NetLogo: How to make a turtle recognise any shade of one color? - netlogo

Question

I'm using NetLogo for the first time and need to lay out a simple programme where i have one light source that diffuses light out beyond its source patch and one turtle that will avoid the light.
I can achieve this by using basic 'set pcolor yellow' and then use 'if patch-ahead [pcolor] = yellow [right 45][fd speed]' type command. However this doesn't give me diffused light.
By adapting the HeatBugs code, i can diffuse the color out past the source patch, however the roaming turtle no longer recognises the color as yellow, i think, as it is a scale-color. I tried setting the code to != black but this also doesn't work. I'm assuming it's because the patches are being recolored after each tick.
Is there a way to make the turtle recognise the patches of diffused color so as to avoid them? Or a simpler way to diffuse the light out. (i want a variable intensity so using neighbors and yellow -1 won't do it.)
Here's the code i have so far: (this is a condensed version as i have other things happening in the main body, so i apologise if it isn't clear)
globals [ color-by-unhappiness? ]
turtles-own[
speed
speed-limit
speed-min
ideal-temp ;; The temperature I want to be at
output-heat ;; How much heat I emit per time step
unhappiness ;; The magnitude of the difference between my ideal
;; temperature and the actual current temperature here
]
patches-own[
temp
]
to setup
clear-all
setup-turtles
;;creating diffused light
set color-by-unhappiness? false ;; button
ask n-of number-of-lights patches [
sprout 1 [
set color white
set shape "circle"
set ideal-temp min-ideal-temp + random (max-ideal-temp - min- ideal-temp) ;;these are all sliders
set output-heat min-output-heat + random (max-output-heat - min- output-heat) ;;these are all sliders
set unhappiness abs (ideal-temp - temp) ;;ideal-temp is a button
color-by-ideal-temp
set size 2
]
]
reset-ticks
end
to setup-turtles
create-fears number-of-fears [
set color violet
set shape "circle"
setxy random-xcor random-ycor
set speed 0.1 + random-float 0.9
set speed-limit 1
set speed-min 0.00
]
end
to go
ask turtles [
if speed > speed-limit [set speed speed-limit]
fd speed
ask fears[
if patch-ahead 1 = nobody [rt 135]
if patch-right-and-ahead 45 1 != nobody and [pcolor] of patch-right-and-ahead 45 1 != black[left 45]
if patch-left-and-ahead 45 1 != nobody and [pcolor] of patch-left-and-ahead 45 1 != black[right 45]
ifelse [pcolor] of patch-here = yellow [set speed speed-min][fd speed]
]
if not any? turtles [ stop ]
;; diffuse heat through world
diffuse temp diffusion-rate
ask patches [ set temp temp * (1 - evaporation-rate) ]
ask turtles [ set temp temp + output-heat ask bugs [bug-move patch-here]]
recolor-turtles
recolor-patches
tick
end
to recolor-patches
ask patches [ set pcolor scale-color yellow temp 0 150 ]
]
end

Answer 1

I can't use your code as-is; check out the MCVE guidelines for some tips on reducing your code to just the necessary parts.
Color in Netlogo can given as a string, but it's also just a range of numbers. If you look at Tools > Color Swatches, you will see that the range of "Yellow" colors corresponds roughly to 40 ~ 50. So if you want to, you can just have them evaluate patch color using a numerical range rather than the color name. So, using this unnecessarily complicated example setup:
patches-own [ light? temp]
to setup
ca
ask patches [
set light? false
]
ask n-of 5 patches [
set light? true
set temp 150
]
recolor-patches
crt 10 [
move-to one-of patches with [ not ( pcolor > 40 and pcolor < 49 ) ]
]
reset-ticks
end
to recolor-patches
ask n-of 3 patches with [ light? ] [
if temp < 20 [
set temp temp + random 20
]
]
repeat 5 [
diffuse temp 0.1
]
ask patches [
ifelse temp > 0.25 [
set temp temp - 0.005
] [
set temp 0
]
set pcolor scale-color yellow temp 0 15
]
end
You can ask your turtles to move and just avoid patches that fall in that numerical range:
to go
recolor-patches
ask turtles [
ifelse [pcolor] of patch-ahead 1 > 40 and [pcolor] of patch-ahead 1 < 49 [
let target min-one-of neighbors [pcolor]
if target != nobody [
face target
fd 1
]
] [
rt random 60 - 30
fd 1
]
]
tick
end
EDIT
As Seth Tisue pointed out, the shade-of? primitive can accomplish what the greater than / less than logical statement does:
to go
recolor-patches
ask turtles [
ifelse shade-of? ( [pcolor] of patch-ahead 1 ) yellow [
let target min-one-of neighbors [pcolor]
if target != nobody [
face target
fd 1
]
] [
rt random 60 - 30
fd 1
]
]
tick
end
However, this does require a slight modification to the recolor-patches procedure, as scale-color sets the base color to 40 (in the case of 'yellow'); just ask patches with that pcolor to set their color to black (0) so that movement works as expected here:
to recolor-patches
ask n-of 3 patches with [ light? ] [
if temp < 20 [
set temp temp + random 20
]
]
repeat 5 [
diffuse temp 0.1
]
ask patches [
ifelse temp > 0.25 [
set temp temp - 0.005
] [
set temp 0
]
set pcolor scale-color yellow temp 0 15
if pcolor = 40 [
set pcolor black
]
]
end