From 8ebb104bb3f6a365db416f66b872bb7ef8c368ca Mon Sep 17 00:00:00 2001
From: Mike Lynch <m.lynch@sydney.edu.au>
Date: Thu, 25 Apr 2024 10:37:45 +1000
Subject: [PATCH] Isometric projections

---
 fourDShape.js | 39 ++++++++++++++++++++-------------------
 1 file changed, 20 insertions(+), 19 deletions(-)

diff --git a/fourDShape.js b/fourDShape.js
index d42ac17..e5d125e 100644
--- a/fourDShape.js
+++ b/fourDShape.js
@@ -20,6 +20,7 @@ class FourDShape extends THREE.Group {
 		this.node_scale = 1;
 		this.link_scale = 1;
 		this.hyperplane = HYPERPLANE;
+		this.projection = 1;
 		this.initShapes();
 	}
 
@@ -100,15 +101,6 @@ class FourDShape extends THREE.Group {
 	}
 
 
-	fourDtoV3_old(x, y, z, w, rotations) {
-		const v4 = new THREE.Vector4(x, y, z, w);
-		for ( const m4 of rotations ) {
-			v4.applyMatrix4(m4);
-		}
-		const k = this.fourDscale(v4.w);
-		return new THREE.Vector3(v4.x * k, v4.y * k, v4.z * k);
-	}
-
 	fourDscale(w) {
 		return this.hyperplane / ( this.hyperplane + w );
 	}
@@ -121,11 +113,24 @@ class FourDShape extends THREE.Group {
 		return v4;
 	}
 
-	fourDtoV3(v4) {
+	renderNodePerspective(n, rotations) {
+		const v4 = this.fourDrotate(n.x, n.y, n.z, n.w, rotations);
 		const k = this.fourDscale(v4.w);
-		return new THREE.Vector3(v4.x * k, v4.y * k, v4.z * k);		
+		const position = new THREE.Vector3(v4.x * k, v4.y * k, v4.z * k);
+		const s4 = k * this.node_scale * NODE_FORESHORTENING;
+		const scale = new THREE.Vector3(s4, s4, s4);
+		return { position: position, scale: scale }
 	}
 
+	renderNodeIsometric(n, rotations) {
+		const v4 = this.fourDrotate(n.x, n.y, n.z, n.w, rotations);
+		const position = new THREE.Vector3(v4.x, v4.y + v4.w, v4.z);
+		const s4 = this.node_scale;
+		const scale = new THREE.Vector3(s4, s4, s4);
+		return { position: position, scale: scale }
+	}
+
+
 	initShapes() {
 		for( const n of this.nodes4 ) {
 			const k = this.fourDscale(n.w);
@@ -151,14 +156,10 @@ class FourDShape extends THREE.Group {
 	render3(rotations, nodes_show, links_show) {
 		this.scalev3 = new THREE.Vector3(this.node_scale, this.node_scale, this.node_scale);
 		for( const n of this.nodes4 ) {
-			const v4 = this.fourDrotate(n.x, n.y, n.z, n.w,  rotations);
-			const k = this.fourDscale(v4.w);
-			const v3 = new THREE.Vector3(v4.x * k, v4.y * k, v4.z * k);
-			const s4 = k * this.node_scale * NODE_FORESHORTENING;
-			const s3 = new THREE.Vector3(s4, s4, s4);
-			this.nodes3[n.id].v3 = v3;
-			this.nodes3[n.id].object.position.copy(v3);
-			this.nodes3[n.id].object.scale.copy(s3);
+			const node3d = this.renderNodeIsometric(n, rotations);
+			this.nodes3[n.id].v3 = node3d.position;
+			this.nodes3[n.id].object.position.copy(node3d.position);
+			this.nodes3[n.id].object.scale.copy(node3d.scale);
 			this.nodes3[n.id].object.visible = ( !nodes_show || n.label in nodes_show );
 		}
 		for( const l of this.links ) {