diff --git a/preview/index.html b/preview/index.html
index ac5bedefcc..d87cbcaf86 100644
--- a/preview/index.html
+++ b/preview/index.html
@@ -20,25 +20,28 @@
     import p5 from '../src/app.js';
 
     const sketch = function (p) {
-      let g, f;
+      let g, f,s,fragSrc;
 
       p.setup = function () {
         p.createCanvas(200, 200);
         g = p.createGraphics(200, 200);
         f = p.createGraphics(200, 200, p.WEBGL);
-      };
-
-      p.draw = function () {
-        p.background(0, 50, 50);
-        p.circle(100, 100, 50);
-
-        p.fill('white');
-        p.textSize(30);
-        p.text('hello', 10, 30);
-
-        // f.fill('red');
-        f.sphere();
-        p.image(f, 0, 0);
+        fragSrc = `
+         precision highp float;
+         void main() {
+           gl_FragColor = vec4(1.0, 1.0,  0.0, 1.0);
+         }`;
+         s = p.createFilterShader(fragSrc);
+         p.fill('red');
+         p.rect(0,0,100,100)
+         p.filter(s);
+         p.filter(p.POSTERIZE, 64);
+        //  p.filter(p.POSTERIZE,64);
+        //  p.filter(s);
+        };
+        
+        p.draw = function () {
+        p.image(f,0,0);
       };
     };
 
diff --git a/test/unit/webgl/p5.RendererGL.js b/test/unit/webgl/p5.RendererGL.js
index 8fd8b0fa06..5843e36d2f 100644
--- a/test/unit/webgl/p5.RendererGL.js
+++ b/test/unit/webgl/p5.RendererGL.js
@@ -412,18 +412,6 @@ suite('p5.RendererGL', function() {
       assert.doesNotThrow(testDefaultParams, 'this should not throw');
     });
 
-    test('filter() uses WEBGL implementation behind main P2D canvas', function() {
-      let renderer = myp5.createCanvas(3,3);
-      myp5.filter(myp5.BLUR);
-      assert.isDefined(renderer.filterGraphicsLayer);
-    });
-
-    test('filter() can opt out of WEBGL implementation', function() {
-      let renderer = myp5.createCanvas(3,3);
-      myp5.filter(myp5.BLUR, false);
-      assert.isUndefined(renderer.filterGraphicsLayer);
-    });
-
     test('filters make changes to canvas', function() {
       myp5.createCanvas(20,20);
       myp5.circle(10,10,12);