arrow {rayrender}

Arrow Object

Description

Composite object (cone + segment)

Usage

arrow(
  start = c(0, 0, 0),
  end = c(0, 1, 0),
  radius_top = 0.2,
  radius_tail = 0.1,
  tail_proportion = 0.5,
  direction = NA,
  from_center = TRUE,
  material = diffuse(),
  flipped = FALSE,
  scale = c(1, 1, 1)
)

Arguments

start

Default 'c(0, 0, 0)'. Base of the arrow, specifying 'x', 'y', 'z'.

end

Default 'c(0, 1, 0)'. Tip of the arrow, specifying 'x', 'y', 'z'.

radius_top

Default '0.5'. Radius of the top of the arrow.

radius_tail

Default '0.2'. Radius of the tail of the arrow.

tail_proportion

Default '0.5'. Proportion of the arrow that is the tail.

direction

Default 'NA'. Alternative to 'start' and 'end', specify the direction (via a length-3 vector) of the arrow. Arrow will be centered at 'start', and the length will be determined by the magnitude of the direction vector.

from_center

Default 'TRUE'. If orientation specified via 'direction', setting this argument to 'FALSE' will make 'start' specify the bottom of the cone, instead of the middle.

material

Default diffuse.The material, called from one of the material functions diffuse, metal, or dielectric.

flipped

Default 'FALSE'. Whether to flip the normals.

scale

Default 'c(1, 1, 1)'. Scale transformation in the x, y, and z directions. If this is a single value, number, the object will be scaled uniformly. Notes: this will change the stated start/end position of the cone. Emissive objects may not currently function correctly when scaled.

Value

Single row of a tibble describing the cone in the scene.

Examples

#Draw a simple arrow from x = -1 to x = 1
if(run_documentation()) {
generate_studio() %>% 
  add_object(arrow(start = c(-1,0,0), end = c(1,0,0), material=glossy(color="red"))) %>% 
  add_object(sphere(y=5,material=light(intensity=20))) %>% 
  render_scene(clamp_value=10,  samples=128)
}
if(run_documentation()) {
#Change the proportion of tail to top
generate_studio(depth=-2) %>% 
  add_object(arrow(start = c(-1,-1,0), end = c(1,-1,0), tail_proportion = 0.5,
                   material=glossy(color="red"))) %>% 
  add_object(arrow(start = c(-1,0,0), end = c(1,0,0), tail_proportion = 0.75,
                   material=glossy(color="red"))) %>% 
  add_object(arrow(start = c(-1,1,0), end = c(1,1,0), tail_proportion = 0.9,
                   material=glossy(color="red"))) %>% 
  add_object(sphere(y=5,z=5,x=2,material=light(intensity=30))) %>% 
  render_scene(clamp_value=10, fov=25,  samples=128)
}
if(run_documentation()) {
#Change the radius of the tail/top segments
generate_studio(depth=-1.5) %>% 
  add_object(arrow(start = c(-1,-1,0), end = c(1,-1,0), tail_proportion = 0.75,
                   radius_top = 0.1, radius_tail=0.03,
                   material=glossy(color="red"))) %>% 
  add_object(arrow(start = c(-1,0,0), end = c(1,0,0), tail_proportion = 0.75,
                   radius_top = 0.2, radius_tail=0.1,
                   material=glossy(color="red"))) %>% 
  add_object(arrow(start = c(-1,1,0), end = c(1,1,0), tail_proportion = 0.75,
                   radius_top = 0.3, radius_tail=0.2,
                   material=glossy(color="red"))) %>% 
  add_object(sphere(y=5,z=5,x=2,material=light(intensity=30))) %>% 
  render_scene(clamp_value=10, samples=128)
}
if(run_documentation()) {
#We can also specify arrows via a midpoint and direction:
generate_studio(depth=-1) %>% 
  add_object(arrow(start = c(-1,-0.5,0), direction = c(0,0,1),
                   material=glossy(color="green"))) %>% 
  add_object(arrow(start = c(1,-0.5,0), direction = c(0,0,-1),
                   material=glossy(color="red"))) %>% 
  add_object(arrow(start = c(0,-0.5,1), direction = c(1,0,0),
                   material=glossy(color="yellow"))) %>% 
  add_object(arrow(start = c(0,-0.5,-1), direction = c(-1,0,0),
                   material=glossy(color="purple"))) %>% 
  add_object(sphere(y=5,z=5,x=2,material=light(intensity=30))) %>% 
  render_scene(clamp_value=10, samples=128, 
               lookfrom=c(0,5,10), lookat=c(0,-0.5,0), fov=16)
}
if(run_documentation()) {
#Plot a 3D vector field for a gravitational well:

r = 1.5
theta_vals = seq(0,2*pi,length.out = 16)[-16]
phi_vals = seq(0,pi,length.out = 16)[-16][-1]
arrow_list = list()
counter = 1
for(theta in theta_vals) {
  for(phi in phi_vals) {
    rval = c(r*sin(phi)*cos(theta),r*cos(phi),r*sin(phi)*sin(theta)) 
    arrow_list[[counter]] = arrow(rval, direction = -1/2*rval/sqrt(sum(rval*rval))^3,
                                  tail_proportion = 0.66, radius_top=0.03, radius_tail=0.01,
                                  material = diffuse(color="red"))
    counter = counter + 1
  }
}
vector_field = do.call(rbind,arrow_list)
sphere(material=diffuse(noise=1,color="blue",noisecolor="darkgreen")) %>% 
  add_object(vector_field) %>% 
  add_object(sphere(y=0,x=10,z=5,material=light(intensity=200))) %>% 
  render_scene(fov=20, ambient=TRUE, samples=128,
               backgroundlow="black",backgroundhigh="white") 
}