diff --git a/packages/shader/shader.mjs b/packages/shader/shader.mjs
index 8d9f0430c..6b1864b38 100644
--- a/packages/shader/shader.mjs
+++ b/packages/shader/shader.mjs
@@ -24,6 +24,8 @@ out vec4 oColor;
 uniform float iTime;
 uniform vec2 iResolution;
 
+#define STRUDEL 1
+
 ${code}
 
 void main(void) {
@@ -65,6 +67,7 @@ export function setUniform(instanceName, name, value, position) {
     return;
   }
 
+  // console.log("setUniform: ", name, value, position)
   const uniform = instance.uniforms[name];
   if (uniform) {
     if (uniform.count == 0) {
@@ -91,6 +94,8 @@ function updateUniforms(drawFrame, elapsed, uniforms) {
   Object.values(uniforms).forEach((uniform) => {
     const value =
       uniform.count == 0 ? uniform.mod.get(elapsed) : uniform.value.map((_, i) => uniform.mod[i].get(elapsed));
+
+    // console.log("updateUniforms:", uniform.name, value)
     // Send the value to the GPU
     drawFrame.uniform(uniform.name, value);
   });
@@ -138,9 +143,7 @@ function setupCanvas(name) {
 async function initializeShaderInstance(name, code) {
   // Setup PicoGL app
   const ctx = setupCanvas(name);
-  console.log(ctx);
   const app = PicoGL.createApp(ctx);
-  app.resize(400, 300);
 
   // Setup buffers
   const resolution = new Float32Array([ctx.canvas.width, ctx.canvas.height]);
diff --git a/packages/shader/uniform.mjs b/packages/shader/uniform.mjs
index 903988554..12627aa68 100644
--- a/packages/shader/uniform.mjs
+++ b/packages/shader/uniform.mjs
@@ -7,72 +7,104 @@ This program is free software: you can redistribute it and/or modify it under th
 import { register, logger } from '@strudel/core';
 import { setUniform } from './shader.mjs';
 
-/**
- * Update a shader. The destination name consist of
- *
- * - the uniform name
- * - optional array mapping, either a number or an assignment mode ('seq' or 'pitch')
- *
- * @name uniform
- * @example
- * s("bd").uniform("iColor")
- * @example
- * s("bd").uniform("iColors:seq")
- * @example
- * note("c3 e3").uniform("iMorph:pitch")
- */
 function parseUniformTarget(name) {
-  if (typeof name === 'string') return { name, mapping: 'single', position: 0 };
+  if (typeof name === 'string') return { name, position: 0 };
   else if (name.length == 2) {
-    const mapping = typeof name[1] === 'string' ? name[1] : 'single';
-    const position = typeof name[1] === 'string' ? null : name[1];
-    return {
-      name: name[0],
-      mapping,
-      position,
-    };
+    let position = null;
+    if (typeof name[1] === 'number') position = name[1];
+    else if (name[1] == 'random') position = Math.floor(Math.random() * 1024);
+    else if (name[1] != 'seq') throw 'Unknown mapping: ' + name[1];
+    return { name: name[0], position };
   }
 }
 
 // Keep track of the pitches value per uniform
-let _pitches = {};
+let _uniforms = {};
+function getNextPosition(name, value) {
+  // Initialize uniform state
+  if (!_uniforms[name]) _uniforms[name] = { _count: 0 };
+  const uniform = _uniforms[name];
+
+  // Set a new position when the value changes
+  if (uniform._last != value) {
+    uniform._last = value;
+    uniform._count++;
+  }
+  return uniform._count;
+}
+
+/**
+ * Update a shader. The destination name consist of
+ *
+ * - the uniform name
+ * - optional array mapping, either a number or an assignment mode ('seq' or 'random')
+ *
+ * @name uniform
+ * @example
+ * pan(sine.uniform("iColor"))
+ * @example
+ * gain("<.5 .3>".uniform("rotations:seq"))
+ */
 export const uniform = register('uniform', (target, pat) => {
   // TODO: support multiple shader instance
   const instance = 'default';
 
-  // Decode the uniform defintion
+  // Decode the uniform target defintion
   const uniformTarget = parseUniformTarget(target);
 
-  // Get the pitches
-  if (!_pitches[uniformTarget.name]) _pitches[uniformTarget.name] = { _count: 0 };
-  const pitches = _pitches[uniformTarget.name];
+  return pat.withValue((v) => {
+    // TODO: figure out why this is called repeatedly when changing values. For example, on first call, the last value is passed.
+    if (typeof v === 'number') {
+      const position =
+        uniformTarget.position === null ? getNextPosition(uniformTarget.name, v) : uniformTarget.position;
+      setUniform(instance, uniformTarget.name, v, position);
+    } else {
+      console.error('Uniform applied to a non number pattern');
+    }
+    return v;
+  });
+});
+
+function getNotePosition(name, value) {
+  // Initialize uniform state
+  if (!_uniforms[name]) _uniforms[name] = {};
+  const uniform = _uniforms[name];
+
+  const note = value.note || value.n || value.sound || value.s;
+  if (uniform[note] === undefined) {
+    // Assign new value, the first note gets 0, then 1, then 2, ...
+    uniform[note] = Object.keys(uniform).length;
+  }
+  return uniform[note];
+}
+
+/**
+ * Update a shader with note-on event. The destination name consist of
+ *
+ * - the uniform name
+ * - optional array position, default to randomly assigned position based on the note or sound.
+ *
+ * @name uniformTrigger
+ * @example
+ * pan(sine.uniform("iColor"))
+ * @example
+ * gain("<.5 .3>".uniform("rotations:seq"))
+ */
+export const uniformTrigger = register('uniformTrigger', (target, pat) => {
+  // TODO: support multiple shader instance
+  const instance = 'default';
+
+  // Decode the uniform target defintion
+  const uniformTarget = parseUniformTarget(target);
 
   return pat.onTrigger((time_deprecate, hap, currentTime, cps, targetTime) => {
-    // TODO: figure out how to get the desired value, e.g. is this pattern for pan, gain, velocity, ...
-    const value = hap.value ? hap.value.gain || 1.0 : 1.0;
+    const position =
+      uniformTarget.position === null ? getNotePosition(uniformTarget.name, hap.value) : uniformTarget.position;
 
-    // Get the uniform mapping position
-    let position = null;
-    if (uniformTarget.mapping == 'pitch') {
-      // Assign one position per pitch
-      const note = hap.value.note || hap.value.s;
-      if (pitches[note] === undefined) {
-        // Assign new value, the first note gets 0, then 1, then 2, ...
-        pitches[note] = Object.keys(pitches).length;
-      }
-      position = pitches[note];
-    } else if (uniformTarget.mapping == 'seq') {
-      console.log('HERE', pitches);
-      // Assign a new position per event
-      position = pitches._count++;
-    } else if (uniformTarget.mapping == 'single') {
-      // Assign a fixed position
-      position = uniformTarget.position;
-    } else {
-      console.error('Unknown uniform target', uniformTarget);
-    }
+    // TODO: support custom value
+    const value = 1.0;
 
     // Update the uniform
-    if (position !== null) setUniform(instance, uniformTarget.name, value, position);
+    setUniform(instance, uniformTarget.name, value, position);
   }, false);
 });