Use Geometry Shader to generate the Mesh #5

EmaMaker · 2023-07-19T13:19:00+02:00

EmaMaker commented

2023-07-19 13:19:00 +02:00

Instead of using greedy meshing to generate full quads on the CPU, greedy meshing only generates a cloud of points corresponding to the bottom-left corner of the quad. Three separate buffers are used to store information on vertex position, extent of the quad (in x,y,z) and other info about the texture and normal (block type, whether it's a backface or not).

Complete information about vertex normal and texture coordinates are derived from backface and extent data.
The other 3 vertices are generated on the GPU with a geometry shader using data from the cloud of points.

This means that a lot less data is sent to the GPU about each mesh, and this brings down VRAM usage:
In the standard world (seeds 12345, CHUNK_SIZE=32, RENDER_DISTANCE=16, camera centered at (512, 80, 512) ):

W/out geometry shader: 82MB
w/ geometry shader: 20MB

Instead of using greedy meshing to generate full quads on the CPU, greedy meshing only generates a cloud of points corresponding to the bottom-left corner of the quad. Three separate buffers are used to store information on vertex position, extent of the quad (in x,y,z) and other info about the texture and normal (block type, whether it's a backface or not). Complete information about vertex normal and texture coordinates are derived from backface and extent data. The other 3 vertices are generated on the GPU with a geometry shader using data from the cloud of points. This means that a lot less data is sent to the GPU about each mesh, and this brings down VRAM usage: In the standard world (seeds 12345, CHUNK_SIZE=32, RENDER_DISTANCE=16, camera centered at (512, 80, 512) ): W/out geometry shader: 82MB w/ geometry shader: 20MB

EmaMaker added 6 commits 2023-07-19 13:19:01 +02:00

bff9e6ad4f move normal data to own array

ea036f403c shader.hpp: add geometry shader support

e7fc35ec47 create chunk mesh as cloud of points

54c7fa172f generate mesh from points using geometry shader

950c43b163 refactor chunk meshing routine

4fa89fd2f5 gamma correction

EmaMaker merged commit 8313ee97bc into main

2023-07-19 13:19:19 +02:00

EmaMaker referenced this issue from a commit

2023-07-19 13:19:20 +02:00

Merge pull request 'Use Geometry Shader to generate the Mesh' (#5) from vram-reduce into main