@@ -0,0 +1,46 @@
+// Use of custom vertex attributes.
+// Inspired by 
+// http://pyopengl.sourceforge.net/context/tutorials/shader_4.html
+
+PShader sh;
+
+void setup() {
+  size(640, 360, P3D);
+  sh = loadShader("frag.glsl", "vert.glsl");
+  shader(sh);
+  noStroke();
+}
+
+void draw() {
+  background(255);
+  
+  sh.set("tween", map(mouseX, 0, width, 0, 1));
+  
+  translate(width/2, height/2, 0);
+  rotateX(frameCount * 0.01);
+  rotateY(frameCount * 0.01);
+  
+  fill(150);
+  beginShape(QUADS);
+  float d = 10;
+  for (int x = -500; x < 500; x += d) {
+    for (int y = -500; y < 500; y += d) {
+      fill(255 * noise(x, y));
+      attribPosition("tweened", x, y, 100 * noise(x, y));
+      vertex(x, y, 0);
+     
+      fill(255 * noise(x + d, y));
+      attribPosition("tweened", x + d, y, 100 * noise(x + d, y));
+      vertex(x + d, y, 0);
+      
+      fill(255 * noise(x + d, y + d));
+      attribPosition("tweened", x + d, y + d, 100 * noise(x + d, y + d)); 
+      vertex(x + d, y + d, 0);
+      
+      fill(255 * noise(x, y + d));
+      attribPosition("tweened", x, y + d, 100 * noise(x, y + d));
+      vertex(x, y + d, 0);    
+    }
+  }
+  endShape();
+}
@@ -0,0 +1,5 @@
+varying vec4 vertColor;
+
+void main() {
+  gl_FragColor = vertColor;
+}
@@ -0,0 +1,14 @@
+uniform mat4 transformMatrix;
+uniform float tween;
+
+attribute vec4 position;
+attribute vec4 tweened;
+attribute vec4 color;
+
+varying vec4 vertColor;
+
+void main() {
+  gl_Position = transformMatrix * ((1- tween) * position + tween * tweened);
+    
+  vertColor = color;
+}