Raymarcher

A bare-bones raymarch engine featuring small number of primitives. Programmed from scratch in C++, using NVIDIA Cuda for GPU parallelisation, and SDL2 to draw the graphics to the screen. Video Demo

Positive Features:

• Rendered my website's header image
• Draws 3D graphics to the screen
• Acceptable framerates at lower resolutions
  • Pixel skipping enables larger screen sizes with low resolutions

Negative Features:

• Framerate is unusably slow at desired framerates
  • Current workaround is to skip drawing a number of pixels. If the pixels don't line up in neat rows, the human eye can fill in the gaps fairly convincingly. This means that we can get a 100%+ improvement in FPS with a moderate drop in clarity.
  • Comparison:
• Lighting produces dark spots at certain ray angles.

Lessons Learned:

• Use libraries for the purpose they're designed for.
  • CUDA is good for computational applications but kernel initialisation and memory copy times were too slow for enjoyable realtime use.
  • The program would likely have ran a lot faster if it had been written in an OpenGL shader.
• Implicit conversions take a lot of time.
  • Was able to get 100% FPS increase by removing implicit double -> float conversions.

Possible Extensions:

• Use semaphores to allow concurrent CPU and GPU processing.
  • Currently program crashes because they try to access the same memory.
• Implement a persistent kernel
  • Avoids waiting for kernel initialisation each frame.
  • Enables CPU and GPU concurrency.

Screenshots

• Pyramid:

• Balls