srp

(stands for software rendering pipeline)

Highly inspired by OpenGL API and made only for learning purposes, this is my first serious project in C (still WIP at the moment) and my first project in the field of computer graphics. The only dependency is stb_image. You probably do not want to use this in production code!

This is a rendering pipeline written fully in software that uses only the CPU for computation. It features:

• Fully programmable vertex and fragment shaders
• A small math library with vector and matrix structures to use in shader programming
• Texture mapping
• Shader uniforms
• Affine attribute interpolation

Read the documentation for master branch here, or build the documentation yourself (see Building section)

Building

git clone https://www.github.com/fahlerile/srp
mkdir srp/build
cd srp/build
cmake .. -D CMAKE_BUILD_TYPE=Release
make
cd bin

You can also build the examples with -D BUILD_EXAMPLES=1 and the documentation with -D BUILD_DOCS=1 arguments passed to cmake. Building the documentation requires having dot binary in PATH.

Similar/related projects

• https://github.com/rswinkle/PortableGL
• https://github.com/NotCamelCase/SoftLit
• https://github.com/nikolausrauch/software-rasterizer
• https://github.com/niepp/srpbr

And a lot more... Here I mentioned only those projects on which I looked at as a reference while making this one. If you need more similar projects, see this and this.

References

• General Computer Graphics concepts:
  • https://www.scratchapixel.com/
  • https://learnopengl.com/
• Triangle rasteization:
  • https://www.youtube.com/watch?v=k5wtuKWmV48
  • https://dl.acm.org/doi/pdf/10.1145/54852.378457
  • https://acta.uni-obuda.hu/Mileff_Nehez_Dudra_63.pdf
  • https://www.montis.pmf.ac.me/allissues/47/Mathematica-Montisnigri-47-13.pdf
• Perspective-correct interpolation:
  • https://www.comp.nus.edu.sg/%7Elowkl/publications/lowk_persp_interp_techrep.pdf
  • https://www.youtube.com/watch?v=F5X6S35SW2s

And many, many more, all of which I will not find anymore...

TODO

Features

• Add interpolation with perspective correction
• Fix rasterization rules (see the gaps between triangles in 03_spinning_textured_cube example)
• Implement other primitives (lines, points, lines/triangles strip/adjacency etc.)
• Implement interpolation for types other than double (shouldn't it just be double and float?)
• Add multisampling
• Advanced texture techniques:
  • (Bi)linear filtering
  • Mipmapping
  • Anisotropic filtering
  • Transparent textures?

Optimization

• Are vec and mat functions inlined by the compiler? Should they be? Are mat or vec ever passed by-value?
• Use a profiler to find bottlenecks in frequently-used functions
• Draw primitives in parallel (OpenMP)

What I learned

This is a section specially for my portfolio, so feel free to skip it. Well, I learned:

• Some C programming techniques and library design
• Importance of having a plan, an end goal:
  • This project started as something completely different from what it is now
• Basic Git workflow
• The importance of atomic (if it is possible) commits and meaningful commit names
• Premature optimization and optimization without measuring really is the root of all evil
• Importance of readable code and comments where they are needed