Codea, the iPad app that allows you to create and run code right on your iPad. It has received a major update to allow users even more options than before. The major update allows complete access to GLSL shaders and has a full-featured GLSL shader editor. There's also a new parameter system, documentation browser, and a blend mode.
More Details from the App Store Description:
• Shaders: Full access to GLSL shaders from the mesh class.
• Shader Lab: A full-featured GLSL shader editor with live preview and live variables.
• Camera: Stream from the cameras on your device straight into a sprite, capture them into an image, or even input them into a shader.
• Brand new Parameter system. Make buttons, color pickers, text boxes and more for the Codea sidebar.
• Vector sprite rendering. You can now load PDF files as sprites, which can be rendered at any size and still look sharp.
• Two great new vector sprite packs by Kenney.nl.
• Tween: The new tween library provides you with easy to use animations, paths, sequences and more.
• Blend Modes: Use the new blendMode() function for additive and multiplicative blending, or even set completely custom blend modes using the advanced parameters.
• Brand new Documentation Browser, copy sample code and use the sidebar for reference as-you-type.
• Completely re-architected Code Editor with built-in API guides.
• New Tools menu from the main screen lets you manage your assets.
• REPL built into the viewer. Type and execute simple expressions while your code is running.