A CPU Rasterizer written in Zig during my free time for fun and to learn.
- Forward Renderer
- PBR Shading (Albedo, Metallic, Roughness, Transmission, Emissive)
- Lights: Area, Point, Directional
- Texture (Bilinear sampling)
- Transmission shading (with crude screen-space refraction)
- Exports to
.hdr(HDR range) and.png(SDR range) - glTF format (W.I.P, doesn't support .glb file, spotlight, among some other things)
Zig version: 0.15.2
In project root, do:
zig build -Doptimize=ReleaseFast
Find the exe in zig-out/bin named ZigCPURasterizer.
For interactive mode:
./ZigCPURasterizer --interactive -i path/to/demo.gltf
For static image exports (two format are supported .png and .hdr):
./ZigCPURasterizer -i path/to/demo.gltf -o image.png
Screenshot:
The Junk Shop:
Lumberyard Bistro:
Damaged Helmet:
Converting .hdr file to .avif (supported by both Safari/Chrome) or .jxl (supported by Safari only) to display on web.
ffmpeg -i camera_0.hdr \
-vf "format=gbrpf32le,exposure=1,zscale=tin=linear:pin=bt709:rin=full:t=smpte2084:p=smpte432:r=full" \
-c:v libaom-av1 -crf 10 -cpu-used 4 \
-color_primaries smpte432 -color_trc smpte2084 -colorspace bt2020nc \
test.avif
ffmpeg -i camera_0.hdr \
-vf "format=gbrpf32le,exposure=1,zscale=tin=linear:pin=bt709:rin=full:t=smpte2084:p=smpte432:r=full" \
-c:v libjxl \
-color_primaries smpte432 -color_trc smpte2084 -colorspace bt2020nc \
test.jxl
Some refs:
- https://www.scratchapixel.com/ (Huge thanks)
- http://acta.uni-obuda.hu/Mileff_Nehez_Dudra_63.pdf
- https://fgiesen.wordpress.com/2013/02/10/optimizing-the-basic-rasterizer/
- https://www.cs.drexel.edu/~david/Classes/Papers/comp175-06-pineda.pdf
Lion (Prev | ReleaseFast): Frame Time (Min - Max): 22 - 31 Avg. Time (Min - Max): 26.68868 - 30.67742
Lion (New | ReleaseFast): Frame Time (Min - Max): 19 - 27 Avg. Time (Min - Max): 21.70513 - 23.67742
Lion (Prev | Debug): Frame Time (Min - Max): 106 - 142 Avg. Time (Min - Max): 122.10526 - 128.07500
Lion (New | Debug): Frame Time (Min - Max): 92 - 118 Avg. Time (Min - Max): 107.01357 - 112.09677
Note: There wasn't any (apparent) performance improvement from using new datastructure compared to used zigimg directly. Most of the improvements is from moving image operation (normal map [0, 1] -> [-1, 1] and albedo's srgb -> linear) conversions.
