From f9d8886fbac489cf4dbaf5a6cfa916c7242e5e31 Mon Sep 17 00:00:00 2001
From: Magnus Ulimoen <flymagnus@gmail.com>
Date: Fri, 9 Aug 2019 21:34:39 +0200
Subject: [PATCH] improve plotting of fields

---
 main.js    | 14 ++++++++++----
 src/lib.rs | 20 +++++---------------
 2 files changed, 15 insertions(+), 19 deletions(-)

diff --git a/main.js b/main.js
index c26ad68..f0b416b 100644
--- a/main.js
+++ b/main.js
@@ -43,10 +43,10 @@ async function run() {
             mediump float b = 0.0;
             if (uChosenField == 1) {
                 r = texture2D(uSamplerEX, vVertexPosition).a;
-                r = (r + 1.0)/2.0;
+                r += 0.5;
             } else if (uChosenField == 3) {
                 b = texture2D(uSamplerEY, vVertexPosition).a;
-                b = (b + 1.0)/2.0;
+                b += 0.5;
             } else if (uChosenField == 2) {
                 g = texture2D(uSamplerHZ, vVertexPosition).a;
                 g = (g + 1.0)/2.0;
@@ -122,7 +122,7 @@ async function run() {
 
     const chosen_field = {
         uLocation: gl.getUniformLocation(shaderProgram, 'uChosenField'),
-        value: 3,
+        value: 1,
         cycle: function() {
             if (this.value == 1) {
                 this.value = 2;
@@ -153,7 +153,7 @@ async function run() {
 
     const TIMEFACTOR = 1.0/7000;
     let t = performance.now()*TIMEFACTOR;
-    universes[0].set_initial(t, "exp");
+    universes[0].set_initial(0.5, 0.5);
 
     function drawMe(t_draw) {
         gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
@@ -215,6 +215,12 @@ async function run() {
             chosen_field.cycle();
         }
     }, {passive: true});
+    window.addEventListener('click', event => {
+        const mousex = event.clientX / window.innerWidth;
+        const mousey = event.clientY / window.innerHeight;
+        universes[0].set_initial(mousex, 1.0 - mousey);
+    }, {passive: true});
+
     resizeCanvas();
     window.requestAnimationFrame(drawMe);
 }
diff --git a/src/lib.rs b/src/lib.rs
index 2b4929f..8e8a816 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -21,15 +21,10 @@ pub fn set_panic_hook() {
     console_error_panic_hook::set_once();
 }
 
-fn sin_plus_cos(x: f32, y: f32, t: f32) -> f32 {
+fn gaussian(x: f32, x0: f32, y: f32, y0: f32) -> f32 {
     use std::f32;
-    (2.0 * f32::consts::PI * (x + y) - t).sin()
-}
-
-fn exponential(x: f32, y: f32, _t: f32) -> f32 {
-    use std::f32;
-    let x = x - 0.5;
-    let y = y - 0.5;
+    let x = x - x0;
+    let y = y - y0;
 
     let sigma = 0.05;
 
@@ -47,12 +42,7 @@ impl Universe {
         Universe { ex, ey, hz }
     }
 
-    pub fn set_initial(&mut self, t: f32, selected_function: &str) {
-        let func = match selected_function {
-            "sin+cos" => sin_plus_cos,
-            "exp" => exponential,
-            _ => |_x: f32, _y: f32, _t: f32| 0.0,
-        };
+    pub fn set_initial(&mut self, x0: f32, y0: f32) {
         let nx = self.ex.shape()[1];
         let ny = self.ex.shape()[0];
         for j in 0..ny {
@@ -63,7 +53,7 @@ impl Universe {
                 let y = j as f32 / ny as f32;
                 self.ex[(j, i)] = 0.0;
                 self.ey[(j, i)] = 0.0;
-                self.hz[(j, i)] = func(x, y, t);
+                self.hz[(j, i)] = gaussian(x, x0, y, y0) / 32.0;
             }
         }
     }