webgl fix

Author: munrocket

README.md

@@ -14,7 +14,7 @@ IEEE arithmetic and can produce artifacts, but CPU arithmetic is robust and brow
 ### Benchmark
 ![](https://i.imgur.com/dXeSYKO.png)
 
-You can check [quality/performance](https://munrocket.github.io/double.js/test/bench/bench.html) and [correctness](https://munrocket.github.io/double.js/test/e2e.html) of double.js library in your browser.
+You can check [quality / performance](https://munrocket.github.io/double.js/test/bench/bench.html) and [correctness](https://munrocket.github.io/double.js/test/e2e.html) of double.js library in your browser.
 
 ### Usage
 Include double.js script to webpage or install npm package. Here some basic examples

dist/double.esm.js

@@ -19,7 +19,7 @@ function oneSqr(a) {
   let hl = al * ah;
   return { hi: t, lo: ah * ah - t + hl + hl + al * al };
 }
-export class Double {
+class Double {
   constructor(obj) {
     if (obj instanceof Double) {
       this.hi = obj.hi;
@@ -515,4 +515,5 @@ export class Double {
     return Double.pow2n(Double.clone(this), exp);
   }
 }
-export default { Double };
+export default Double;
+export { Double };

dist/double.js

@@ -9,7 +9,7 @@
     "watch": "onchange 'src/*.ts' -- npm run build",
     "build": "npm run build-esm && npm run build-browser && npm run build-wasm",
     "build-esm": "esbuild ./src/double.ts --outfile=./dist/double.esm.js",
-    "build-browser": "esbuild ./src/double.ts --bundle --minify --outfile=./dist/double.js",
+    "build-browser": "esbuild ./src/double.ts --bundle --outfile=./dist/double.js",
     "build-wasm": "asc --extension=.as test/bench/bench.as wasm/double.as -b test/bench/bench.wasm -O3",
     "test": "node -r esm ./test/test.js",
     "ci": "npm run start & sleep 3 && npm run e2e && npm run cov",

package.json

@@ -30,7 +30,7 @@ function oneSqr(a: float) {
 
 /* Main class for double-word arithmetic */
 
-export class Double {
+class Double {
 
   hi: float;
   lo: float;
@@ -412,4 +412,5 @@ export class Double {
   pown(exp: float): Double { return Double.pow2n(Double.clone(this), exp); }
 }
 
-export default { Double };
+export default Double;
+export { Double };

src/double.ts

@@ -30,7 +30,10 @@ vec2 add22(vec2 X, vec2 Y) {
 }
 
 vec2 sub22(vec2 X, vec2 Y) {
-  return add22(X, -Y);
+  vec2 S = twoSum(X[0], -Y[0]);
+  vec2 T = twoSum(X[1], -Y[1]);
+  vec2 V = fastTwoSum(S[0], add(S[1], T[0]));
+  return fastTwoSum(V[0], add(T[1], V[1]));
 }
 
 vec2 mul22(vec2 X, vec2 Y) {
@@ -41,8 +44,8 @@ vec2 mul22(vec2 X, vec2 Y) {
 }
 
 vec2 div22(vec2 X, vec2 Y) {
-  float s = X[0] / Y[0];
+  float s = div(X[0], Y[0]);
   vec2 T = twoProd(s, Y[0]);
-  float e = ((((X[0] - T[0]) - T[1]) + X[1]) - s * Y[1]) / Y[0];
-  return fastTwoSum(s, e);
-}
+  float c = add(sub(sub(X[0], T[0]), T[1]), X[1]);
+  return fastTwoSum(s, div(sub(c, mul(s, Y[1])), Y[0]));
+}

webgl/double.glsl

@@ -17,6 +17,13 @@
 // Algorithm using fma for faster dd multimplication
 // More information: https://github.com/munrocket/double.js
 
+// MIT License. © 2022 munrocket
+//
+// Emulated double precision lib with mandelbrot set
+// Bottom is always pixelated, top is smooth with double
+// Algorithm using fma for faster dd multimplication
+// Additional information: https://github.com/munrocket/double.js
+
 float add(float a, float b) { return (b != 0.) ? a + b : a; }
 float sub(float a, float b) { return (b != 0.) ? a - b : a; }
 float mul(float a, float b) { return (b != 1.) ? a * b : a; }
@@ -47,7 +54,10 @@
 }
 
 vec2 sub22(vec2 X, vec2 Y) {
-  return add22(X, -Y);
+  vec2 S = twoSum(X[0], -Y[0]);
+  vec2 T = twoSum(X[1], -Y[1]);
+  vec2 V = fastTwoSum(S[0], add(S[1], T[0]));
+  return fastTwoSum(V[0], add(T[1], V[1]));
 }
 
 vec2 mul22(vec2 X, vec2 Y) {
@@ -58,14 +68,16 @@
 }
 
 vec2 div22(vec2 X, vec2 Y) {
-  float s = X[0] / Y[0];
+  float s = div(X[0], Y[0]);
   vec2 T = twoProd(s, Y[0]);
-  float e = ((((X[0] - T[0]) - T[1]) + X[1]) - s * Y[1]) / Y[0];
-  return fastTwoSum(s, e);
+  float c = add(sub(sub(X[0], T[0]), T[1]), X[1]);
+  return fastTwoSum(s, div(sub(c, mul(s, Y[1])), Y[0]));
 }
 
 //////// end of the library, begin mandelbrot example /////////
 
+//////// end of the library, begin mandelbrot example /////////
+
 vec4 dcadd(vec4 a, vec4 b){
   return vec4(add22(a.xy, b.xy), add22(a.zw, b.zw));
 }
@@ -87,38 +99,43 @@
   return vec4(mul22(c.xy, k), mul22(c.zw, k));
 }
 
-const float zoom = 7.4e5;
+#define zoom 7.4e5
 const vec4 p0 = vec4(-0.2351255, -1e-8, 0.8272157, -1e-9);
-const vec4 color = vec4(1, 2, 2.9,0);
 vec2 d(float a) { return vec2(a, 0); }
 vec4 dc(vec2 c) { return vec4(c.x, 0, c.y, 0); }
+vec4 col(float i) {
+  return .1+.9*cos(log(i*i)*vec4(1, 2, 2.9,0));
+}
 
 vec4 single_fractal(vec4 o) {
   vec2 c = iResolution.xy, z = gl_FragCoord.xy;
-  c = z = (z-.5*c)/c.y/zoom + p0.xz;
+  c = z = (z-.5*c)/(zoom)/c.y + p0.xz;
   for (float i; i < 1.; i += 1e-3) {
-    dot(z = mat2(z,-z.y,z.x)*z + c, z) > 4. ? o = cos(color*log(i*i)) : o;
+    if(dot(z = mat2(z,-z.y,z.x)*z + c, z) > 4.)
+      o = col(i);
   }
   return o;
 }
 
 vec4 double_fractal(vec4 o) {
   vec2 c0 = iResolution.xy, z0 = gl_FragCoord.xy;
-  vec4 z, c = z = dcadd(
-    fcmul(dcsub(dc(z0), dc(.5*c0)), div22(d(1.), twoProd(c0.y, zoom))), p0);
+  vec4 z, c = z = dcadd(fcmul(dcsub(dc(z0), dc(.5*c0)),
+    div22(d(1.), twoProd(c0.y, zoom))), p0);
   for (float i; i < 1.; i += 1e-3) {
-    dclen(z = dcadd(dcmul(z, z), c)).x > 4. ? o = cos(color*log(i*i)) : o;
+    if(dclen(z = dcadd(dcmul(z, z), c)).x > 4.)
+      o = col(i);
   }
   return o;
 }
 
 void mainImage( out vec4 o, in vec2 fc ) {
-  if (fc.y / iResolution.y + fc.x / iResolution.x < 1.) {
+  vec2 uv = fc / iResolution.xy;
+  if (uv.x + uv.y < 1.) {
     o = single_fractal(o);
   } else {
     o = double_fractal(o);
   }
-  o += .02;
+  o -= smoothstep(.0025, .001, abs(uv.x+uv.y-1.))
 }
     `);
   </script>

webgl/test.html

@@ -28,8 +28,11 @@ fn add22(X: vec2<f32>, Y: vec2<f32>) -> vec2<f32> {
   return fastTwoSum(V[0], add(T[1], V[1]));
 }
 
-fn sub22(X: vec2<f32>, Y: vec2<f32>) -> vec2<f32> {
-  return add22(X, -Y);
+fn add22(X: vec2<f32>, Y: vec2<f32>) -> vec2<f32> {
+  let S = twoSum(X[0], -Y[0]);
+  let T = twoSum(X[1], -Y[1]);
+  let V = fastTwoSum(S[0], add(S[1], T[0]));
+  return fastTwoSum(V[0], add(T[1], V[1]));
 }
 
 fn mul22(X: vec2<f32>, Y: vec2<f32>) -> vec2<f32> {
@@ -41,6 +44,6 @@ fn mul22(X: vec2<f32>, Y: vec2<f32>) -> vec2<f32> {
 fn div22(X: vec2<f32>, Y: vec2<f32>) -> vec2<f32> {
   let s = div(X[0], Y[0]);
   let T = twoProd(s, Y[0]);
-  let e = div(sub(add(sub(sub(X[0], T[0]), T[1]), X[1]), mul(s, Y[1])), Y[0]);
-  return fastTwoSum(s, e);
+  let c = add(sub(sub(X[0], T[0]), T[1]), X[1]);
+  return fastTwoSum(s, div(sub(c, mul(s, Y[1])), Y[0]));
 }