From f77b50cac98b6e9f77fcd1ffaebaf2e8ce75ddd3 Mon Sep 17 00:00:00 2001
From: TreetopFlyer <seth111@gmail.com>
Date: Sun, 11 Jul 2021 18:28:00 -0400
Subject: [PATCH] fixed missing neighbor bug

---
 index.html | 11 ++++---
 region.js  | 92 ++++++++++++++++++++++++++++++++++++------------------
 scene.js   |  2 +-
 3 files changed, 70 insertions(+), 35 deletions(-)

diff --git a/index.html b/index.html
index 28a637c..c214b72 100644
--- a/index.html
+++ b/index.html
@@ -26,13 +26,13 @@ import { Region } from "./region.js";
 let surfaceTest = () =>
 {
     let voxels = [];
-    voxels[Region.I(2, 2, 2)] = true;
-    voxels[Region.I(2, 3, 2)] = true;
+    voxels[Region.I(0, 0, 0)] = true;
+    voxels[Region.I(1, 0, 0)] = true;
     let surface = Region.Surface(voxels)
     console.log(surface);
 
     let surfaceGeometry = new THREE.BufferGeometry();
-    surfaceGeometry.setAttribute('position', new THREE.BufferAttribute(surface.vert, 3) );
+    surfaceGeometry.setAttribute('position', new THREE.BufferAttribute(new Float32Array(surface.vertices.flat()), 3) );
     surfaceGeometry.setIndex(surface.triPointVert);
     surfaceGeometry.computeVertexNormals(true);
 
@@ -45,9 +45,12 @@ let surfaceTest = () =>
         DOM:"canvas",
         Init(inScene)
         {   
-            inScene.add(new THREE.PointLight(0xffffff, 1, 100))
+            let light = new THREE.PointLight(0xffffff, 1, 100)
+            light.position.set(0, 2, -4);
+            inScene.add(light)
             inScene.add(surfaceObject);
             inScene.add(new THREE.GridHelper(10, 10));
+            inScene.add(new THREE.AxesHelper( 5 ));
         },
         Update(inScene, inDelta){}
     };
diff --git a/region.js b/region.js
index 9a4f739..43f1812 100644
--- a/region.js
+++ b/region.js
@@ -14,55 +14,87 @@ export const Region =
     },
     Surface(inVoxels)
     {
-        function Vert(a)
+        var vertices = []; // array of surface vertices
+        var voxPointVert = []; // vox array, contains integer pointers to vertices
+        var triPointVert = []; // triangle array, contains integer pointers to vertices
+        var vertPointNeighbors = []; // vertex array, contains arrays of integer pointers to vertices
+
+        function Vert(inVoxIndex)
         {
-            var vertPointer = voxPointVert[a]
+            /*
+                If not preexisting, create a vertex with the coordinates of the voxel at `voxPointVert[inVoxIndex]`.
+                Add the new vertex to `vertices`.
+                Initialize empty neighbor connections.
+                Put the *index* of new vertex back in the voxel array at `inVoxIndex`
+                Return the vertex *index*, plus a flag if a vertex was already there.
+
+                Impure refs: voxPointVert, vertPointNeighbors, vertices
+            */
+            var vertPointer = voxPointVert[inVoxIndex]
             if(vertPointer === undefined)
             {
-                let vert = Region.XYZ(a);
+                let vert = Region.XYZ(inVoxIndex);
                 vertPointer = vertices.length;
-                voxPointVert[a] = vertPointer;
+                voxPointVert[inVoxIndex] = vertPointer;
                 vertPointNeighbors.push([]);
                 vertices.push(vert);
+
+                return [vertPointer, false];
+            }
+            else
+            {
+                return [vertPointer, true];
             }
-            return vertPointer;
         }
-        function Face(a, b, c, d)
+        function Edge(vert1, vert1WasFull, vert2, vert2WasFull)
         {
-            let p1 = Vert(a);
-            let p2 = Vert(b);
-            let p3 = Vert(c);
-            let p4 = Vert(d);
+            /*
+                Sets up neighbor relationships between vert1 and vert2.
+                Contains a check for if they have already been connected.
+
+                Impure refs: vertPointNeighbors
+            */
+
+            let p1Neighbors = vertPointNeighbors[vert1];
+            let p2Neighbors = vertPointNeighbors[vert2];
+
+            // if the two verts were already filled
+            if((vert1WasFull && vert2WasFull))
+            {
+                // it's possible that they are already connected
+                if(p1Neighbors.indexOf(vert2) !== -1)
+                {
+                    // quit if they are
+                    return;
+                }
+            }
+
+            p1Neighbors.push(vert2);
+            p2Neighbors.push(vert1);
+        }
+        function Face(a, b, c, d /* vox indices */)
+        {
+            let [p1, p1WasFull] = Vert(a);
+            let [p2, p2WasFull] = Vert(b);
+            let [p3, p3WasFull] = Vert(c);
+            let [p4, p4WasFull] = Vert(d);
 
             triPointVert.push(p1, p2, p3, p3, p4, p1);
 
-            vertPointNeighbors[p1].push(p2);
-            vertPointNeighbors[p2].push(p1);
-
-            vertPointNeighbors[p2].push(p3);
-            vertPointNeighbors[p3].push(p2);
-
-            vertPointNeighbors[p3].push(p4);
-            vertPointNeighbors[p4].push(p3);
-
-            vertPointNeighbors[p4].push(p1);
-            vertPointNeighbors[p1].push(p2);
+            Edge(p1, p1WasFull, p2, p2WasFull);
+            Edge(p2, p2WasFull, p3, p3WasFull);
+            Edge(p3, p3WasFull, p4, p4WasFull);
+            Edge(p4, p4WasFull, p1, p1WasFull);
         }
 
-        var vertices = [];
-        var voxPointVert = [];
-        var triPointVert = [];
-        var vertPointNeighbors = [];
-
         var i;
+        var x, y, z;
         var BA, BU, BC, BR,  TA, TU, TC, TR,  CL, CD, CB;
         for(i=0; i<inVoxels.length; i++)
         {
             if(inVoxels[i])
             {
-                let [x, y, z] = Region.XYZ(i);
-
-                console.log("at", x, y, z);
+                [x, y, z] = Region.XYZ(i);
 
                 // bottom: at, "up", corner, right
                 BA = i;
@@ -91,6 +123,6 @@ export const Region =
             }
         }
 
-        return {vert:new Float32Array(vertices.flat()), voxPointVert, triPointVert, vertPointNeighbors};
+        return {vertices, triPointVert, vertPointNeighbors};
     }
 };
diff --git a/scene.js b/scene.js
index c4734ba..ae36fe5 100644
--- a/scene.js
+++ b/scene.js
@@ -45,7 +45,7 @@ export function Scene(inSettings)
     scene.add(light);
     //scene.add(new T.GridHelper(10, 10));
     light.position.set(-1, 2, 4);
-    camera.position.set(0, 5, 5);
+    camera.position.set(-1, 2, -1);
     camera.lookAt(new T.Vector3(0,0,0));
     controls.update();