Add low-curvature construction

Also add infrastructure for switching between constructions.

app-proto/inversive-display/main.css

@@ -18,14 +18,41 @@ canvas {
   margin-top: 5px;
 }
 
-.control {
+.hidden {
+  display: none;
+}
+
+.control, .tab-pane {
   display: flex;
   flex-direction: row;
   width: 600px;
 }
 
+input[type="radio"] {
+  display: none;
+}
+
+.tab-pane > label {
+  border: 1px solid #aaa;
+  border-radius: 5px;
+  text-align: center;
+  padding: 5px;
+  margin-right: 10px;
+  margin-bottom: 5px;
+}
+
+.tab-pane > label:has(:checked) {
+  border-color: #fcfcfc;
+  background-color: #555;
+}
+
+.tab-pane > label:hover:not(:has(:checked)) {
+  border-color: #bbb;
+  background-color: #333;
+}
+
 label {
-  width: 150px;
+  width: 170px;
 }
 
 input {

app-proto/inversive-display/src/inversive.frag

@@ -46,6 +46,7 @@ uniform bool debug_mode;
 const float focal_slope = 0.3;
 const vec3 light_dir = normalize(vec3(2., 2., 1.));
 const float ixn_threshold = 0.005;
+const float INTERIOR_DIMMING = 0.7;
 
 // --- sRGB ---
 
@@ -143,6 +144,7 @@ void main() {
         vec2 hit_depths = sphere_cast(sphere_list[id], dir);
         
         // insertion-sort the fragments we hit into the fragment list
+        float dimming = 1.;
         for (int side = 0; side < 2; ++side) {
             float hit_z = -hit_depths[side];
             if (0. > hit_z) {
@@ -154,7 +156,7 @@ void main() {
                             frags[layer] = sphere_shading(
                                 sphere_list[id],
                                 hit_depths[side] * dir,
-                                color_list[id],
+                                dimming * color_list[id],
                                 id
                             );
                         }
@@ -167,6 +169,7 @@ void main() {
                     }
                 }
                 layer_cnt = min(layer_cnt + 1, LAYER_MAX);
+                dimming = INTERIOR_DIMMING;
             }
         }
     }

app-proto/inversive-display/src/main.rs

@@ -10,6 +10,7 @@
 extern crate js_sys;
 use core::array;
 use nalgebra::{DMatrix, DVector};
+use std::f64::consts::FRAC_1_SQRT_2;
 use sycamore::{prelude::*, motion::create_raf, rt::{JsCast, JsValue}};
 use web_sys::{console, window, WebGl2RenderingContext, WebGlProgram, WebGlShader, WebGlUniformLocation};
 
@@ -83,17 +84,62 @@ fn bind_vertex_attrib(
     );
 }
 
+fn push_gen_construction(
+    sphere_vec: &mut Vec<DVector<f64>>,
+    construction_to_world: &DMatrix<f64>,
+    ctrl_x: f64,
+    ctrl_y: f64,
+    radius_x: f64,
+    radius_y: f64
+) {
+    sphere_vec.push(construction_to_world * engine::sphere(0.5, 0.5, ctrl_x, radius_x));
+    sphere_vec.push(construction_to_world * engine::sphere(-0.5, -0.5, ctrl_y, radius_y));
+    sphere_vec.push(construction_to_world * engine::sphere(-0.5, 0.5, 0.0, 0.75));
+    sphere_vec.push(construction_to_world * engine::sphere(0.5, -0.5, 0.0, 0.5));
+    sphere_vec.push(construction_to_world * engine::sphere(0.0, 0.15, 1.0, 0.25));
+    sphere_vec.push(construction_to_world * engine::sphere(0.0, -0.15, -1.0, 0.25));
+}
+
+fn push_low_curv_construction(
+    sphere_vec: &mut Vec<DVector<f64>>,
+    construction_to_world: &DMatrix<f64>,
+    curv_x: f64,
+    curv_y: f64
+) {
+    sphere_vec.push(construction_to_world * DVector::from_column_slice(&[0.0, -1.0, 0.0, 0.5*curv_x, 0.0]));
+    sphere_vec.push(construction_to_world * DVector::from_column_slice(&[-FRAC_1_SQRT_2, 0.0, -FRAC_1_SQRT_2, 0.5*curv_y, 0.0]));
+    sphere_vec.push(construction_to_world * engine::sphere(0.5, 0.0, 0.5, FRAC_1_SQRT_2));
+    sphere_vec.push(construction_to_world * engine::sphere(-0.5, 0.0, -0.5, FRAC_1_SQRT_2));
+}
+
+#[derive(Clone, Copy, PartialEq)]
+enum Tab {
+    GenTab,
+    LowCurvTab
+}
+
 fn main() {
     // set up a config option that forwards panic messages to `console.error`
     #[cfg(feature = "console_error_panic_hook")]
     console_error_panic_hook::set_once();
     
     sycamore::render(|| {
-        // controls
+        // tab selection
+        let tab_selection = create_signal(Tab::GenTab);
+        
+        // controls for general example
+        let gen_controls = create_node_ref();
         let ctrl_x = create_signal(0.0);
         let ctrl_y = create_signal(0.0);
         let radius_x = create_signal(1.0);
         let radius_y = create_signal(1.0);
+        
+        // controls for low-curvature example
+        let low_curv_controls = create_node_ref();
+        let curv_x = create_signal(0.0);
+        let curv_y = create_signal(0.0);
+        
+        // shared controls
         let opacity = create_signal(0.5);
         let highlight = create_signal(0.2);
         let turntable = create_signal(false);
@@ -112,10 +158,20 @@ fn main() {
         // change listener
         let scene_changed = create_signal(true);
         create_effect(move || {
+            // track tab selection
+            tab_selection.track();
+            
+            // track controls for general example
             ctrl_x.track();
             ctrl_y.track();
             radius_x.track();
             radius_y.track();
+            
+            // track controls for low-curvature example
+            curv_x.track();
+            curv_y.track();
+            
+            // track shared controls
             opacity.track();
             highlight.track();
             turntable.track();
@@ -126,6 +182,23 @@ fn main() {
         });
         
         on_mount(move || {
+            // tab listener
+            create_effect(move || {
+                // get the control panel nodes
+                let gen_controls_node = gen_controls.get::<DomNode>();
+                let low_curv_controls_node = low_curv_controls.get::<DomNode>();
+                
+                // hide all the control panels
+                gen_controls_node.add_class("hidden");
+                low_curv_controls_node.add_class("hidden");
+                
+                // show the selected control panel
+                match tab_selection.get() {
+                    Tab::GenTab => gen_controls_node.remove_class("hidden"),
+                    Tab::LowCurvTab => low_curv_controls_node.remove_class("hidden")
+                }
+            });
+            
             // list construction elements
             const SPHERE_MAX: usize = 200;
             let mut sphere_vec = Vec::<DVector<f64>>::new();
@@ -292,12 +365,19 @@ fn main() {
                     
                     // update the construction
                     sphere_vec.clear();
-                    sphere_vec.push(&construction_to_world * engine::sphere(0.5, 0.5, ctrl_x.get(), radius_x.get()));
-                    sphere_vec.push(&construction_to_world * engine::sphere(-0.5, -0.5, ctrl_y.get(), radius_y.get()));
-                    sphere_vec.push(&construction_to_world * engine::sphere(-0.5, 0.5, 0.0, 0.75));
-                    sphere_vec.push(&construction_to_world * engine::sphere(0.5, -0.5, 0.0, 0.5));
-                    sphere_vec.push(&construction_to_world * engine::sphere(0.0, 0.15, 1.0, 0.25));
-                    sphere_vec.push(&construction_to_world * engine::sphere(0.0, -0.15, -1.0, 0.25));
+                    match tab_selection.get() {
+                        Tab::GenTab => push_gen_construction(
+                            &mut sphere_vec,
+                            &construction_to_world,
+                            ctrl_x.get(), ctrl_y.get(),
+                            radius_x.get(), radius_y.get()
+                        ),
+                        Tab::LowCurvTab => push_low_curv_construction(
+                            &mut sphere_vec,
+                            &construction_to_world,
+                            curv_x.get(), curv_y.get()
+                        )
+                    };
                     
                     // set the resolution
                     let width = canvas.width() as f32;
@@ -346,8 +426,29 @@ fn main() {
         
         view! {
             div(id="app") {
+                div(class="tab-pane") {
+                    label {
+                        "General"
+                        input(
+                            type="radio",
+                            name="tab",
+                            prop:checked=tab_selection.get() == Tab::GenTab,
+                            on:click=move |_| tab_selection.set(Tab::GenTab)
+                        )
+                    }
+                    label {
+                        "Low curvature"
+                        input(
+                            type="radio",
+                            name="tab",
+                            prop:checked=tab_selection.get() == Tab::LowCurvTab,
+                            on:change=move |_| tab_selection.set(Tab::LowCurvTab)
+                        )
+                    }
+                }
                 div { "Mean frame interval: " (mean_frame_interval.get()) " ms" }
                 canvas(ref=display, width="600", height="600")
+                div(ref=gen_controls) {
                     div(class="control") {
                         label(for="ctrl-x") { "Sphere 0 depth" }
                         input(
@@ -392,6 +493,31 @@ fn main() {
                             bind:valueAsNumber=radius_y
                         )
                     }
+                }
+                div(ref=low_curv_controls) {
+                    div(class="control") {
+                        label(for="curv-x") { "Sphere 0 curvature" }
+                        input(
+                            type="range",
+                            id="curv-x",
+                            min=0.0,
+                            max=2.0,
+                            step=0.001,
+                            bind:valueAsNumber=curv_x
+                        )
+                    }
+                    div(class="control") {
+                        label(for="curv-y") { "Sphere 1 curvature" }
+                        input(
+                            type="range",
+                            id="curv-y",
+                            min=0.0,
+                            max=2.0,
+                            step=0.001,
+                            bind:valueAsNumber=curv_y
+                        )
+                    }
+                }
                 div(class="control") {
                     label(for="opacity") { "Opacity" }
                     input(