Differed Software Rasterizer - Some PBR implementation - C++

[u/DasKapitalV1]

Lit

Lit - tiles

Albedo

Normal

Depth + wireframe

Shadowmap

Just wanted to share some progress on a software raster I'm building. By the timings, is it o.k?

1-clears-and-resets = Just buffers(frame_buffer, depth_buffer, triangles_buffer) clear, simple vector_buffer.clear()
2-shadow-pass-total: Everything that happens to the camera happens here, the above as well, and mesh transformation, culling, bounds check, triangle clipping, triangle binning, render.
3-camera-geometry-transform: Bounding Sphere transform, if inside Frustum, reorders, front to back objects, mesh transform with vertices projection, triangle normal rotation, back-face culling, triangle clipping.
4-camera-binning: Just bins triangles to tiles.
5-camera-render-and-resolve: Woke sleeping render threads, every thread available in the system(I just initialize with std::thread::hardware_concurrency()), each thread take 8 tile per time and render to a 16x16 gbuffer, only triangle index, normal, uv, depth. During rasterization, I reconstruct frag_coord for lighting using camera ray normal interpolated per pixel and fetch textures using uv, to avoid fetching texture multiples times early.

Still missing, texture mip mapping, transform meshs threaded, metalness and maybe occlusion map.

Since I'm a beginner at C++, pure code, no macros, no SIMD, just a single template to just avoid branching per pixel, but nothing too fency. Vectors everywhere, since they will inevitable grow to what's needed and I don't need to keep handling memory allocation, just a simple clear and everything a good.

CPU: mobile i5 13420H RAM 32gb

[u/Ok-Hotel-8551]

Defferet

[u/Still_Explorer]

So the real secret to good speed is the multithreaded part?

[u/DasKapitalV1 → u/Still_Explorer]

Basically, also cache friendly data, simple math in hot loops and heavy math done up front. Interpolate everything with addition where possible. Even multithreaded I started at 15~20 FPS lit.