Shed some light on what these shaders are doing, so to speak.

interface/resources/shaders/iris.frag

@@ -15,7 +15,10 @@ uniform sampler2D texture;
 varying vec4 normal;
 
 void main(void) {
+    // compute the specular component (sans exponent) based on the normal OpenGL lighting model
     float specular = max(0.0, dot(normalize(gl_LightSource[0].position + vec4(0.0, 0.0, 1.0, 0.0)), normalize(normal)));
+    
+    // modulate texture by diffuse color and add specular contribution
     gl_FragColor = vec4(gl_Color.rgb * texture2D(texture, gl_TexCoord[0].st).rgb +
         pow(specular, gl_FrontMaterial.shininess) * gl_FrontLightProduct[0].specular.rgb, 1.0);
 }

interface/resources/shaders/iris.vert

@@ -12,9 +12,17 @@
 varying vec4 normal;
 
 void main(void) {
+
+    // transform and store the normal for interpolation
     normal = normalize(gl_ModelViewMatrix * vec4(gl_Normal, 0.0));
+    
+    // compute standard diffuse lighting per-vertex
     gl_FrontColor = gl_Color * (gl_LightModel.ambient + gl_LightSource[0].ambient +
         gl_LightSource[0].diffuse * max(0.0, dot(normal, gl_LightSource[0].position)));
+    
+    // copy the tex coordinate for interpolation
     gl_TexCoord[0] = gl_MultiTexCoord0;
+    
+    // use standard pipeline transform
     gl_Position = ftransform();
 }