5.1.3.2 Surface appearance
Digital Alphabot’s surface appearance leverages a common environment mapping technique known as cube mapping optimized for real-time rendering [8]. To match the appearance of the robot in physical reality, photographs of the physical character wearing each symbol are used as the source for the cube maps. A straight-forward, stock OpenGL Shading Language (GLSL) shader running on the graphics processing unit (GPU) permits the character’s surface appearance to adapt to changing lighting conditions in the world, further integrating digital Alphabot into the final blended reality rendered scene [20].