elias/voxel-simulation
1
0
Fork 0
mirror of https://github.com/eliasstepanik/voxel-simulation.git synced 2026-01-10 21:38:29 +00:00
Code Issues Packages Projects Releases Wiki Activity

Implement greedy meshing shader

Browse Source
This commit is contained in:
Elias Stepanik 2025-06-13 12:24:23 +02:00
parent eb34a16a0a
commit 6c4b125ea9
1 changed files with 141 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

144
client/assets/shaders/greedy_meshing.wgsl
View File

@ -8,7 +8,7 @@ struct Params {
axis: u32,
dir: i32,
slice: u32,
n: vec3<f32>,
_pad: u32,
};
struct Vertex {
@ -25,8 +25,146 @@ struct Vertex {
const N: u32 = 16u;
const MASK_LEN: u32 = N * N;
fn voxel_index(p: vec3<i32>) -> u32 {
return u32(p.x) * N * N + u32(p.y) * N + u32(p.z);
}
fn voxel_filled(p: vec3<i32>) -> bool {
return p.x >= 0 && p.x < i32(N) && p.y >= 0 && p.y < i32(N) && p.z >= 0 && p.z < i32(N) && voxels[voxel_index(p)] != 0u;
}
@compute @workgroup_size(1)
fn main(@builtin(global_invocation_id) id: vec3<u32>) {
// TODO: implement full greedy algorithm.
// This shader currently only reserves space for CPU-driven meshing.
var mask: array<bool, MASK_LEN>;
var visited: array<bool, MASK_LEN>;
// Iterate over all axes and both face directions.
for (var axis: u32 = 0u; axis < 3u; axis = axis + 1u) {
for (var dir_idx: u32 = 0u; dir_idx < 2u; dir_idx = dir_idx + 1u) {
let dir: i32 = select(-1, 1, dir_idx == 1u);
for (var slice: u32 = 0u; slice < N; slice = slice + 1u) {
// Build mask for this slice.
for (var u: u32 = 0u; u < N; u = u + 1u) {
for (var v: u32 = 0u; v < N; v = v + 1u) {
var cell = vec3<i32>(0, 0, 0);
var neighbor = vec3<i32>(0, 0, 0);
if axis == 0u {
cell = vec3<i32>(i32(slice), i32(u), i32(v));
neighbor = cell + vec3<i32>(dir, 0, 0);
} else if axis == 1u {
cell = vec3<i32>(i32(v), i32(slice), i32(u));
neighbor = cell + vec3<i32>(0, dir, 0);
} else {
cell = vec3<i32>(i32(u), i32(v), i32(slice));
neighbor = cell + vec3<i32>(0, 0, dir);
}
let i = u * N + v;
mask[i] = voxel_filled(cell) && !voxel_filled(neighbor);
visited[i] = false;
}
}
// Greedy merge.
for (var u0: u32 = 0u; u0 < N; u0 = u0 + 1u) {
for (var v0: u32 = 0u; v0 < N; v0 = v0 + 1u) {
let i0 = u0 * N + v0;
if !mask[i0] || visited[i0] {
continue;
}
var width: u32 = 1u;
loop {
if u0 + width >= N || !mask[u0 + width * N + v0] || visited[u0 + width * N + v0] {
break;
}
width = width + 1u;
}
var height: u32 = 1u;
outer: loop {
if v0 + height >= N {
break;
}
for (var du: u32 = 0u; du < width; du = du + 1u) {
let idx = (u0 + du) * N + v0 + height;
if !mask[idx] || visited[idx] {
break outer;
}
}
height = height + 1u;
}
for (var du: u32 = 0u; du < width; du = du + 1u) {
for (var dv: u32 = 0u; dv < height; dv = dv + 1u) {
visited[(u0 + du) * N + v0 + dv] = true;
}
}
// Compute base world-space position.
var base = params.origin;
if axis == 0u {
base = base + vec3<f32>(f32(slice) + (dir > 0 ? 1.0 : 0.0), f32(u0), f32(v0)) * params.step;
} else if axis == 1u {
base = base + vec3<f32>(f32(v0), f32(slice) + (dir > 0 ? 1.0 : 0.0), f32(u0)) * params.step;
} else {
base = base + vec3<f32>(f32(u0), f32(v0), f32(slice) + (dir > 0 ? 1.0 : 0.0)) * params.step;
}
let size = vec2<f32>(f32(width) * params.step, f32(height) * params.step);
var normal = vec3<f32>(0.0, 0.0, 0.0);
var u_unit = vec3<f32>(0.0, 0.0, 0.0);
var v_unit = vec3<f32>(0.0, 0.0, 0.0);
if axis == 0u {
normal = vec3<f32>(f32(dir), 0.0, 0.0);
u_unit = vec3<f32>(0.0, 1.0, 0.0);
v_unit = vec3<f32>(0.0, 0.0, 1.0);
} else if axis == 1u {
normal = vec3<f32>(0.0, f32(dir), 0.0);
u_unit = vec3<f32>(0.0, 0.0, 1.0);
v_unit = vec3<f32>(1.0, 0.0, 0.0);
} else {
normal = vec3<f32>(0.0, 0.0, f32(dir));
u_unit = vec3<f32>(1.0, 0.0, 0.0);
v_unit = vec3<f32>(0.0, 1.0, 0.0);
}
let p0 = base;
let p1 = base + u_unit * size.x;
let p2 = base + u_unit * size.x + v_unit * size.y;
let p3 = base + v_unit * size.y;
let vi = atomicAdd(&counts[0], 4u);
vertices[vi] = Vertex(pos: p0, normal: normal, uv: vec2<f32>(0.0, 1.0));
vertices[vi + 1u] = Vertex(pos: p1, normal: normal, uv: vec2<f32>(1.0, 1.0));
vertices[vi + 2u] = Vertex(pos: p2, normal: normal, uv: vec2<f32>(1.0, 0.0));
vertices[vi + 3u] = Vertex(pos: p3, normal: normal, uv: vec2<f32>(0.0, 0.0));
let ii = atomicAdd(&counts[1], 6u);
if dir > 0 {
indices[ii] = vi;
indices[ii + 1u] = vi + 1u;
indices[ii + 2u] = vi + 2u;
indices[ii + 3u] = vi + 2u;
indices[ii + 4u] = vi + 3u;
indices[ii + 5u] = vi;
} else {
indices[ii] = vi;
indices[ii + 1u] = vi + 3u;
indices[ii + 2u] = vi + 2u;
indices[ii + 3u] = vi + 2u;
indices[ii + 4u] = vi + 1u;
indices[ii + 5u] = vi;
}
}
}
}
}
}
}