forked from glen/dyna3
409 lines
No EOL
16 KiB
Rust
409 lines
No EOL
16 KiB
Rust
// based on the WebGL example in the `wasm-bindgen` guide
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//
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// https://rustwasm.github.io/wasm-bindgen/examples/webgl.html
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//
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// and this StackOverflow answer by wangdq
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//
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// https://stackoverflow.com/a/39684775
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//
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extern crate js_sys;
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use sycamore::{prelude::*, rt::{JsCast, JsValue}};
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use web_sys::{console, WebGl2RenderingContext, WebGlShader};
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fn compile_shader(
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context: &WebGl2RenderingContext,
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shader_type: u32,
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source: &str,
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) -> WebGlShader {
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let shader = context.create_shader(shader_type).unwrap();
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context.shader_source(&shader, source);
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context.compile_shader(&shader);
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shader
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}
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// load the given data into the vertex input of the given name
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fn bind_vertex_attrib(
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context: &WebGl2RenderingContext,
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index: u32,
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size: i32,
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data: &[f32]
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) {
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// create a data buffer and bind it to ARRAY_BUFFER
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let buffer = context.create_buffer().unwrap();
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context.bind_buffer(WebGl2RenderingContext::ARRAY_BUFFER, Some(&buffer));
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// load the given data into the buffer. the function `Float32Array::view`
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// creates a raw view into our module's `WebAssembly.Memory` buffer.
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// allocating more memory will change the buffer, invalidating the view.
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// that means we have to make sure we don't allocate any memory until the
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// view is dropped
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unsafe {
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context.buffer_data_with_array_buffer_view(
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WebGl2RenderingContext::ARRAY_BUFFER,
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&js_sys::Float32Array::view(&data),
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WebGl2RenderingContext::STATIC_DRAW,
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);
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}
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// allow the target attribute to be used
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context.enable_vertex_attrib_array(index);
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// take whatever's bound to ARRAY_BUFFER---here, the data buffer created
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// above---and bind it to the target attribute
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//
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// https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext/vertexAttribPointer
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//
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context.vertex_attrib_pointer_with_i32(
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index,
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size,
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WebGl2RenderingContext::FLOAT,
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false, // don't normalize
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0, // zero stride
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0, // zero offset
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);
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}
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fn main() {
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// set up a config option that forwards panic messages to `console.error`
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#[cfg(feature = "console_error_panic_hook")]
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console_error_panic_hook::set_once();
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sycamore::render(|| {
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let ctrl_x = create_signal(0.0);
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let ctrl_y = create_signal(0.0);
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let radius_x = create_signal(1.0);
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let radius_y = create_signal(1.0);
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let opacity = create_signal(0.5);
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let layer_threshold = create_signal(0.0);
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let display = create_node_ref();
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on_mount(move || {
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// get the display canvas
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let canvas = display
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.get::<DomNode>()
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.unchecked_into::<web_sys::HtmlCanvasElement>();
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let ctx = canvas
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.get_context("webgl2")
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.unwrap()
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.unwrap()
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.dyn_into::<WebGl2RenderingContext>()
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.unwrap();
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// compile and attach the vertex and fragment shaders
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let vertex_shader = compile_shader(
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&ctx,
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WebGl2RenderingContext::VERTEX_SHADER,
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r##"#version 300 es
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in vec4 position;
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void main() {
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gl_Position = position;
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}
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"##,
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);
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let fragment_shader = compile_shader(
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&ctx,
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WebGl2RenderingContext::FRAGMENT_SHADER,
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r##"#version 300 es
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precision highp float;
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out vec4 outColor;
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// view
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uniform vec2 resolution;
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uniform float shortdim;
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// controls
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uniform vec2 ctrl;
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uniform vec2 radius;
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uniform float opacity;
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uniform int layer_threshold;
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// light and camera
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const float focal_slope = 0.3;
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const vec3 light_dir = normalize(vec3(2., 2., 1.));
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const float ixn_threshold = 0.005;
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// --- sRGB ---
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// map colors from RGB space to sRGB space, as specified in the
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// sRGB standard (IEC 61966-2-1:1999)
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//
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// https://www.color.org/sRGB.pdf
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// https://www.color.org/chardata/rgb/srgb.xalter
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//
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// in RGB space, color value is proportional to light intensity,
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// so linear color-vector interpolation corresponds to physical
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// light mixing. in sRGB space, the color encoding used by many
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// monitors, we use more of the value interval to represent low
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// intensities, and less of the interval to represent high
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// intensities. this improves color quantization
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float sRGB(float t) {
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if (t <= 0.0031308) {
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return 12.92*t;
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} else {
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return 1.055*pow(t, 5./12.) - 0.055;
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}
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}
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vec3 sRGB(vec3 color) {
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return vec3(sRGB(color.r), sRGB(color.g), sRGB(color.b));
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}
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// --- inversive geometry ---
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struct vecInv {
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vec3 sp;
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vec2 lt;
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};
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vecInv sphere(vec3 center, float radius) {
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return vecInv(
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center / radius,
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vec2(
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0.5 / radius,
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0.5 * (dot(center, center) / radius - radius)
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)
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);
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}
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// --- shading ---
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struct taggedFrag {
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int id;
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vec4 color;
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vec3 pt;
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vec3 normal;
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};
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taggedFrag[2] sort(taggedFrag a, taggedFrag b) {
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taggedFrag[2] result;
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if (a.pt.z > b.pt.z) {
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result[0] = a;
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result[1] = b;
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} else {
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result[0] = b;
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result[1] = a;
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}
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return result;
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}
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taggedFrag sphere_shading(vecInv v, vec3 pt, vec3 base_color, int id) {
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// the expression for normal needs to be checked. it's
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// supposed to give the negative gradient of the lorentz
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// product between the impact point vector and the sphere
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// vector with respect to the coordinates of the impact
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// point. i calculated it in my head and decided that
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// the result looked good enough for now
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vec3 normal = normalize(-v.sp + 2.*v.lt.s*pt);
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float incidence = dot(normal, light_dir);
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float illum = mix(0.4, 1.0, max(incidence, 0.0));
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return taggedFrag(id, vec4(illum * base_color, opacity), pt, normal);
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}
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// --- ray-casting ---
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vec2 sphere_cast(vecInv v, vec3 dir) {
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float a = -v.lt.s * dot(dir, dir);
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float b = dot(v.sp, dir);
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float c = -v.lt.t;
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float scale = -b/(2.*a);
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float adjust = 4.*a*c/(b*b);
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if (adjust < 1.) {
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float offset = sqrt(1. - adjust);
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return vec2(
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scale * (1. - offset),
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scale * (1. + offset)
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);
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} else {
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// these parameters describe points behind the camera,
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// so the corresponding fragments won't be drawn
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return vec2(-1., -1.);
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}
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}
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void main() {
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vec2 scr = (2.*gl_FragCoord.xy - resolution) / shortdim;
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vec3 dir = vec3(focal_slope * scr, -1.);
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// initialize two spheres
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vecInv v [2];
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v[0] = sphere(vec3(0.5, 0.5, -5. + ctrl.x), radius.x);
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v[1] = sphere(vec3(-0.5, -0.5, -5. + ctrl.y), radius.y);
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vec3 color0 = vec3(1., 0.214, 0.);
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vec3 color1 = vec3(0., 0.214, 1.);
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// cast rays through the spheres
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vec2 u0 = sphere_cast(v[0], dir);
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vec2 u1 = sphere_cast(v[1], dir);
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// shade and depth-sort the impact points
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taggedFrag front_hits[2] = sort(
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sphere_shading(v[0], u0[0] * dir, color0, 0),
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sphere_shading(v[1], u1[0] * dir, color1, 1)
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);
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taggedFrag back_hits[2] = sort(
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sphere_shading(v[0], u0[1] * dir, color0, 0),
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sphere_shading(v[1], u1[1] * dir, color1, 1)
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);
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taggedFrag middle_frags[2] = sort(front_hits[1], back_hits[0]);
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// finish depth sorting
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taggedFrag frags_by_depth[4];
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frags_by_depth[0] = front_hits[0];
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frags_by_depth[1] = middle_frags[0];
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frags_by_depth[2] = middle_frags[1];
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frags_by_depth[3] = back_hits[1];
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// highlight intersections and cusps
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for (int i = 3; i >= 1; --i) {
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// intersections
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taggedFrag frag0 = frags_by_depth[i];
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taggedFrag frag1 = frags_by_depth[i-1];
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float ixn_sin = length(cross(frag0.normal, frag1.normal));
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vec3 disp = frag0.pt - frag1.pt;
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float ixn_dist = max(
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abs(dot(frag1.normal, disp)),
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abs(dot(frag0.normal, disp))
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) / ixn_sin;
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float ixn_highlight = 1. - smoothstep(2./3.*ixn_threshold, 1.5*ixn_threshold, ixn_dist);
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frags_by_depth[i].color = mix(frags_by_depth[i].color, vec4(1.), ixn_highlight);
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frags_by_depth[i-1].color = mix(frags_by_depth[i-1].color, vec4(1.), ixn_highlight);
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// cusps
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float cusp_cos = abs(dot(dir, frag0.normal));
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float cusp_threshold = 2.*sqrt(ixn_threshold * v[frag0.id].lt.s);
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float cusp_highlight = 1. - smoothstep(2./3.*cusp_threshold, 1.5*cusp_threshold, cusp_cos);
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frags_by_depth[i].color = mix(frags_by_depth[i].color, vec4(1.), cusp_highlight);
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}
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// composite the sphere fragments
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vec3 color = vec3(0.);
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for (int i = 3; i >= layer_threshold; --i) {
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if (frags_by_depth[i].pt.z < 0.) {
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vec4 frag_color = frags_by_depth[i].color;
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color = mix(color, frag_color.rgb, frag_color.a);
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}
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}
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outColor = vec4(sRGB(color), 1.);
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}
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"##,
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);
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let program = ctx.create_program().unwrap();
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ctx.attach_shader(&program, &vertex_shader);
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ctx.attach_shader(&program, &fragment_shader);
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ctx.link_program(&program);
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let link_status = ctx
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.get_program_parameter(&program, WebGl2RenderingContext::LINK_STATUS)
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.as_bool()
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.unwrap();
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let link_msg = if link_status {
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"Linked successfully"
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} else {
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"Linking failed"
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};
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console::log_1(&JsValue::from(link_msg));
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ctx.use_program(Some(&program));
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// find indices of vertex attributes and uniforms
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let position_index = ctx.get_attrib_location(&program, "position") as u32;
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let resolution_loc = ctx.get_uniform_location(&program, "resolution");
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let shortdim_loc = ctx.get_uniform_location(&program, "shortdim");
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let ctrl_loc = ctx.get_uniform_location(&program, "ctrl");
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let radius_loc = ctx.get_uniform_location(&program, "radius");
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let opacity_loc = ctx.get_uniform_location(&program, "opacity");
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let layer_threshold_loc = ctx.get_uniform_location(&program, "layer_threshold");
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// create a vertex array and bind it to the graphics context
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let vertex_array = ctx.create_vertex_array().unwrap();
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ctx.bind_vertex_array(Some(&vertex_array));
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// set the vertex positions
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const VERTEX_CNT: usize = 6;
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let positions: [f32; 3*VERTEX_CNT] = [
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// northwest triangle
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-1.0, -1.0, 0.0,
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-1.0, 1.0, 0.0,
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1.0, 1.0, 0.0,
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// southeast triangle
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-1.0, -1.0, 0.0,
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1.0, 1.0, 0.0,
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1.0, -1.0, 0.0
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];
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bind_vertex_attrib(&ctx, position_index, 3, &positions);
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// set up a repainting routine
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create_effect(move || {
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// set the resolution
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let width = canvas.width() as f32;
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let height = canvas.height() as f32;
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ctx.uniform2f(resolution_loc.as_ref(), width, height);
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ctx.uniform1f(shortdim_loc.as_ref(), width.min(height));
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// pass the control parameters
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ctx.uniform2f(ctrl_loc.as_ref(), ctrl_x.get() as f32, ctrl_y.get() as f32);
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ctx.uniform2f(radius_loc.as_ref(), radius_x.get() as f32, radius_y.get() as f32);
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ctx.uniform1f(opacity_loc.as_ref(), opacity.get() as f32);
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ctx.uniform1i(layer_threshold_loc.as_ref(), layer_threshold.get() as i32);
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// clear the screen and draw the scene
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ctx.clear_color(0.0, 0.0, 0.0, 1.0);
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ctx.clear(WebGl2RenderingContext::COLOR_BUFFER_BIT);
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ctx.draw_arrays(WebGl2RenderingContext::TRIANGLES, 0, VERTEX_CNT as i32);
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});
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});
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view! {
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div(id="app") {
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canvas(ref=display, width="600", height="600")
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input(
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type="range",
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min=-1.0,
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max=1.0,
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step=0.001,
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bind:valueAsNumber=ctrl_x
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)
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input(
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type="range",
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min=-1.0,
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max=1.0,
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step=0.001,
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bind:valueAsNumber=ctrl_y
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)
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input(
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type="range",
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min=0.5,
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max=1.5,
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step=0.001,
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bind:valueAsNumber=radius_x
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)
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input(
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type="range",
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min=0.5,
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max=1.5,
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step=0.001,
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bind:valueAsNumber=radius_y
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)
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input(
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type="range",
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max=1.0,
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step=0.001,
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bind:valueAsNumber=opacity
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)
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input(
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type="range",
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max=3.0,
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step=1.0,
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bind:valueAsNumber=layer_threshold
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)
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}
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}
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});
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} |