I want to create shaders but I need a tool to create and see the visual result before I put them into my game. As to determine if there is something wrong with my game or if it's something with the shader I created. I've looked at some like Render Monkey and OpenGL Shader Designer from what I recall of Render Monkey it had a way to define your own attributes (now as "in" for vertex shaders >= 330) easily though I can't remember to what extent. Shader Designer requires a plugin that I didn't even bother to look at creating cause it's an external process and plugin. Are there any tools out there that support a scripting language and I could easily provide specific input such as float movement = sin(elapsedTime()); and then define in float movement; in the vertex shader ?

It'd be cool if anyone could share how they develop shaders, if they just code away and then plug it into their game hoping to get the result they wanted.