.GDP file extension

This is the basic program to work with .GDP extension

GUI Design Studio Pro

GUI Design Studio Pro Project

GUI Design Studio is a code-free, drag and drop user interface design and prototyping tool for creators of web, desktop, mobile, and embedded software applications. You can use this program to design mock-ups and create project proposals. It comes with more than 120 design elements to help you speed-up your projects... (more)

The program works with the following extensions: gui, gdp

.GDP extension is also supported by the following program:

Shader Designer

Shader Designer ShaderDesigner Project Workspace

Is designed to aid in the task of authoring GLSL vertex and fragment shaders.