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render3d: a grass kind - the GPU blades' per-kind numbers are a GrassKind record the game hands over (grass_kind_set), not constants

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GrassKind (grass_kind.ludic) carries what grass.ludic, grass_gpu.ludic, grass.vert, grass_cull.comp and
model.frag's BLADE path held as constants: the cell, s0 / d0 / radius, the row bands and rows, the blade
profile (neck, root, swell, tip, bend), the heights, clumps, widths and arch, where it grows (slope, snow,
the photograph's test), the root / tip / gone-to-seed colours, the far tufts, the root occlusion, the
roughness, the sheen and the wind. Its defaults are those constants exactly, so a game that sets nothing
draws as before. The shaders read them as u_gk_* (the cull as five more Params vec4s, 288 bytes);
grass_reset.comp writes each band's index count so a kind of other rows reaches the draw in order.
grass_quality holds the kind to a settings tier (never denser, never farther); R3D_GRASS_* still win.
grass_profile_w / _bend are the one profile, for the meshes and a game's preview. grass.mesh takes only
the cell: the rest of it is an older copy that already differs from grass.vert, left as it draws.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
This commit is contained in:
Orkun ÇAKILKAYA 2026-09-29 19:03:33 +03:00
parent d9a73d63bd
commit e908672034
25 changed files with 335 additions and 75 deletions
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22
packages/ludic.render3d/shaders/grass_cull.comp
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@ -21,6 +21,12 @@ layout(set = 0, binding = 0) uniform Params {
uvec4 base; // each band's first record in Out
uvec4 cap; // ... and how many it holds
vec4 tp; // the page pool (u_tp_dims): tiles a side, height texels a tile, photograph texels a tile, height texels a side
// the grass kind (grass_kind.ludic, grass_params_kind): grass.vert's u_gk_* by the same names
vec4 gk_tall; // tall_min, tall_max, cell_lo, cell_hi
vec4 gk_grow; // tall_far, width, width_far, clump_freq
vec4 gk_clump; // clump_lo, clump_hi, arch, arch_var
vec4 gk_ground; // slope_lo, slope_hi, snow_in, snow_out
vec4 gk_ortho; // ortho_floor, ortho_gain, ortho_green, cell (m)
} pr;
layout(set = 0, binding = 1) readonly buffer Tiles { vec4 tiles[]; }; // corner x/z, indices per cell, cells per side
@ -36,7 +42,7 @@ layout(set = 0, binding = 8) uniform sampler2DArray u_tp_h; // (T +
layout(set = 0, binding = 9) uniform sampler2DArray u_tp_nrm;
layout(set = 0, binding = 10) uniform sampler2DArray u_tp_ortho; // (S + 2)^2 a layer
const float CELL = 4.0; // grass.ludic GRASS_CELL
#define CELL pr.gk_ortho.w // the kind's cell (m)
uint pcg(uint v) { uint s = v * 747796405u + 2891336453u; uint w = ((s >> ((s >> 28u) + 4u)) ^ s) * 277803737u; return (w >> 22u) ^ w; }
float bladeHash(ivec2 cell, int j, int k) {
@ -132,10 +138,10 @@ void main() {
float h3 = bladeHash(ci, j, 2), h4 = bladeHash(ci, j, 3);
float wl = pr.lev.y;
if (pr.lake.z > 0.0) { vec2 q = (xz - pr.lake.xy) / pr.lake.zw; if (dot(q, q) < 1.0) wl = max(wl, pr.lev.x); }
float ok = (1.0 - smoothstep(0.30, 0.55, 1.0 - gn.y)) * smoothstep(0.0, 0.6, ht.r - wl - 0.15) * smoothstep(pr.dens.w - 80.0, pr.dens.w - 200.0, ht.r);
float ok = (1.0 - smoothstep(pr.gk_ground.x, pr.gk_ground.y, 1.0 - gn.y)) * smoothstep(0.0, 0.6, ht.r - wl - 0.15) * smoothstep(pr.dens.w - pr.gk_ground.z, pr.dens.w - pr.gk_ground.w, ht.r);
if (pr.lev.z > 0.5) {
vec3 oc = groundO(huv);
ok *= 0.40 + 0.60 * smoothstep(0.0, 0.025, oc.g - oc.b);
ok *= pr.gk_ortho.x + pr.gk_ortho.y * smoothstep(0.0, pr.gk_ortho.z, oc.g - oc.b);
}
if (h4 > ok) return;
float h = heightSmooth(huv);
@ -143,10 +149,10 @@ void main() {
float ang = bladeHash(ci, j, 6) * 6.2831853;
float grow = spacing / pr.dens.x;
float hh = h3 * h3;
float tall = mix(0.09, 0.60, hh) * mix(0.8, 1.2, hash1(cid * 0.1)) * (1.0 + 0.35 * smoothstep(1.0, 12.0, grow)) * life;
float clump = gnoise(xz * 0.85 + 3.7) * 0.5 + 0.5;
tall *= mix(0.45, 1.40, clump * clump * (3.0 - 2.0 * clump));
float bw = 0.010 * mix(1.0, 0.45 * grow, smoothstep(1.0, 4.0, grow));
float tall = mix(pr.gk_tall.x, pr.gk_tall.y, hh) * mix(pr.gk_tall.z, pr.gk_tall.w, hash1(cid * 0.1)) * (1.0 + pr.gk_grow.x * smoothstep(1.0, 12.0, grow)) * life;
float clump = gnoise(xz * pr.gk_grow.w + 3.7) * 0.5 + 0.5;
tall *= mix(pr.gk_clump.x, pr.gk_clump.y, clump * clump * (3.0 - 2.0 * clump));
float bw = pr.gk_grow.y * mix(1.0, pr.gk_grow.z * grow, smoothstep(1.0, 4.0, grow));
bw = max(bw, dist * pr.dens.z * 1.1);
uint b = dist < pr.bands.x ? 0u : (dist < pr.bands.y ? 1u : 2u);
uint slot = atomicAdd(cmds[b * 5u + 1u], 1u);
@ -154,6 +160,6 @@ void main() {
uint o = (pr.base[b] + slot) * 4u;
outv[o] = vec4(xz.x, h - 0.02, xz.y, seed);
outv[o + 1u] = vec4(sin(ang), cos(ang), tall, bw);
outv[o + 2u] = vec4(bladeField(xz, h), 0.6 + 0.8 * h4);
outv[o + 2u] = vec4(bladeField(xz, h), pr.gk_clump.z + pr.gk_clump.w * h4);
outv[o + 3u] = vec4(gn, dist);
}