What I Built

The Ghost pacer glasses use an OLED microprojector to reflect an image off of a partially transparent mirror in front of the user's eye. My job was to write the code that transformed abstract representations of what the user should see into actual images on that microprojector. Specifically, this entailed transforming both 3D and 2D assets into Open GL ES 2.0 vertex buffers that could then be loaded into the GPUs draw buffer and rendered to the screen.

The Ghost Pacer logo projected in the glasses' screen

Hardware Constraints

The glasses were extremely lightweight. In fact, one of the things that makes them remarkable is how small the overall package is. We achieved this form factor by building totally custom hardware from the ground up. However, this also comes with drawbacks. In particular, the glasses are forced to use an underpowered GPU to display the augmented reality scene. As a result, the graphics code had to be very low level and extremely optimized to run on our chipset. I had to take care to not waste any memory or compute power, so all the code I wrote was in C and C++. Since we were so constrained by performance, and since the chipset was so exotic and unsupported by prebuilt solutions, I had to write almost everything from scratch. This included the code for rendering 2D shapes, loading textures from image files, shading 3D models in the GPU, and an entire subsystem based around these extremely low-level processes.

The Ghost Pacer glasses side view (v1.5)

Results

My graphics engine powered two versions of the Ghost Pacer glasses (including the most recent one). It allowed us to display complex User interfaces with backgrounds, shapes, buttons, icons, multiple 3D models, and a host of other capabilities that would've been impossible without it. It helped us secure development contracts and it helped us impress potential customers in demos. I wish I could say more, and maybe someday in the future I'll be able to...