From a3b1f4920c24c401c240308582009f28580bc9fe Mon Sep 17 00:00:00 2001
From: Aaron Fenyes <aaron.fenyes@fareycircles.ooo>
Date: Wed, 26 Jun 2024 00:41:21 -0700
Subject: [PATCH] Build construction viewer module

---
 engine-proto/ConstructionViewer.jl    | 123 ++++++++++++++++++++++++++
 engine-proto/ganja-test/ganja-test.jl |   2 +-
 2 files changed, 124 insertions(+), 1 deletion(-)
 create mode 100644 engine-proto/ConstructionViewer.jl

diff --git a/engine-proto/ConstructionViewer.jl b/engine-proto/ConstructionViewer.jl
new file mode 100644
index 0000000..efa7293
--- /dev/null
+++ b/engine-proto/ConstructionViewer.jl
@@ -0,0 +1,123 @@
+module Viewer
+
+using Blink
+using Colors
+
+export ConstructionViewer, display!
+
+# === Blink utilities ===
+
+append_to_head!(w, type, content) = @js w begin
+  @var element = document.createElement($type)
+  element.appendChild(document.createTextNode($content))
+  document.head.appendChild(element)
+end
+
+style!(w, stylesheet) = append_to_head!(w, "style", stylesheet)
+
+script!(w, code) = append_to_head!(w, "script", code)
+
+# === construction viewer ===
+
+mutable struct ConstructionViewer
+  win::Window
+  
+  function ConstructionViewer()
+    # create window and open developer console
+    win = Window()
+    opentools(win)
+    
+    # set stylesheet
+    style!(win, """
+      /* needed to keep Ganja canvas from blowing up */
+      canvas {
+        min-width: 600px;
+        max-width: 600px;
+        min-height: 600px;
+        max-height: 600px;
+      }
+    """)
+    
+    # load Ganja.js
+    loadjs!(win, "https://unpkg.com/ganja.js")
+    
+    # create global functions and variables
+    script!(win, """
+      // create algebra
+      var CGA3 = Algebra(4, 1);
+      
+      // initialize element list and palette
+      var elements = [];
+      var palette = [];
+      
+      // declare visualization handle
+      var graph;
+      
+      // create scene function
+      function scene() {
+        commands = [];
+        for (let n = 0; n < elements.length; ++n) {
+          commands.push(palette[n], elements[n]);
+        }
+        return commands;
+      }
+    """)
+    
+    # create view
+    @js win begin
+      graph = CGA3.graph(
+        scene,
+        Dict(
+          "conformal" => true,
+          "gl" => true,
+          "grid" => true
+        )
+      )
+      document.body.replaceChildren(graph)
+    end
+    
+    new(win)
+  end
+end
+
+function display!(viewer::ConstructionViewer, elements::Matrix)
+  # load elements
+  elements_full = [
+    [0; elt; fill(0, 26)]
+    for elt in eachcol(elements)
+  ]
+  @js viewer.win elements = $elements_full.map((elt) -> @new CGA3(elt))
+  
+  # generate palette. this is Gadfly's `default_discrete_colors` palette,
+  # available under the MIT license
+  palette = distinguishable_colors(
+    length(elements_full),
+    [LCHab(70, 60, 240)],
+    transform = c -> deuteranopic(c, 0.5),
+    lchoices = Float64[65, 70, 75, 80],
+    cchoices = Float64[0, 50, 60, 70],
+    hchoices = range(0, stop=330, length=24)
+  )
+  palette_packed = [RGB24(c).color for c in palette]
+  @js viewer.win palette = $palette_packed
+  
+  # update view
+  @js viewer.win requestAnimationFrame(graph.update.bind(graph, scene));
+end
+
+end
+
+# ~~~ sandbox setup ~~~
+
+# in the default view, e4 + e5 is the point at infinity
+elements = sqrt(0.5) * BigFloat[
+  1  1 -1 -1  0;
+  1 -1  1 -1  0;
+  1 -1 -1  1  0;
+  0  0  0  0 -sqrt(6);
+  1  1  1  1  2
+]
+
+# show construction
+viewer = Viewer.ConstructionViewer()
+Viewer.display!(viewer, elements)
\ No newline at end of file
diff --git a/engine-proto/ganja-test/ganja-test.jl b/engine-proto/ganja-test/ganja-test.jl
index 19578bd..6c55061 100644
--- a/engine-proto/ganja-test/ganja-test.jl
+++ b/engine-proto/ganja-test/ganja-test.jl
@@ -3,7 +3,7 @@ using Colors
 
 # === utilities ===
 
-append_to_head!(w, type, content) = @js win begin
+append_to_head!(w, type, content) = @js w begin
   @var element = document.createElement($type)
   element.appendChild(document.createTextNode($content))
   document.head.appendChild(element)