,0),
#'                   material=dielectric(attenuation=c(1.2,0.2,1.2),
#'                                       attenuation_intensity=2))) |>
#'   render_scene(parallel=TRUE, samples = 16)
#'
#' #If you have overlapping dielectrics, the `priority` value can help disambiguate what
#' #object wins. Here, I place a bubble inside a cube by setting a lower priority value and
#' #making the inner sphere have a index of refraction of 1. I also place spheres at the corners.
#' generate_ground(depth=-0.51,material=diffuse(checkercolor="grey30",checkerperiod=2)) |>
#'   add_object(cube(material = dielectric(priority=2, attenuation = c(10,3,10)))) |>
#'   add_object(sphere(radius=0.49,material = dielectric(priority=1, refraction=1))) |>
#'   add_object(sphere(radius=0.25,x=0.5,z=-0.5,y=0.5,
#'                     material = dielectric(priority=0,attenuation = c(10,3,10) ))) |>
#'   add_object(sphere(radius=0.25,x=-0.5,z=0.5,y=0.5,
#'                     material = dielectric(priority=0,attenuation = c(10,3,10)))) |>
#'   add_object(sphere(y=5,x=-5,radius=3,material=light())) |>
#'   render_scene(parallel=TRUE, samples = 16,lookfrom=c(5,1,5))
dielectric = function(
  color = "white",
  refraction = 1.5,
  attenuation = c(0, 0, 0),
  attenuation_intensity = 1,
  priority = 0,
  importance_sample = FALSE,
  bump_texture = "",
  bump_intensity = 1
) {
  color = convert_color(color)
  stopifnot(
    attenuation_intensity >= 0 &&
      is.numeric(attenuation_intensity) &&
      !is.na(attenuation_intensity) &&
      !is.infinite(attenuation_intensity)
  )
  if (is.character(attenuation)) {
    attenuation = 1 - convert_color(attenuation)
  }
  attenuation = attenuation * attenuation_intensity

  bump_texture = check_image_texture(bump_texture)
  ray_material(list(
    type = get_material_enum("dielectric"),
    properties = list(c(color, refraction, attenuation, priority)),
    checkercolor = list(NA),
    gradient_color = list(NA),
    gradient_transpose = FALSE,
    world_gradient = FALSE,
    gradient_point_info = list(NA),
    gradient_type = NA,
    noise = 0,
    noisephase = 0,
    noiseintensity = 0,
    noisecolor = list(c(0, 0, 0)),
    image = "",
    image_repeat = list(c(1, 1)),
    alphaimage = "",
    lightintensity = NA_real_,
    fog = FALSE,
    fogdensity = NA_real_,
    implicit_sample = importance_sample,
    sigma = 0,
    glossyinfo = list(NA),
    bump_texture = bump_texture,
    bump_intensity = bump_intensity,
    roughness_texture = ""
  ))
}

#' Microfacet Material
#'
#' @param color Default `white`. The color of the surface. Can be either
#' a hexadecimal code, R color string, or a numeric rgb vector listing three intensities between `0` and `1`.
#' @param roughness Default `0.0001`. Roughness of the surface, between `0` (smooth) and `1` (diffuse).
#' Can be either a single number, or two numbers indicating an anisotropic distribution of normals. `0` is a smooth surface, while
#' `1` is extremely rough. This can be used to create a wide-variety of materials (e.g. `0-0.01` is specular
#' metal, `0.02`-`0.1` is brushed metal, `0.1`-`0.3` is a rough metallic surface , `0.3`-`0.5` is diffuse, and
#' above that is a rough satin-like material).
#' Two numbers will specify the x and y roughness separately (e.g. `roughness = c(0.01, 0.001)` gives an
#' etched metal effect). If `0`, this defaults to the `metal()` material for faster evaluation.
#' @param transmission Default `FALSE`. If `TRUE`, this material will be a rough dielectric instead of a rough metallic surface.
#' @param eta Default `0`. Wavelength dependent refractivity of the material (red, green, and blue channels).
#' If single number, will be repeated across all three channels. If `transmission = TRUE`, this is a single value representing the
#' index of refraction of the material.
#' @param kappa Default `0`. Wavelength dependent absorption of the material (red, green, and blue channels).
#' If single number, will be repeated across all three channels. If `transmission = TRUE`, this length-3 vector specifies
#' the attenuation of the dielectric (analogous to the dielectric `attenuation` argument).
#' @param microfacet Default `tbr`.  Type of microfacet distribution. Alternative option `beckmann`.
#' @param checkercolor Default `NA`. If not `NA`, determines the secondary color of the checkered surface.
#' Can be either a hexadecimal code, or a numeric rgb vector listing three intensities between `0` and `1`.
#' @param checkerperiod Default `3`. The period of the checker pattern. Increasing this value makes the checker
#' pattern bigger, and decreasing it makes it smaller
#' @param noise Default `0`. If not `0`, covers the surface in a turbulent marble pattern. This value will determine
#' the amount of turbulence in the texture.
#' @param noisephase Default `0`. The phase of the noise. The noise will repeat at `360`.
#' @param noiseintensity Default `10`. Intensity of the noise.
#' @param noisecolor Default `#000000`. The secondary color of the noise pattern.
#' Can be either a hexadecimal code, or a numeric rgb vector listing three intensities between `0` and `1`.
#' @param gradient_color Default `NA`. If not `NA`, creates a secondary color for a linear gradient
#' between the this color and color specified in `color`. Direction is determined by `gradient_transpose`.
#' @param gradient_transpose Default `FALSE`. If `TRUE`, this will use the `v` coordinate texture instead
#' of the `u` coordinate texture to map the gradient.
#' @param gradient_point_start Default `NA`. If not `NA`, this changes the behavior from mapping texture coordinates to
#' mapping to world space coordinates. This should be a length-3 vector specifying the x,y, and z points where the gradient
#' begins with value `color`.
#' @param gradient_point_end Default `NA`. If not `NA`, this changes the behavior from mapping texture coordinates to
#' mapping to world space coordinates. This should be a length-3 vector specifying the x,y, and z points where the gradient
#' begins with value `gradient_color`.
#' @param gradient_type Default `hsv`. Colorspace to calculate the gradient. Alternative `rgb`.
#' @param image_texture Default `""`. A 3-layer RGB array or filename to be used as the texture on the surface of the object.
#' @param image_repeat Default `1`. Number of times to repeat the image across the surface.
#' `u` and `v` repeat amount can be set independently if user passes in a length-2 vector.
#' @param alpha_texture Default `""`. A matrix or filename (specifying a greyscale image) to be used to specify the transparency.
#' @param bump_texture Default `""`. A matrix, array, or filename (specifying a greyscale image) to
#' be used to specify a bump map for the surface.
#' @param bump_intensity Default `1`. Intensity of the bump map. High values may lead to unphysical results.
#' @param roughness_texture Default `""`. A matrix, array, or filename (specifying a greyscale image) to
#' be used to specify a roughness map for the surface.
#' @param roughness_range Default ` c(0.0001, 0.2)`. This is a length-2 vector that specifies the range of roughness values
#' that the `roughness_texture` can take.
#' @param roughness_flip Default `FALSE`. Setting this to `TRUE` flips the roughness values specified in the `roughness_texture`
#' so high values are now low values and vice versa.
#' @param importance_sample Default `FALSE`. If `TRUE`, the object will be sampled explicitly during
#' the rendering process. If the object is particularly important in contributing to the light paths
#' in the image (e.g. light sources, refracting glass ball with caustics, metal objects concentrating light),
#' this will help with the convergence of the image.
#'
#' @return Single row of a tibble describing the microfacet material.
#' @export
#'
#'@examplesIf interactive() || identical(Sys.getenv("IN_PKGDOWN"), "true")
#' # Generate a golden egg, using eta and kappa taken from physical measurements
#' # See the website refractiveindex.info for eta and k data, use
#' # wavelengths 580nm (R), 530nm (G), and 430nm (B).
#' generate_cornell() |>
#'   add_object(ellipsoid(x=555/2,555/2,y=150, a=100,b=150,c=100,
#'              material=microfacet(roughness=0.1,
#'                                  eta=c(0.216,0.42833,1.3184), kappa=c(3.239,2.4599,1.8661)))) |>
#'  render_scene(lookfrom=c(278,278,-800),lookat = c(278,278,0), samples=16,
#'              aperture=0, fov=40, parallel=TRUE,clamp_value=10)
#' #Make the roughness anisotropic (either horizontal or vertical), adding an extra light in front
#' #to show off the different microfacet orientations
#' generate_cornell() |>
#'   add_object(sphere(x=555/2,z=50,y=75,radius=20,material=light())) |>
#'   add_object(ellipsoid(x=555-150,555/2,y=150, a=100,b=150,c=100,
#'              material=microfacet(roughness=c(0.3,0.1),
#'                                  eta=c(0.216,0.42833,1.3184), kappa=c(3.239,2.4599,1.8661)))) |>
#'  add_object(ellipsoid(x=150,555/2,y=150, a=100,b=150,c=100,
#'              material=microfacet(roughness=c(0.1,0.3),
#'                                  eta=c(0.216,0.42833,1.3184), kappa=c(3.239,2.4599,1.8661)))) |>
#'  render_scene(lookfrom=c(278,278,-800),lookat = c(278,278,0), samples=16,
#'              aperture=0, fov=40,  parallel=TRUE,clamp_value=10)
#' #Render a rough silver R with a smaller golden egg in front
#' generate_cornell() |>
#'   add_object(obj_model(r_obj(simple_r = TRUE),
#'                        x=555/2,z=350,y=0, scale_obj = 200, angle=c(0,20,0),
#'              material=microfacet(roughness=0.2,
#'                                  eta=c(1.1583,0.9302,0.5996), kappa=c(6.9650,6.396,5.332)))) |>
#'  add_object(ellipsoid(x=200,z=200,y=80, a=50,b=80,c=50,
#'              material=microfacet(roughness=0.1,
#'                                  eta=c(0.216,0.42833,1.3184), kappa=c(3.239,2.4599,1.8661)))) |>
#'  render_scene(lookfrom=c(278,278,-800),lookat = c(278,278,0), samples=16,
#'              aperture=0, fov=40, parallel=TRUE,clamp_value=10)
#' #Increase the roughness
#' generate_cornell() |>
#'   add_object(obj_model(r_obj(simple_r = TRUE),
#'                        x=555/2,z=350,y=0, scale_obj = 200, angle=c(0,20,0),
#'              material=microfacet(roughness=0.5,
#'                                  eta=c(1.1583,0.9302,0.5996), kappa=c(6.9650,6.396,5.332)))) |>
#'  add_object(ellipsoid(x=200,z=200,y=80, a=50,b=80,c=50,
#'              material=microfacet(roughness=0.3,
#'                                  eta=c(0.216,0.42833,1.3184), kappa=c(3.239,2.4599,1.8661)))) |>
#'  render_scene(lookfrom=c(278,278,-800),lookat = c(278,278,0), samples=16,
#'              aperture=0, fov=40, parallel=TRUE,clamp_value=10)
#'  #Use transmission for a rough dielectric
#' generate_cornell() |>
#'   add_object(text3d(label="XY Plane", z=550,y=555/2,x=555/2,text_height=200,
#'                     orientation = "xy",
#'                     material=diffuse(color="grey10"), angle=c(0,0,0))) |>
#'   add_object(obj_model(r_obj(simple_r = TRUE),
#'                        x=555/2,z=350,y=0, scale_obj = 200, angle=c(0,20,0),
#'              material=microfacet(roughness=0.25, transmission=T, eta=1.3))) |>
#'  add_object(ellipsoid(x=200,z=200,y=80, a=50,b=80,c=50,
#'              material=microfacet(roughness=0.15, transmission=T, eta=1.6))) |>
#'  render_scene(lookfrom=c(278,278,-800),lookat = c(278,278,0), samples=64,
#'              aperture=0, fov=40, parallel=TRUE,clamp_value=10, min_variance=1e-6)
microfacet = function(
  color = "white",
  roughness = 0.0001,
  transmission = FALSE,
  eta = 0,
  kappa = 0,
  microfacet = "tbr",
  checkercolor = NA,
  checkerperiod = 3,
  noise = 0,
  noisephase = 0,
  noiseintensity = 10,
  noisecolor = "#000000",
  gradient_color = NA,
  gradient_transpose = FALSE,
  gradient_point_start = NA_real_,
  gradient_point_end = NA_real_,
  gradient_type = "hsv",
  image_texture = "",
  image_repeat = 1,
  alpha_texture = "",
  bump_texture = "",
  bump_intensity = 1,
  roughness_texture = "",
  roughness_range = c(0.0001, 0.2),
  roughness_flip = FALSE,
  importance_sample = FALSE
) {
  microtype = switch(microfacet, "tbr" = 1, "beckmann" = 2, 1)
  roughness[roughness <= 0] = 0
  roughness[roughness > 1] = 1
  if (length(roughness) == 1) {
    alphax = roughness^2
    alphay = roughness^2
  } else {
    alphax = roughness[1]^2
    alphay = roughness[2]^2
  }
  if (length(roughness_range) != 2) {
    stop("length of roughness_range must be 2")
  }
  if (roughness_range[1] > roughness_range[2]) {
    roughness_range = rev(roughness_range)
  }
  if (
    roughness_range[1] == roughness_range[2] && nchar(roughness_texture) > 0
  ) {
    roughness_texture = ""
    roughness = roughness_range[1]
  }
  if (length(eta) == 1) {
    eta = c(eta, eta, eta)
  }
  if (length(kappa) == 1) {
    kappa = c(kappa, kappa, kappa)
  }
  if (length(eta) > 3 || length(eta) == 2) {
    stop("eta must be either single number or 3-component vector")
  }
  if (length(kappa) > 3 || length(kappa) == 2) {
    stop("kappa must be either single number or 3-component vector")
  }
  color = convert_color(color)
  if (all(!is.na(checkercolor))) {
    checkercolor = convert_color(checkercolor)
  } else {
    checkercolor = NA
  }
  if (all(!is.na(gradient_color))) {
    gradient_color = convert_color(gradient_color)
  } else {
    gradient_color = NA
  }
  if (
    !any(is.na(gradient_point_start)) &&
      !any(is.na(gradient_point_end)) &&
      !any(is.na(gradient_color))
  ) {
    stopifnot(length(gradient_point_start) == 3)
    stopifnot(length(gradient_point_end) == 3)
    stopifnot(is.numeric(gradient_point_start))
    stopifnot(is.numeric(gradient_point_end))
    gradient_point_info = c(gradient_point_start, gradient_point_end)
    is_world_gradient = TRUE
  } else {
    is_world_gradient = FALSE
    gradient_point_info = NA
  }
  noisecolor = convert_color(noisecolor)
  image_texture = check_image_texture(image_texture)
  alpha_texture = check_image_texture(alpha_texture)
  bump_texture = check_image_texture(bump_texture)
  roughness_texture = check_image_texture(roughness_texture)

  if (length(image_repeat) == 1) {
    image_repeat = c(image_repeat, image_repeat)
  }
  roughness_flip = ifelse(roughness_flip, 1, 0)
  glossyinfo = list(c(
    microtype,
    alphax,
    alphay,
    eta,
    kappa,
    roughness_range,
    roughness_flip
  ))
  if (alphax == 0 && alphay == 0) {
    if (!transmission) {
      ray_material(list(
        type = get_material_enum("metal"),
        properties = list(c(color, 0)),
        gradient_color = list(gradient_color),
        gradient_transpose = FALSE,
        world_gradient = is_world_gradient,
        gradient_point_info = list(gradient_point_info),
        gradient_type = gradient_type,
        checkercolor = list(c(checkercolor, checkerperiod)),
        noise = noise,
        noisephase = noisephase * pi / 180,
        noiseintensity = noiseintensity,
        noisecolor = list(noisecolor),
        image = image_texture,
        image_repeat = list(image_repeat),
        alphaimage = alpha_texture,
        lightintensity = NA_real_,
        fog = FALSE,
        fogdensity = NA_real_,
        implicit_sample = importance_sample,
        sigma = 0,
        glossyinfo = glossyinfo,
        bump_texture = bump_texture,
        bump_intensity = bump_intensity,
        roughness_texture = ""
      ))
    } else {
      ray_material(list(
        type = get_material_enum("dielectric"),
        properties = list(c(color, eta[1], c(0, 0, 0), 0)),
        gradient_color = list(gradient_color),
        gradient_transpose = FALSE,
        world_gradient = is_world_gradient,
        gradient_point_info = list(gradient_point_info),
        gradient_type = gradient_type,
        checkercolor = list(c(checkercolor, checkerperiod)),
        noise = noise,
        noisephase = noisephase * pi / 180,
        noiseintensity = noiseintensity,
        noisecolor = list(noisecolor),
        image = image_texture,
        image_repeat = list(image_repeat),
        alphaimage = alpha_texture,
        lightintensity = NA_real_,
        fog = FALSE,
        fogdensity = NA_real_,
        implicit_sample = importance_sample,
        sigma = 0,
        glossyinfo = glossyinfo,
        bump_texture = bump_texture,
        bump_intensity = bump_intensity,
        roughness_texture = ""
      ))
    }
  } else {
    if (transmission) {
      typeval = "mf-t"
    } else {
      typeval = "mf"
    }
    ray_material(list(
      type = get_material_enum(typeval),
      properties = list(c(color)),
      gradient_color = list(gradient_color),
      gradient_transpose = FALSE,
      world_gradient = is_world_gradient,
      gradient_point_info = list(gradient_point_info),
      gradient_type = gradient_type,
      checkercolor = list(c(checkercolor, checkerperiod)),
      noise = noise,
      noisephase = noisephase * pi / 180,
      noiseintensity = noiseintensity,
      noisecolor = list(noisecolor),
      image = image_texture,
      image_repeat = list(image_repeat),
      alphaimage = alpha_texture,
      lightintensity = NA_real_,
      fog = FALSE,
      fogdensity = NA_real_,
      implicit_sample = importance_sample,
      sigma = 0,
      glossyinfo = glossyinfo,
      bump_texture = bump_texture,
      bump_intensity = bump_intensity,
      roughness_texture = roughness_texture
    ))
  }
}

#' Light Material
#'
#' @param color Default `white`. The color of the light Can be either
#' a hexadecimal code, R color string, or a numeric rgb vector listing three intensities between `0` and `1`.
#' @param intensity Default `10`. If a positive value, this will turn this object into a light emitting the value specified
#' in `color` (ignoring other properties). Higher values will produce a brighter light.
#' @param importance_sample Default `TRUE`. Keeping this on for lights improves the convergence of the rendering
#' algorithm, in most cases. If the object is particularly important in contributing to the light paths
#' in the image (e.g. light sources, refracting glass ball with caustics, metal objects concentrating light),
#' this will help with the convergence of the image.
#' @param spotlight_focus Default `NA`, no spotlight. Otherwise, a length-3 numeric vector specifying
#' the x/y/z coordinates that the spotlight should be focused on. Only works for spheres and rectangles.
#' @param spotlight_width Default `30`. Angular width of the spotlight.
#' @param spotlight_start_falloff Default `15`. Angle at which the light starts fading in intensity.
#' @param invisible Default `FALSE`. If `TRUE`, the light itself will be invisible.
#' @param image_texture Default `""`. A 3-layer RGB array or filename to be used as the texture on the surface of the object.
#' @param image_repeat Default `1`. Number of times to repeat the image across the surface.
#' `u` and `v` repeat amount can be set independently if user passes in a length-2 vector.
#' @param gradient_color Default `NA`. If not `NA`, creates a secondary color for a linear gradient
#' between the this color and color specified in `color`. Direction is determined by `gradient_transpose`.
#' @param gradient_transpose Default `FALSE`. If `TRUE`, this will use the `v` coordinate texture instead
#' of the `u` coordinate texture to map the gradient.
#' @param gradient_point_start Default `NA`. If not `NA`, this changes the behavior from mapping texture coordinates to
#' mapping to world space coordinates. This should be a length-3 vector specifying the x,y, and z points where the gradient
#' begins with value `color`.
#' @param gradient_point_end Default `NA`. If not `NA`, this changes the behavior from mapping texture coordinates to
#' mapping to world space coordinates. This should be a length-3 vector specifying the x,y, and z points where the gradient
#' begins with value `gradient_color`.
#' @param gradient_type Default `hsv`. Colorspace to calculate the gradient. Alternative `rgb`.
#'
#' @return Single row of a tibble describing the light material.
#' @export
#' @importFrom  grDevices col2rgb
#'
#'@examplesIf interactive() || identical(Sys.getenv("IN_PKGDOWN"), "true")
#' #Generate the cornell box without a light and add a single white sphere to the center
#' scene = generate_cornell(light=FALSE) |>
#'   add_object(sphere(x=555/2,y=555/2,z=555/2,radius=555/8,material=light()))
#' render_scene(scene, lookfrom=c(278,278,-800),lookat = c(278,278,0), samples=16,
#'              aperture=0, fov=40, ambient_light=FALSE, parallel=TRUE)
#'
#' #Remove the light for direct camera rays, but keep the lighting
#' scene = generate_cornell(light=FALSE) |>
#'   add_object(sphere(x=555/2,y=555/2,z=555/2,radius=555/8,
#'              material=light(intensity=15,invisible=TRUE)))
#' render_scene(scene, lookfrom=c(278,278,-800),lookat = c(278,278,0), samples=16,
#'              aperture=0, fov=40, ambient_light=FALSE, parallel=TRUE)
#'
#' #All gather around the orb
#' scene = generate_ground(material = diffuse(checkercolor="grey50")) |>
#'   add_object(sphere(radius=0.25,material=light(intensity=90,color="#f11"))) |>
#'   add_object(obj_model(r_obj(), scale=2.5,z=-3,x=-1.25,y=0, angle=c(0,235,0))) |>
#'   add_object(pig(scale=0.3, x=1.5,z=-2,y=-1.5,angle=c(0,-135,0)))
#' render_scene(scene, samples=16, parallel=TRUE, clamp_value=10, lookfrom=c(0,0,10))
light = function(
  color = "#ffffff",
  intensity = 10,
  importance_sample = TRUE,
  spotlight_focus = NA,
  spotlight_width = 30,
  spotlight_start_falloff = 15,
  invisible = FALSE,
  image_texture = "",
  image_repeat = 1,
  gradient_color = NA,
  gradient_transpose = FALSE,
  gradient_point_start = NA,
  gradient_point_end = NA,
  gradient_type = "hsv"
) {
  info = convert_color(color)
  image_texture = check_image_texture(image_texture)
  if (length(image_repeat) == 1) {
    image_repeat = c(image_repeat, image_repeat)
  }
  if (all(!is.na(gradient_color))) {
    gradient_color = convert_color(gradient_color)
  } else {
    gradient_color = NA_real_
  }
  if (
    !any(is.na(gradient_point_start)) &&
      !any(is.na(gradient_point_end)) &&
      !any(is.na(gradient_color))
  ) {
    stopifnot(length(gradient_point_start) == 3)
    stopifnot(length(gradient_point_end) == 3)
    stopifnot(is.numeric(gradient_point_start))
    stopifnot(is.numeric(gradient_point_end))
    gradient_point_info = c(gradient_point_start, gradient_point_end)
    is_world_gradient = TRUE
  } else {
    is_world_gradient = FALSE
    gradient_point_info = NA_real_
  }
  if (invisible) {
    invisible = 1
  } else {
    invisible = 0
  }
  if (all(!is.na(spotlight_focus))) {
    stopifnot(length(spotlight_focus) == 3)
    spotlight_width = min(c(spotlight_width, 180))
    spotlight_start_falloff = min(c(spotlight_start_falloff, 90))
    info = c(
      info,
      spotlight_focus,
      cospi(spotlight_width / 180),
      cospi(spotlight_start_falloff / 180),
      invisible
    )
    ray_material(list(
      type = get_material_enum("spotlight"),
      properties = list(info),
      checkercolor = list(NA_real_),
      gradient_color = list(NA_real_),
      gradient_transpose = FALSE,
      world_gradient = FALSE,
      gradient_point_info = list(NA_real_),
      gradient_type = NA,
      noise = 0,
      noisephase = 0,
      noiseintensity = 0,
      noisecolor = list(c(0, 0, 0)),
      image = image_texture,
      image_repeat = list(image_repeat),
      alphaimage = "",
      lightintensity = intensity,
      fog = FALSE,
      fogdensity = 0.01,
      implicit_sample = importance_sample,
      sigma = 0,
      glossyinfo = list(NA_real_),
      bump_texture = "",
      bump_intensity = 1,
      roughness_texture = ""
    ))
  } else {
    info = c(info, invisible)
    ray_material(list(
      type = get_material_enum("light"),
      properties = list(info),
      checkercolor = list(NA_real_),
      gradient_color = list(gradient_color),
      gradient_transpose = gradient_transpose,
      world_gradient = is_world_gradient,
      gradient_point_info = list(gradient_point_info),
      gradient_type = gradient_type,
      noise = 0,
      noisephase = 0,
      noiseintensity = 0,
      noisecolor = list(c(0, 0, 0)),
      image = image_texture,
      image_repeat = list(image_repeat),
      alphaimage = "",
      lightintensity = intensity,
      fog = FALSE,
      fogdensity = 0.01,
      implicit_sample = importance_sample,
      sigma = 0,
      glossyinfo = list(NA_real_),
      bump_texture = "",
      bump_intensity = 1,
      roughness_texture = ""
    ))
  }
}

#' Glossy Material
#'
#' @param color Default `white`. The color of the surface. Can be either
#' a hexadecimal code, R color string, or a numeric rgb vector listing three intensities between `0` and `1`.
#' @param gloss Default `0.8`. Gloss of the surface, between `1` (completely glossy) and `0` (rough glossy).
#' Can be either a single number, or two numbers indicating an anisotropic distribution of normals (as in `microfacet()`).
#' @param reflectance Default `0.03`. The reflectivity of the surface. `1` is a full mirror, `0` is diffuse with a glossy highlight.
#' @param microfacet Default `tbr`.  Type of microfacet distribution. Alternative option `beckmann`.
#' @param checkercolor Default `NA`. If not `NA`, determines the secondary color of the checkered surface.
#' Can be either a hexadecimal code, or a numeric rgb vector listing three intensities between `0` and `1`.
#' @param checkerperiod Default `3`. The period of the checker pattern. Increasing this value makes the checker
#' pattern bigger, and decreasing it makes it smaller
#' @param noise Default `0`. If not `0`, covers the surface in a turbulent marble pattern. This value will determine
#' the amount of turbulence in the texture.
#' @param noisephase Default `0`. The phase of the noise. The noise will repeat at `360`.
#' @param noiseintensity Default `10`. Intensity of the noise.
#' @param noisecolor Default `#000000`. The secondary color of the noise pattern.
#' Can be either a hexadecimal code, or a numeric rgb vector listing three intensities between `0` and `1`.
#' @param gradient_color Default `NA`. If not `NA`, creates a secondary color for a linear gradient
#' between the this color and color specified in `color`. Direction is determined by `gradient_transpose`.
#' @param gradient_transpose Default `FALSE`. If `TRUE`, this will use the `v` coordinate texture instead
#' of the `u` coordinate texture to map the gradient.
#' @param gradient_point_start Default `NA`. If not `NA`, this changes the behavior from mapping texture coordinates to
#' mapping to world space coordinates. This should be a length-3 vector specifying the x,y, and z points where the gradient
#' begins with value `color`.
#' @param gradient_point_end Default `NA`. If not `NA`, this changes the behavior from mapping texture coordinates to
#' mapping to world space coordinates. This should be a length-3 vector specifying the x,y, and z points where the gradient
#' begins with value `gradient_color`.
#' @param gradient_type Default `hsv`. Colorspace to calculate the gradient. Alternative `rgb`.
#' @param image_texture Default `""`. A 3-layer RGB array or filename to be used as the texture on the surface of the object.
#' @param image_repeat Default `1`. Number of times to repeat the image across the surface.
#' `u` and `v` repeat amount can be set independently if user passes in a length-2 vector.
#' @param alpha_texture Default `""`. A matrix or filename (specifying a greyscale image) to be used to specify the transparency.
#' @param bump_texture Default `""`. A matrix, array, or filename (specifying a greyscale image) to
#' be used to specify a bump map for the surface.
#' @param bump_intensity Default `1`. Intensity of the bump map. High values may lead to unphysical results.
#' @param roughness_texture Default `""`. A matrix, array, or filename (specifying a greyscale image) to
#' be used to specify a roughness map for the surface.
#' @param roughness_range Default ` c(0.0001, 0.2)`. This is a length-2 vector that specifies the range of roughness values
#' that the `roughness_texture` can take.
#' @param roughness_flip Default `FALSE`. Setting this to `TRUE` flips the roughness values specified in the `roughness_texture`
#' so high values are now low values and vice versa.
#' @param importance_sample Default `FALSE`. If `TRUE`, the object will be sampled explicitly during
#' the rendering process. If the object is particularly important in contributing to the light paths
#' in the image (e.g. light sources, refracting glass ball with caustics, metal objects concentrating light),
#' this will help with the convergence of the image.
#'
#' @return Single row of a tibble describing the glossy material.
#' @export
#'
#'@examplesIf interactive() || identical(Sys.getenv("IN_PKGDOWN"), "true")
#' #Generate a glossy sphere
#' generate_ground(material=diffuse(sigma=90)) |>
#'   add_object(sphere(y=0.2,material=glossy(color="#2b6eff"))) |>
#'   add_object(sphere(y=2.8,material=light())) |>
#'   render_scene(parallel=TRUE,clamp_value=10,samples=16,sample_method="sobol_blue")
#' #Change the color of the underlying diffuse layer
#' generate_ground(material=diffuse(sigma=90)) |>
#'   add_object(sphere(y=0.2,x=-2.1,material=glossy(color="#fc3d03"))) |>
#'   add_object(sphere(y=0.2,material=glossy(color="#2b6eff"))) |>
#'   add_object(sphere(y=0.2,x=2.1,material=glossy(color="#2fed4f"))) |>
#'   add_object(sphere(y=8,z=-5,radius=3,material=light(intensity=20))) |>
#'   render_scene(parallel=TRUE,clamp_value=10,samples=16,fov=40,sample_method="sobol_blue")
#' #Change the amount of gloss
#' generate_ground(material=diffuse(sigma=90)) |>
#'   add_object(sphere(y=0.2,x=-2.1,material=glossy(gloss=1,color="#fc3d03"))) |>
#'   add_object(sphere(y=0.2,material=glossy(gloss=0.5,color="#2b6eff"))) |>
#'   add_object(sphere(y=0.2,x=2.1,material=glossy(gloss=0,color="#2fed4f"))) |>
#'   add_object(sphere(y=8,z=-5,radius=3,material=light(intensity=20))) |>
#'   render_scene(parallel=TRUE,clamp_value=10,samples=16,fov=40,sample_method="sobol_blue")
#' #Add gloss to a pattern
#' generate_ground(material=diffuse(sigma=90)) |>
#'   add_object(sphere(y=0.2,x=-2.1,material=glossy(noise=2,noisecolor="black"))) |>
#'   add_object(sphere(y=0.2,material=glossy(color="#ff365a",checkercolor="#2b6eff"))) |>
#'   add_object(sphere(y=0.2,x=2.1,material=glossy(color="blue",gradient_color="#2fed4f"))) |>
#'   add_object(sphere(y=8,z=-5,radius=3,material=light(intensity=20))) |>
#'   render_scene(parallel=TRUE,clamp_value=10,samples=16,fov=40,sample_method="sobol_blue")
#' #Add an R and a fill light
#' generate_ground(material=diffuse()) |>
#'   add_object(sphere(y=0.2,material=glossy(color="#2b6eff",reflectance=0.05))) |>
#'   add_object(obj_model(r_obj(simple_r = TRUE),
#'                        z=-1,y=-0.05,scale=0.45,material=diffuse())) |>
#'   add_object(sphere(y=6,z=-1,radius=4,material=light(intensity=3))) |>
#'   add_object(sphere(z=-15,material=light(intensity=50))) |>
#'   render_scene(parallel=TRUE,clamp_value=10,samples=16,sample_method="sobol_blue")
glossy = function(
  color = "white",
  gloss = 1,
  reflectance = 0.05,
  microfacet = "tbr",
  checkercolor = NA,
  checkerperiod = 3,
  noise = 0,
  noisephase = 0,
  noiseintensity = 10,
  noisecolor = "#000000",
  gradient_color = NA,
  gradient_transpose = FALSE,
  gradient_point_start = NA_real_,
  gradient_point_end = NA_real_,
  gradient_type = "hsv",
  image_texture = "",
  image_repeat = 1,
  alpha_texture = "",
  bump_texture = "",
  bump_intensity = 1,
  roughness_texture = "",
  roughness_range = c(0.0001, 0.2),
  roughness_flip = FALSE,
  importance_sample = FALSE
) {
  microtype = switch(microfacet, "tbr" = 1, "beckmann" = 2, 1)
  gloss[gloss <= 0] = 0
  gloss[gloss > 1] = 1
  gloss = 1 - gloss
  gloss = gloss / 2
  if (length(gloss) == 1) {
    alphax = gloss^2
    alphay = gloss^2
  } else {
    alphax = gloss[1]^2
    alphay = gloss[2]^2
  }
  if (length(roughness_range) != 2) {
    stop("length of roughness_range must be 2")
  }
  if (roughness_range[1] > roughness_range[2]) {
    roughness_range = rev(roughness_range)
  }
  if (
    roughness_range[1] == roughness_range[2] && nchar(roughness_texture) > 0
  ) {
    roughness_texture = ""
    gloss = 1 - roughness_range[1]
  }
  color = convert_color(color)
  reflectance = rep(reflectance, 3)
  if (all(!is.na(checkercolor))) {
    checkercolor = convert_color(checkercolor)
  } else {
    checkercolor = NA_real_
  }
  if (all(!is.na(gradient_color))) {
    gradient_color = convert_color(gradient_color)
  } else {
    gradient_color = NA_real_
  }
  if (
    !any(is.na(gradient_point_start)) &&
      !any(is.na(gradient_point_end)) &&
      !any(is.na(gradient_color))
  ) {
    stopifnot(length(gradient_point_start) == 3)
    stopifnot(length(gradient_point_end) == 3)
    stopifnot(is.numeric(gradient_point_start))
    stopifnot(is.numeric(gradient_point_end))
    gradient_point_info = c(gradient_point_start, gradient_point_end)
    is_world_gradient = TRUE
  } else {
    is_world_gradient = FALSE
    gradient_point_info = NA_real_
  }
  noisecolor = convert_color(noisecolor)
  image_texture = check_image_texture(image_texture)
  alpha_texture = check_image_texture(alpha_texture)
  bump_texture = check_image_texture(bump_texture)
  roughness_texture = check_image_texture(roughness_texture)

  if (length(image_repeat) == 1) {
    image_repeat = c(image_repeat, image_repeat)
  }
  roughness_flip = ifelse(roughness_flip, 1, 0)

  glossyinfo = list(c(
    microtype,
    alphax,
    alphay,
    reflectance,
    c(1, 1, 1),
    roughness_range,
    roughness_flip
  ))
  ray_material(list(
    type = get_material_enum("glossy"),
    properties = list(c(color)),
    gradient_color = list(gradient_color),
    gradient_transpose = FALSE,
    world_gradient = is_world_gradient,
    gradient_point_info = list(gradient_point_info),
    gradient_type = gradient_type,
    checkercolor = list(c(checkercolor, checkerperiod)),
    noise = noise,
    noisephase = noisephase * pi / 180,
    noiseintensity = noiseintensity,
    noisecolor = list(noisecolor),
    image = image_texture,
    image_repeat = list(image_repeat),
    alphaimage = alpha_texture,
    lightintensity = NA_real_,
    fog = FALSE,
    fogdensity = NA_real_,
    implicit_sample = importance_sample,
    sigma = 0,
    glossyinfo = glossyinfo,
    bump_texture = bump_texture,
    bump_intensity = bump_intensity,
    roughness_texture = roughness_texture
  ))
}


SigmaAFromConcentration = function(ce, cp) {
  eumelaninSigmaA = c(0.419, 0.697, 1.37)
  pheomelaninSigmaA = c(0.187, 0.4, 1.05)
  sigma_a = ce * eumelaninSigmaA + cp * pheomelaninSigmaA
  return(sigma_a)
}

SigmaAFromReflectance = function(c, beta_n) {
  sigma_a = (log(c) /
    (5.969 -
      0.215 * beta_n +
      2.532 * (beta_n)^2 -
      10.73 * (beta_n)^3 +
      5.574 * (beta_n)^4 +
      0.245 * (beta_n)^5))^2
  return(sigma_a)
}

#' Hair Material
#'
#' @param pigment Default `1.3`. Concentration of the eumelanin pigment in the hair. Blonde hair has concentrations around 0.3, brown around 1.3, and black around 8.
#' @param red_pigment Default `0`.Concentration of the pheomelanin pigment in the hair. Pheomelanin makes red hair red.
#' @param color Default `NA`. Approximate color. Overrides `pigment`/`redness` arguments.
#' @param sigma_a Default `NA`. Attenuation. Overrides `color` and `pigment`/`redness` arguments.
#' @param eta Default `1.55`. Index of refraction of the hair medium.
#' @param beta_m Default `0.3`. Longitudinal roughness of the hair. Should be between 0 and 1. This roughness controls the size and shape of the hair highlight.
#' @param beta_n Default `0.3`. Azimuthal roughness of the hair. Should be between 0 and 1.
#' @param alpha Default `2`. Angle of scales on the hair surface, in degrees.
#'
#' @return Single row of a tibble describing the hair material.
#' @export
#' @importFrom  grDevices col2rgb
#'
#'@examplesIf interactive() || identical(Sys.getenv("IN_PKGDOWN"), "true")
#' #Create a hairball
#' #Generate rendom points on a sphere
#' lengthval = 0.5
#' theta = acos(2*runif(10000)-1.0);
#' phi = 2*pi*(runif(10000))
#' bezier_list = list()
#'
#' #Grow the hairs
#' for(i in 1:length(phi)) {
#'   pointval = c(sin(theta[i]) * sin(phi[i]),
#'                cos(theta[i]),
#'                sin(theta[i]) * cos(phi[i]))
#'   bezier_list[[i]] = bezier_curve(width=0.01, width_end=0.008,
#'                                   p1 = pointval,
#'                                   p2 = (1+(lengthval*0.33))*pointval,
#'                                   p3 = (1+(lengthval*0.66))*pointval,
#'                                   p4 = (1+(lengthval)) * pointval,
#'                                   material=hair(pigment = 0.3, red_pigment = 1.3,
#'                                                 beta_m = 0.3, beta_n= 0.3),
#'                                   type="flat")
#' }
#' hairball = dplyr::bind_rows(bezier_list)
#'
#' generate_ground(depth=-2,material=diffuse(color="grey20")) |>
#'   add_object(sphere()) |>
#'   add_object(hairball) |>
#'   add_object(sphere(y=20,z=20,radius=5,material=light(color="white",intensity = 100))) |>
#'   render_scene(samples=16, lookfrom=c(0,3,10),clamp_value = 10,
#'                fov=20, width=800, height=800)
#'
#' #Specify the color directly and increase hair roughness
#' for(i in 1:length(phi)) {
#'   pointval = c(sin(theta[i]) * sin(phi[i]),
#'                cos(theta[i]),
#'                sin(theta[i]) * cos(phi[i]))
#'   bezier_list[[i]] = bezier_curve(width=0.01, width_end=0.008,
#'                                   p1 = pointval,
#'                                   p2 = (1+(lengthval*0.33))*pointval,
#'                                   p3 = (1+(lengthval*0.66))*pointval,
#'                                   p4 = (1+(lengthval)) * pointval,
#'                                   material=hair(color="purple",
#'                                                 beta_m = 0.5, beta_n= 0.5),
#'                                   type="flat")
#' }
#' hairball = dplyr::bind_rows(bezier_list)
#' generate_ground(depth=-2,material=diffuse(color="grey20")) |>
#'   add_object(sphere()) |>
#'   add_object(hairball) |>
#'   add_object(sphere(y=20,z=20,radius=5,material=light(color="white",intensity = 100))) |>
#'   render_scene(samples=16, lookfrom=c(0,3,10),clamp_value = 10,
#'                fov=20, width=800, height=800)
hair = function(
  pigment = 1.3,
  red_pigment = 0,
  color = NA,
  sigma_a = NA,
  eta = 1.55,
  beta_m = 0.3,
  beta_n = 0.3,
  alpha = 2
) {
  if (!is.na(sigma_a)) {
    sigma_a = sigma_a
  } else if (!is.na(color)) {
    sigma_a = SigmaAFromReflectance(convert_color(color), beta_n)
  } else {
    stopifnot(pigment >= 0)
    stopifnot(red_pigment >= 0)
    sigma_a = SigmaAFromConcentration(pigment, red_pigment)
  }

  info = c(sigma_a, eta, beta_m, beta_n, alpha)
  ray_material(list(
    type = get_material_enum("hair"),
    properties = list(info),
    checkercolor = list(NA_real_),
    gradient_color = list(NA_real_),
    gradient_transpose = NA,
    world_gradient = FALSE,
    gradient_point_info = list(NA_real_),
    gradient_type = NA,
    noise = 0,
    noisephase = 0,
    noiseintensity = 0,
    noisecolor = list(c(0, 0, 0)),
    image = "",
    image_repeat = list(NA_real_),
    alphaimage = "",
    lightintensity = NA_real_,
    fog = FALSE,
    fogdensity = NA_real_,
    implicit_sample = FALSE,
    sigma = NA_real_,
    glossyinfo = list(NA_real_),
    bump_texture = "",
    bump_intensity = NA_real_,
    roughness_texture = ""
  ))
}

#' Lambertian Material (deprecated)
#'
#' @param ... Arguments to pass to diffuse() function.
#'
#' @return Single row of a tibble describing the diffuse material.
#' @export
#' @importFrom  grDevices col2rgb
#'
#'@examplesIf interactive() || identical(Sys.getenv("IN_PKGDOWN"), "true")
#' #Deprecated lambertian material. Will display a warning.
#' scene = generate_cornell() |>
#'   add_object(sphere(x=555/2,y=555/2,z=555/2,radius=555/8,material=lambertian()))
#'   render_scene(scene, lookfrom=c(278,278,-800),lookat = c(278,278,0), samples=16,
#'              aperture=0, fov=40, ambient_light=FALSE, parallel=TRUE)
lambertian = function(...) {
  warning("lambertian() deprecated--use diffuse() instead.")
  diffuse(...)
}

#' Check Image Texture
#' @keywords internal
check_image_texture = function(image_texture) {
  if (!is.array(image_texture) && !is.character(image_texture)) {
    image_texture = ""
    warning(
      "Texture not in recognized format (array, matrix, or filename), ignoring."
    )
  }
  if (
    !is.array(image_texture) &&
      nchar(image_texture) > 0 &&
      !tools::file_ext(tolower(image_texture)) %in%
        c("jpg", "jpeg", "png", "exr", "hdr")
  ) {
    image_texture = ""
    warning(
      "Texture not in recognized format (JPEG, PNG, EXR,or HDR), ignoring."
    )
  }
  return(image_texture)
}

#' get_material_enum
#' @keywords internal
get_material_enum = function(material) {
  switch(
    material,
    "diffuse" = 1L,
    "metal" = 2L,
    "dielectric" = 3L,
    "oren-nayar" = 4L,
    "light" = 5L,
    "mf" = 6L,
    "glossy" = 7L,
    "spotlight" = 8L,
    "hair" = 9L,
    "mf-t" = 10L,
    stop(sprintf("Material type `%s` not found", material))
  )
}

#' get_material_name
#' @keywords internal
get_material_name = function(material) {
  c(
    "diffuse",
    "metal",
    "dielectric",
    "oren-nayar",
    "light",
    "mf",
    "glossy",
    "spotlight",
    "hair",
    "mf-t"
  )[material]
}