Rendering different clusters of points with different colors

[ghost]

Hi,

First of all, thank you for the great package!
I would like to visualize single-cell RNA-seq data with rayshader.
In short, there are multiple clusters of points with different colors, and I want them to "jump out" based on the density of cells using geom_bin2d. In short, I have only been able to render one red cluster, but not a blue cluster in the same plot.

Here is a reproducible toy example, adapted from this Stack Overflow post:

library(tidyverse)
library(rayshader)

dfA <- data.frame(x=rnorm(50000, mean=5),  y=rnorm(50000, mean=5))
dfB <- data.frame(x=rnorm(30000, mean=25), y=rnorm(30000, mean=25))

p1 <- ggplot() + theme_bw() +
  geom_bin2d(data=dfA, aes(x=x, y=y), bins=100) +
  scale_fill_gradient(low="white", high="red")

p2 <- ggplot() + theme_bw() +
  geom_bin2d(data=dfB, aes(x=x, y=y), bins=100) + 
  scale_fill_gradient(low="white", high="blue")

p.combined <- ggplot(data = layer_data(p1),
                     aes(x = x, y = y, fill = fill)) +
  geom_tile() +
  geom_tile(data = layer_data(p2)) +
  scale_fill_identity() +
  theme(legend.position = "none", 
        axis.line=element_blank(), 
        axis.text.x=element_blank(), axis.title.x=element_blank(),
        axis.text.y=element_blank(), axis.title.y=element_blank(),
        axis.ticks=element_blank(), 
        panel.background = element_blank())

p.combined looks like this:

But then I try to render it using rayshader:

plot_gg(p.combined, multicore=TRUE,width=10,height=10,scale=400, windowsize=c(1000, 866),
        offset_edges = TRUE, shadow_intensity = 0.9, shadowcolor = "#3a4f70", lambert=TRUE)

and only one of the clusters renders in 3D, the other stays flat:

Perhaps I'm missing something within ggplot or rayshader, and the solution is simple. It probably has to do with using geom_tile(). Any help would be appreciated!