JuliaReinforcementLearning · landrumb · Oct 10, 2020 · Oct 10, 2020 · Oct 10, 2020 · Oct 10, 2020
diff --git a/src/abstract_grid_world.jl b/src/abstract_grid_world.jl
@@ -32,5 +32,3 @@ get_actions(w::AbstractGridWorld) = (MOVE_FORWARD, TURN_LEFT, TURN_RIGHT)
 
 get_agent_view_inds(w::AbstractGridWorld, s=(7,7)) = get_agent_view_inds(get_agent_pos(w).I, s, get_agent_dir(w))
 
-get_agent_view!(v::BitArray{3}, w::AbstractGridWorld) = get_agent_view!(v, convert(GridWorldBase, w), get_agent_pos(w), get_agent_dir(w))
-
diff --git a/src/grid_world_base.jl b/src/grid_world_base.jl
@@ -60,6 +60,54 @@ function Random.rand(f::Function, w::GridWorldBase; max_try=typemax(Int), rng=Ra
     return nothing
 end
 
+#####
+# Occlusion
+#####
+
+radius(x, y) = √(x^2 + y^2)
+radius(p::Tuple) = radius(p[1], p[2])
+theta(x, y) = x == 0 ? sign(y)*π/2 : atan(y, x)
+theta(p::Tuple) = theta(p[1], p[2])
+
+struct PolarCoord
+    θ::AbstractFloat
+    r::AbstractFloat
+end
+PolarCoord(θ::Real, r::Real) = PolarCoord((θ + (r<0 && π)) % 2π, abs(r))
+PolarCoord(p::Tuple) = PolarCoord(theta(p), radius(p))
+PolarCoord(p::CartesianIndex) = PolarCoord(Tuple(p))
+
+struct Shadow
+    minθ::AbstractFloat
+    maxθ::AbstractFloat
+    r::AbstractFloat
+end
+function Shadow(p::CartesianIndex)
+    r = radius(Tuple(p))
+    corners = [(p[1]+x, p[2]+y) for x in -.5:.5, y in -.5:.5]
+    corners = theta.(corners)
+    Shadow(minimum(corners), maximum(corners), r)
+end
+
+"""
+returns a 2D array of boolean values, where `true` represents an index which is
+occluded by the shadow `s` evaluating `v`
+"""
+function (s::Shadow)(v::CartesianIndices)
+    polar = PolarCoord.(v)``
+    f(x) = x.r > s.r && s.minθ <= x.θ <= s.maxθ
+    f.(polar)
+end
+
+function shadowmap(m::Matrix{Bool})
+    indices = CartesianIndices(((-1*size(m)[1]÷2):(size(m)[1]÷2), 0:(size(m)[2]-1)))
+    shadows = Shadow.(indices[m])
+    output = fill(false, size(a))
+    for s in shadows
+        output |= s(indices)
+    end
+    output
+end
 #####
 # get_agent_view
 #####
@@ -74,14 +122,46 @@ ind_map((i,j), (m, n), ::Right) = (j, n-i+1)
 ind_map((i,j), (m, n), ::Up) = (m-i+1, n-j+1)
 ind_map((i,j), (m, n), ::Down) = (i,j)
 
-function get_agent_view!(v::AbstractArray{Bool,3}, a::AbstractArray{Bool,3}, p::CartesianIndex, dir::LRUD)
+"""
+Updates the agent view
+
+Args:
+    v::AbstractArray{Bool,3}: the current agent view as a 3D array with indices [type, x, y]
+    a::AbstractArray{Bool,3}: the current environment as a 3D array with indices [type, x, y]
+    p::CartesianIndex: location of the agent
+    dir::LRUD: direction the agent is looking
+"""
+function get_agent_view!(v::AbstractArray{Bool,3}, w::AbstractGridWorld; perspective::Bool=true)
+    a = convert(GridWorldBase, w)
+    p = get_agent_pos(w)
+    dir = get_agent_dir(w)
+
     view_size = (size(v, 2), size(v, 3))
     grid_size = (size(a,2),size(a,3))
-    inds = get_agent_view_inds(p.I, view_size, dir)
-    valid_inds = CartesianIndices(grid_size)
-    for ind in CartesianIndices(inds)
-        if inds[ind] ∈ valid_inds
-            v[:, ind_map(ind.I, view_size, dir)...] .= a[:, inds[ind]]
+    inds = get_agent_view_inds(p.I, view_size, dir) # indices of the visible points
+    valid_inds = CartesianIndices(grid_size) # CartesianIndices representing the whole environment
+
+    if perspective
+        m = convert(Matrix{Bool}, copy(v))
+        shadows = []
+        for ind in CartesianIndices(inds) # for every index in view...
+            if inds[ind] ∈ valid_inds # if it's within the environment...
+                o = findfirst(w[:, inds[ind]]) # first object at the index
+                m[ind_map(ind.I, view_size, dir)...] .= isnothing(o) ? false : isopaque(w.objects[o]) <: Opaque
+            end
+        end
+        shadows = .!(shadowmap(m))
+        for ind in CartesianIndices(inds)
+            if inds[ind] ∈ valid_inds && shadows[ind_map(ind.I, view_size, dir)...]
+                v[:, ind_map(ind.I, view_size, dir)...] .= a[:, inds[ind]]
+            end
+        end
+    else
+        for ind in CartesianIndices(inds) # for every index in view...
+            if inds[ind] ∈ valid_inds # if it's within the environment...
+                # set its corresponding value in the view to the value in the environment
+                v[:, ind_map(ind.I, view_size, dir)...] .= a[:, inds[ind]]
+            end
         end
     end
     v

diff --git a/src/objects.jl b/src/objects.jl
@@ -30,8 +30,10 @@ const GOAL = Goal()
 Base.convert(::Type{Char}, ::Goal) = '♥'
 get_color(::Goal) = :red
 
-struct Door{C} <: AbstractObject end
-Door(c) = Door{c}()
+struct Door{C} <: AbstractObject
+    open::Bool
+end
+Door(c) = Door{c}(false)
 Base.convert(::Type{Char}, ::Door) = '⩎'
 get_color(::Door{C}) where C = C
 
@@ -84,6 +86,16 @@ istransportable(::Type{<:Key}) = TRANSPORTABLE
 istransportable(::Type{Gem}) = TRANSPORTABLE
 istransportable(x::AbstractObject) = istransportable(typeof(x))
 
+struct Opaque end
+struct Transparent end
+const OPAQUE = Opaque()
+const TRANSPARENT = Transparent()
+isopaque(::Type{<:AbstractObject}) = OPAQUE
+isopaque(::Type{<:Key}) = TRANSPARENT
+isopaque(::Type{Gem}) = TRANSPARENT
+isopaque(x::AbstractObject) = isopaque(typeof(x))
+isopaque(x<:Door) = x.open ? TRANSPARENT : OPAQUE
+
 (x::Pickup)(a::Agent, o) = x(istransportable(o), a, o)
 
 function (::Pickup)(::Transportable, a::Agent, o::AbstractObject) 

diff --git a/test/runtests.jl b/test/runtests.jl
@@ -28,4 +28,21 @@ ACTIONS = [TURN_LEFT, TURN_RIGHT, MOVE_FORWARD]
             end
         end
     end
+    @testset "grid_world_base.jl" begin
+        grid = CartesianIndices((-3:3, 0:6))
+        soln = 
+        [[1,1,1,1,1,1,1]
+         [1,1,1,1,1,1,1]
+         [1,1,1,1,1,1,1]
+         [1,1,1,1,1,1,1]
+         [1,1,1,1,0,0,1]
+         [0,0,1,1,0,0,1]
+         [0,1,1,1,0,0,0]]
+
+        s = GridWorlds.Shadow(CartesianIndex((1,3)))
+        println("minθ:$(s.minθ)|maxθ:$(s.maxθ)|r:$(s.r)")
+        println(s(grid))
+        println("($(GridWorlds.theta(3,4)), $(GridWorlds.radius(3,4)))")
+        println(s(CartesianIndices((3:3, 5:5))))
+    end
 end
Original file line number	Diff line number	Diff line change
Expand Up		@@ -32,5 +32,3 @@ get_actions(w::AbstractGridWorld) = (MOVE_FORWARD, TURN_LEFT, TURN_RIGHT)

		get_agent_view_inds(w::AbstractGridWorld, s=(7,7)) = get_agent_view_inds(get_agent_pos(w).I, s, get_agent_dir(w))

		get_agent_view!(v::BitArray{3}, w::AbstractGridWorld) = get_agent_view!(v, convert(GridWorldBase, w), get_agent_pos(w), get_agent_dir(w))