Some tweaks

BivariateFunction/BivariateFunction.js

@@ -1,4 +1,17 @@
 // PointLightedCube_perFragment.js (c) 2012 matsuda, 2022 Jonathon Doran
+// BivariateFunction.js (c) 2022 John Breaux
+
+// k: number of subdivisions per edge
+// On my machine, k = [1, 256)
+// I prefer 96
+var k = 64
+// f(x, y): function to graph
+function f(x, y) {
+  var u = 80 * x - 40, v = 90 * y - 45;
+  var norm = Math.sqrt(u * u + v * v);
+  return (1 / 2) * Math.pow(Math.E, -0.04 * norm) * Math.cos(0.15 * norm)
+}
+
 
 const vertex_shader = `
   attribute vec4 a_Position;
@@ -51,13 +64,6 @@ const fragment_shader = `
     gl_FragColor = vec4(diffuse + ambient, v_Color.a);
   }	`;
 
-var scale = 192
-function f(x, y) {
-  var u = 80 * x - 40, v = 90 * y - 45;
-  var norm = Math.sqrt(u * u + v * v);
-  return (1 / 2) * Math.pow(Math.E, -0.04 * norm) * Math.cos(0.15 * norm)
-}
-
 function main() {
   // Retrieve <canvas> element
   var canvas = document.getElementById('webgl');
@@ -113,16 +119,17 @@ function main() {
   var normalMatrix = new Matrix4(); // Transformation matrix for normals
 
   // Calculate the model matrix
-  modelMatrix.setRotate(-90, 1, 0, 0); // Rotate around the *X* axis
+  // Move center of model to center
+  modelMatrix.setTranslate(-0.5, 0, 0.5)
+  // Rotate the model upright, around X
+  modelMatrix.rotate(-90, 1, 0, 0);
 
   // Calculate the view projection matrix
   mvpMatrix.setPerspective(30, canvas.width / canvas.height, 1, 100);
-  mvpMatrix.translate(0, 0, -2)
   var theta = Math.PI / 3
-  mvpMatrix.lookAt(
+  mvpMatrix.lookAt(Math.tan(theta), Math.sin(theta), Math.cos(theta), // Why fiddle with multiple constants when you can just fiddle with one?
-    Math.tan(theta) / 4, Math.sin(theta) / 4, Math.cos(theta) / 4,
+    0.0, 0.0, 0.0,
-    0, 0, 0,
+    0.0, 1.0, 0.0
-    0, 1, 0
   );
   mvpMatrix.multiply(modelMatrix);
 
@@ -147,49 +154,50 @@ function main() {
 }
 
 
-//!!! RIGHT HERE
-
 class BivariateFunction {
   vertices = [];
   vertex_colors = [];
   vertex_normals = [];
   indices = [];
 
+  resolution = 50
   func = (x, y) => { return 0; }
 
-  constructor({ width = 50, height = 50, func = this.func } = {}) {
+  constructor({ resolution = 50, func } = { resolution: 50, func: this.func }) {
-    this.width = width;
+    this.resolution = resolution;
-    this.height = height;
     this.func = func;
+    this.construct_mesh();
   }
 
-  generate_quad(width, _height, index) {
+  generate_quad(width, index) {
     var upper = [index + 1, index, index + width + 1]
     var lower = [index + 1, index + width + 1, index + width + 2]
     return [upper, lower]
   }
 
-  generate_plane() {
+  construct_mesh() {
-    var width = this.width, height = this.height;
+    var vertices = [], vertex_colors = [], vertex_normals = [], triangles = [];
-    var vertices = [], vertex_colors = [], vertex_normals = [];
+    // Generate a
-    var triangles = [];
+    for (var i = 0, y = 0; y <= this.resolution; y++) {
-    for (var i = 0, y = 0; y <= width; y++) {
+      for (var x = 0; x <= this.resolution; x++) {
-      for (var x = 0; x <= height; x++) {
         // Create a new vertex
-        vertices.push([x / width - 0.5, y / height - 0.5, this.func(x / width, y / width)]);
+        vertices.push([x / this.resolution, y / this.resolution,
+        this.func(x / this.resolution, y / this.resolution)]);
+        // Color this vertex a very pleasing shade of velvet-red
         vertex_colors.push([0.625, 0.025, 0.075])
         //vertex_colors.push([x / width, y / width, 1]);
+        // Give it a normal vector
         vertex_normals.push([0, 0, 0]);
 
         // If this point is the top-left corner of a quad,
         // then create a new quad
-        if (x < width && y < height) {
+        if (x < this.resolution && y < this.resolution) {
-          triangles.push(...this.generate_quad(width, height, i));
+          triangles.push(...this.generate_quad(this.resolution, i));
         }
         i++
       }
     }
-
+    // Sum the normals around each vertex
     for (var triangle of triangles) {
       // Turn verts into vec3's
       var v = [new vec3(...vertices[triangle[0]]), new vec3(...vertices[triangle[1]]), new vec3(...vertices[triangle[2]])];
@@ -209,11 +217,11 @@ class BivariateFunction {
       // taking full advantage of the garbage collector here
       vertex_normals[i] = new vec3(...vertex_normals[i]).normalize().a();
     }
-    // Save the vertices and indices
+    // Save the vertices and indices as flat arrays
-    this.vertices = vertices;
+    this.vertices = vertices.flat();
-    this.vertex_colors = vertex_colors;
+    this.vertex_colors = vertex_colors.flat();
-    this.vertex_normals = vertex_normals;
+    this.vertex_normals = vertex_normals.flat();
-    this.indices = triangles;
+    this.indices = triangles.flat();
     return
   }
 }
@@ -222,15 +230,13 @@ class BivariateFunction {
 function initVertexBuffers(gl) {
   // Create a new BivariateFunction
   var bf = new BivariateFunction({
-    width: scale, height: scale, func: f
+    resolution: k, func: f
   });
 
-  bf.generate_plane();
+  var vertices = new Float32Array(bf.vertices);
-
+  var colors = new Float32Array(bf.vertex_colors);
-  var vertices = new Float32Array(bf.vertices.flat());
+  var normals = new Float32Array(bf.vertex_normals);
-  var colors = new Float32Array(bf.vertex_colors.flat());
+  var indices = new Uint16Array(bf.indices);
-  var normals = new Float32Array(bf.vertex_normals.flat());
-  var indices = new Uint16Array(bf.indices.flat());
 
   // Write the vertex property to buffers (coordinates, colors and normals)
   if (!initArrayBuffer(gl, 'a_Position', vertices, 3)) return -1;

BivariateFunction/vec3.js

@@ -1,6 +1,6 @@
 // BetterVector3.js
 // John Breaux  2022-07-28
-// 3D Vector library
+// Craptastic 3D Vector library
 
 "use strict";