Fix camera observable caching and cleanup

CHANGELOG.md

@@ -6,6 +6,7 @@
 - Fixed bugs with format strings and add new features by switching to Format.jl [#3633](https://github.com/MakieOrg/Makie.jl/pull/3633).
 - Fixed an issue where CairoMakie would unnecessarily rasterize polygons [#3605](https://github.com/MakieOrg/Makie.jl/pull/3605).
 - Added `PointBased` conversion trait to `scatterlines` recipe [#3603](https://github.com/MakieOrg/Makie.jl/pull/3603).
+- Fixed a bug with line/text/scatter resolutions getting disconnected by `empty!()` in GLMakie and re-enabled camera caching. [#3640](https://github.com/MakieOrg/Makie.jl/pull/3640)
 - Multiple small fixes for `map_latest`, `WGLMakie` picking and `PlotSpec` [#3637](https://github.com/MakieOrg/Makie.jl/pull/3637).
 - Fixed PolarAxis `rticks` being incompatible with rich text. [#3615](https://github.com/MakieOrg/Makie.jl/pull/3615)
 

GLMakie/src/drawing_primitives.jl

@@ -142,12 +142,21 @@ function connect_camera!(plot, gl_attributes, cam, space = gl_attributes[:space]
         # Overwrite these, user defined attributes shouldn't use those!
         gl_attributes[key] = lift(identity, plot, getfield(cam, key))
     end
+
     get!(gl_attributes, :view) do
-        # get!(cam.calculated_values, Symbol("view_$(space[])")) do
-            return lift(plot, cam.view, space) do view, space
-                return is_data_space(space) ? view : Mat4f(I)
-            end
-        # end
+        return lift(cam.view, space) do _, space
+            return Makie.get_cached_matrix(cam, :view, space)
+        end
+    end
+    get!(gl_attributes, :projection) do
+        return lift(cam.projection, cam.pixel_space, space) do _, _, space
+            return Makie.get_cached_matrix(cam, :projection, space)
+        end
+    end
+    get!(gl_attributes, :projectionview) do
+        return lift(cam.projectionview, cam.pixel_space, space) do _, _, space
+            return Makie.get_cached_matrix(cam, :projectionview, space)
+        end
     end
 
     # for lighting
@@ -165,25 +174,17 @@ function connect_camera!(plot, gl_attributes, cam, space = gl_attributes[:space]
             return transpose(inv(v[i, i] * m[i, i]))
         end
     end
-    get!(gl_attributes, :projection) do
-        # return get!(cam.calculated_values, Symbol("projection_$(space[])")) do
-            return lift(plot, cam.projection, cam.pixel_space, space) do _, _, space
-                return Makie.space_to_clip(cam, space, false)
-            end
-        # end
-    end
-    get!(gl_attributes, :projectionview) do
-        # get!(cam.calculated_values, Symbol("projectionview_$(space[])")) do
-            return lift(plot, cam.projectionview, cam.pixel_space, space) do _, _, space
-                Makie.space_to_clip(cam, space, true)
-            end
-        # end
-    end
+
     # resolution in real hardware pixels, not scaled pixels/units
     get!(gl_attributes, :resolution) do
-        get!(cam.calculated_values, :resolution) do
-            return lift(*, plot, gl_attributes[:px_per_unit], cam.resolution)
-        end
+        # Note:
+        # robj cleanup deletes all uniforms so to avoid deleting the cached
+        # resolution we need to create a copy here.
+        # TODO closing the screen should delete the cached entry as px_per_unit
+        # could be different in the next screen
+        return lift(identity, get!(cam.calculated_values, :px_resolution) do
+            return lift(*, gl_attributes[:px_per_unit], cam.resolution)
+        end)
     end
 
     delete!(gl_attributes, :space)

GLMakie/test/unit_tests.jl

@@ -443,3 +443,25 @@ end
     im[3][] = zeros(RGBf, 25, 15) # larger size
     GLMakie.closeall()
 end
+
+@testset "Camera caching" begin
+    f=Figure(size=(200,200))
+    screen = display(f, visible = false)
+    ax=Axis(f[1,1])
+    lines!(ax,sin.(0.0:0.1:2pi))
+    text!(ax,10.0,0.0,text="sine wave")
+    expected_keys = [
+        :projection_data, :view_data, :projectionview_pixel, :projectionview_data,
+        :px_resolution, :projection_pixel, :view_pixel
+    ]
+    for key in expected_keys
+        @test haskey(ax.scene.camera.calculated_values, key)
+        @test !isempty(ax.scene.camera.calculated_values[key].inputs)
+    end
+    empty!(ax)
+    for key in expected_keys
+        @test haskey(ax.scene.camera.calculated_values, key)
+        @test !isempty(ax.scene.camera.calculated_values[key].inputs)
+    end
+    GLMakie.closeall()
+end

src/camera/camera.jl

@@ -123,3 +123,30 @@ function is_mouseinside(scene::Scene)
     #     is_mouseinside(child) && return false
     # end
 end
+
+function get_cached_obs(cam::Camera, name::Symbol, space::Symbol)
+    fullname = Symbol("$(name)_$(space)")
+    obs = get!(cam.calculated_values, fullname) do
+        # These run at max priority so they update before default priority
+        # listeners to projectionview etc are called.
+        if name == :view
+            return lift(cam.view, priority = typemax(Int)) do view
+                return is_data_space(space) ? view : Mat4f(I)
+            end
+        elseif name == :projection
+            return lift(cam.projection, cam.pixel_space, priority = typemax(Int)) do _, _
+                return Makie.space_to_clip(cam, space, false)
+            end
+        elseif name == :projectionview
+            return lift(cam.projectionview, cam.pixel_space, priority = typemax(Int)) do _, _
+                return Makie.space_to_clip(cam, space, true)
+            end
+        else
+            error("Cannot create a cached Observable for unrecognized camera matrix :$(name).")
+        end
+    end
+    return obs
+end
+@inline function get_cached_matrix(cam::Camera, name::Symbol, space::Symbol)
+    return get_cached_obs(cam, name, space)[]
+end