A 3D object viewer that runs on a bare-metal Raspberry Pi (no standard libraries).

Created for the Stanford CS107e final project (Winter 2021).

Ari Webb (AriWebb)

Tejas Narayanan (tnarayanan)

• Fast triangle rendering using z-buffers
• Directional lighting
• Loading .obj files from file system
• Moving camera around model using arrow keys

Upcoming

• GPU acceleration

Requires the libpi set of libraries built in CS107e, which includes implementations of standard library methods as well as some extras:

• Strings (strlen, strlcat, printf)
• Memory (memset, memcpy, malloc)
• GPIO
• Graphics (mailbox, framebuffer, drawing)
• Keyboard (PS2 interface)

• Pat Hanrahan's wonderful advice!
• Perspective projection: https://www.scratchapixel.com/lessons/3d-basic-rendering/rendering-3d-scene-overview/perspective-projection
• Camera/view matrices: https://www.3dgep.com/understanding-the-view-matrix/#Look_At_Camera

• Square root calculation method: https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method

• Monkey: Blender default shape (https://www.blender.org/)
• Wolf: https://free3d.com/3d-model/low-poly-wolf-71850.html
• Goat: https://free3d.com/3d-model/low-poly-goat-35241.html
• Cat: https://free3d.com/3d-model/low-poly-cat-46138.html
• Deer: https://free3d.com/3d-model/low-poly-deer-87801.html

• VideoCore IV assembler/example programs: https://github.com/hermanhermitage/videocoreiv
  • The tinyasm module (GPU assembler) is from this repository. No additional changes were made.
• Mailbox properties documentation: https://github.com/raspberrypi/firmware/wiki/Mailbox-property-interface
• Example of bare metal program that uses mailbox to get Raspberry Pi's serial number: https://github.com/bztsrc/raspi3-tutorial/tree/master/04_mailboxes
  • Used this code to understand how to use the mailbox to communicate with the GPU. No code was taken from this repository.
• Example program to peek/poke a memory address using the GPU: https://github.com/ali1234/vcpoke
  • Used this code to understand the process of executing a program on the GPU. No code was taken from this repository.

Video demo: https://drive.google.com/file/d/1jsQI91-H1OuIeEY4wmy1Li1u-xQmRkDC/view?usp=sharing

Suzanne, the default Blender monkey:

An orange-colored wolf:

A z-buffer demonstration on the wolf model. Lighter colors are closer to the camera than darker colors.

A deer: