Merge pull request #8800 from harshiltewari2004/strands-random-gaussian

Add p5.strands support for randomGaussian()

Author: perminder-17

src/strands/strands_api.js

@@ -337,6 +337,7 @@ export function initGlobalStrandsAPI(p5, fn, strandsContext) {
   const originalNoise = fn.noise;
   const originalNoiseDetail = fn.noiseDetail;
   const originalRandom = fn.random;
+  const originalRandomGaussian=fn.randomGaussian;
   const originalRandomSeed = fn.randomSeed;
   const originalMillis = fn.millis;
 
@@ -480,6 +481,20 @@ export function initGlobalStrandsAPI(p5, fn, strandsContext) {
     }
   });
 
+   augmentFn(fn, p5, 'randomGaussian', function(...args){
+      if(!strandsContext.active){
+        return originalRandomGaussian.apply(this, args);
+      }
+      const mean = args.length >= 1 ? args[0] : 0;
+      const stdDev = args.length >= 2 ? args[1] : 1;
+
+      const u1 = this.max(this.random(), 1e-6);
+      const u2 = this.random();
+      const z = this.sqrt(this.log(u1).mult(-2)).mult(this.cos(u2.mult(2*Math.PI)));
+
+      return z.mult(stdDev).add(mean);
+    });
+
   augmentFn(fn, p5, 'millis', function (...args) {
     if (!strandsContext.active) {
       return originalMillis.apply(this, args);

test/unit/visual/cases/webgl.js

@@ -1133,6 +1133,44 @@ visualSuite('WebGL', function() {
       screenshot();
     });
 
+    visualTest('randomGaussian() colors a basic shader', (p5, screenshot) => {
+  p5.createCanvas(50, 50, p5.WEBGL);
+  const shader = p5.baseColorShader().modify(() => {
+    p5.randomSeed(12);
+    p5.getFinalColor((color) => {
+      const value = p5.randomGaussian(0.5, 0.1);
+      color = [value, value, value, 1];
+      return color;
+    });
+  }, { p5 });
+  p5.background(0);
+  p5.noStroke();
+  p5.shader(shader);
+  p5.plane(50, 50);
+  screenshot();
+});
+
+visualTest('randomGaussian() in a fragment loop averages to the mean', (p5, screenshot) => {
+  p5.createCanvas(50, 50, p5.WEBGL);
+  const shader = p5.baseMaterialShader().modify(() => {
+    p5.randomSeed(7);
+    p5.getPixelInputs(inputs => {
+      let sum = p5.float(0.0);
+      for (let i = 0; i < 20; i++) {
+        sum = sum + p5.randomGaussian(0.5, 0.2);
+      }
+      const avg = sum / 20;
+      inputs.color = [avg, avg, avg, 1.0];
+      return inputs;
+    });
+  }, { p5 });
+  p5.background(0);
+  p5.noStroke();
+  p5.shader(shader);
+  p5.plane(50, 50);
+  screenshot();
+});
+
     visualTest('uses width/height in getFinalColor', (p5, screenshot) => {
       let firstShader;
       function firstShaderCallback() {

test/unit/visual/cases/webgpu.js

@@ -366,6 +366,44 @@ visualSuite("WebGPU", function () {
     });
   });
 
+  visualTest('randomGaussian() colors a basic shader (WebGPU)', async function(p5, screenshot) {
+  await p5.createCanvas(50, 50, p5.WEBGPU);
+  const shader = p5.baseColorShader().modify(() => {
+    p5.randomSeed(12);
+    p5.getFinalColor((color) => {
+      const value = p5.randomGaussian(0.5, 0.1);
+      color = [value, value, value, 1];
+      return color;
+    });
+  }, { p5 });
+  p5.background(0);
+  p5.noStroke();
+  p5.shader(shader);
+  p5.plane(50, 50);
+  await screenshot();
+});
+
+visualTest('randomGaussian() in a fragment loop averages to the mean (WebGPU)', async function(p5, screenshot) {
+  await p5.createCanvas(50, 50, p5.WEBGPU);
+  const shader = p5.baseMaterialShader().modify(() => {
+    p5.randomSeed(7);
+    p5.getPixelInputs(inputs => {
+      let sum = p5.float(0.0);
+      for (let i = 0; i < 20; i++) {
+        sum = sum + p5.randomGaussian(0.5, 0.2);
+      }
+      const avg = sum / 20;
+      inputs.color = [avg, avg, avg, 1.0];
+      return inputs;
+    });
+  }, { p5 });
+  p5.background(0);
+  p5.noStroke();
+  p5.shader(shader);
+  p5.plane(50, 50);
+  await screenshot();
+});
+
 
   visualSuite('filters', function() {
     const setupSketch = async (p5) => {

test/unit/visual/screenshots/WebGL/p5.strands/randomGaussian() colors a basic shader/000.png

@@ -0,0 +1,3 @@
+{
+  "numScreenshots": 1
+}

test/unit/visual/screenshots/WebGL/p5.strands/randomGaussian() colors a basic shader/metadata.json

@@ -0,0 +1,3 @@
+{
+  "numScreenshots": 1
+}

test/unit/visual/screenshots/WebGL/p5.strands/randomGaussian() in a fragment loop averages to the mean/000.png

@@ -0,0 +1,3 @@
+{
+  "numScreenshots": 1
+}