`nx_cull_lod.nx` source

1// nx_cull_lod.nx -- P3 RESPONSIVENESS: sovereign CULLING + LOD, the "do less work" lever that the
2// research named as the top win you fully own on weak hardware. Back-face + distance + frustum culling
3// drop triangles BEFORE the pixel stage; LOD lowers detail with distance. Pure integer; the work it
4// avoids is MEASURED (survivor count + LOD-weighted work vs brute-force). 100% sovereign. license_tier: ORIGINAL
5
6// visible? back-face (normal_z<=0 faces away), distance (dist>far), frustum (sx outside [0,w)) all cull.
7func cl_visible(nz: i64, dist: i64, sx: i64, far: i64, w: i64) -> i64 {
8    if nz <= 0 { return 0 }
9    if dist > far { return 0 }
10    if sx < 0 { return 0 }
11    if sx >= w { return 0 }
12    return 1
13}
14
15// LOD weight: near=4 (full detail), mid=2, far=1 (coarse) -- fewer triangles per object with distance.
16func cl_lod_weight(dist: i64, mid: i64, far: i64) -> i64 {
17    if dist <= mid { return 4 }
18    if dist <= far { return 2 }
19    return 1
20}
21
22// total render work = sum of LOD weights over VISIBLE triangles (what the engine actually pays).
23func cl_work(nz: *i64, dist: *i64, sx: *i64, n: i64, far: i64, w: i64, mid: i64) -> i64 {
24    var sum: i64 = 0
25    var i: i64 = 0
26    while i < n {
27        if cl_visible(nz[i], dist[i], sx[i], far, w) == 1 { sum = sum + cl_lod_weight(dist[i], mid, far) }
28        i = i + 1
29    }
30    return sum
31}
32
33// brute force: every triangle at full detail (the no-culling, no-LOD baseline).
34func cl_brute(n: i64) -> i64 { return n * 4 }
35
36func cl_survivors(nz: *i64, dist: *i64, sx: *i64, n: i64, far: i64, w: i64) -> i64 {
37    var s: i64 = 0
38    var i: i64 = 0
39    while i < n { if cl_visible(nz[i], dist[i], sx[i], far, w) == 1 { s = s + 1 } i = i + 1 }
40    return s
41}
nx_cull_lod.nx source

`nx_cull_lod.nx` source
