vercidium / voxel-mesh-generation

Optimised voxel mesh generation, written in C# and open sourced from the Vercidium Engine.

This Repository Is Outdated

The new repository is available here, which features faster greedy meshing and a standalone renderer.

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voxel-mesh-generation

Optimised voxel mesh generation, written in C# and open sourced from the game Sector's Edge.

Overview

This repository contains C# code for mesh generation on the CPU, setting up VBO and VAOs for OpenGL rendering, as well as fragment and vertex shaders.

The explanation and visualisation of this mesh generation technique can be found in this blog post. Further optimisation details can be found in this blog post.

Mesh generation and VBO buffering is kept separate so that multiple chunks can be initialised on different threads.

Details

• Chunks are composed of 32x32x32 blocks
• Faces are generated by combining faces in runs along the X and Y axis.
• This algorithm produces ~20% more triangles than greedy meshing and runs ~390% faster
• Block position, texture ID, health and normal are packed into 4 bytes for faster buffering and rendering on the GPU.

Benchmarks

Benchmarks were run with a Ryzen 5 1600 CPU

• ST = Single Threaded Time
• MTT = Multithreaded Time - 12 threads each initialising 1/12th of the map
• CMGT = Chunk Mesh Generation Time

Map Name	Chunk Count	Total STT (ms)	Total MTT (ms)	Average CMGT (ms)
Crashed Freighter	799	421	110	0.527
Soltrium Temple	648	280	73	0.432
Aegis Desert	441	201	51	0.456
Magma Chamber	293	157	38	0.535
Arena	108	30	12	0.278

In Practice

With 16 players per match, multiple chunk meshes must be regenerated every frame. This process has been optimised to ensure the game can be played smoothly on older hardware.

voxel-mesh-generation's Issues

These variable names are not used consistently in the code (in loop it is called minX/maxX and not minXEdge/maxXEdge etc)

voxel-mesh-generation/source/Chunk.cs

Line 70 in 864af31

bool minXEdge, maxXEdge, minZEdge, maxZEdge;

index is not implemented in Block struct

voxel-mesh-generation/source/Chunk.cs

Line 260 in 864af31

return data[access - Constants.ChunkSize].index == 0;