feat(editor): add --gen-texture-clouds sky pattern

Multi-octave cosine-product noise (4 octaves at doubling
frequency, halving amplitude) thresholded by `coverage` so
values above the threshold blend toward cloud color and below
fade to sky. A 0.15-wide smoothstep band feathers cloud edges
instead of stepping hard.

Defaults: coverage=0.5 (mixed clouds), seed=1. Useful for
skybox cubemaps, distant sky planes, atmospheric backdrop
art. Brings the procedural texture pattern set to 25.
This commit is contained in:
Kelsi 2026-05-09 00:20:14 -07:00
parent 3d5a786ca9
commit 08f740a1ff
3 changed files with 107 additions and 0 deletions

View file

@ -1992,6 +1992,107 @@ int handleBark(int& i, int argc, char** argv) {
return 0;
}
int handleClouds(int& i, int argc, char** argv) {
// Sky with puffy clouds. Multi-octave smooth noise (4
// octaves of cosine-product noise at doubling frequencies)
// gives soft cloud blobs; the result is thresholded by
// `coverage` so values above the threshold blend toward
// cloud color, and values below fade smoothly to sky.
std::string outPath = argv[++i];
std::string skyHex = argv[++i];
std::string cloudHex = argv[++i];
uint32_t seed = 1;
float coverage = 0.5f; // 0=clear sky, 1=overcast
int W = 256, H = 256;
if (i + 1 < argc && argv[i + 1][0] != '-') {
try { seed = static_cast<uint32_t>(std::stoul(argv[++i])); } catch (...) {}
}
if (i + 1 < argc && argv[i + 1][0] != '-') {
try { coverage = std::stof(argv[++i]); } catch (...) {}
}
if (i + 1 < argc && argv[i + 1][0] != '-') {
try { W = std::stoi(argv[++i]); } catch (...) {}
}
if (i + 1 < argc && argv[i + 1][0] != '-') {
try { H = std::stoi(argv[++i]); } catch (...) {}
}
if (W < 1 || H < 1 || W > 8192 || H > 8192 ||
coverage < 0.0f || coverage > 1.0f) {
std::fprintf(stderr,
"gen-texture-clouds: invalid dims (W/H 1..8192, coverage 0..1)\n");
return 1;
}
uint8_t sr, sg, sb, cr, cg, cb;
if (!parseHex(skyHex, sr, sg, sb)) {
std::fprintf(stderr,
"gen-texture-clouds: '%s' is not a valid hex color\n",
skyHex.c_str());
return 1;
}
if (!parseHex(cloudHex, cr, cg, cb)) {
std::fprintf(stderr,
"gen-texture-clouds: '%s' is not a valid hex color\n",
cloudHex.c_str());
return 1;
}
float seedF = static_cast<float>(seed);
auto cloudNoise = [&](float x, float y) -> float {
// 4 octaves of sin/cos noise at doubling frequency,
// halving amplitude. Output in 0..1 after normalize.
float n = 0.0f;
float total = 0.0f;
float freq = 0.015f;
float amp = 1.0f;
for (int o = 0; o < 4; ++o) {
n += amp * (0.5f + 0.5f *
std::sin(x * freq + seedF * (1.0f + o * 0.7f)) *
std::cos(y * freq + seedF * (0.5f + o * 0.4f)));
total += amp;
freq *= 2.0f;
amp *= 0.5f;
}
return n / total;
};
std::vector<uint8_t> pixels(static_cast<size_t>(W) * H * 3, 0);
// Coverage maps to a noise threshold: low coverage = high
// threshold (only the brightest noise becomes clouds);
// high coverage = low threshold (more area is cloudy).
float thresh = 1.0f - coverage;
int cloudPixels = 0;
for (int y = 0; y < H; ++y) {
for (int x = 0; x < W; ++x) {
float n = cloudNoise(static_cast<float>(x),
static_cast<float>(y));
// Smooth blend across a 0.15-wide band around the
// threshold so cloud edges feather rather than step.
float t = std::clamp((n - thresh) / 0.15f, 0.0f, 1.0f);
if (t > 0.5f) ++cloudPixels;
uint8_t r = static_cast<uint8_t>(sr * (1 - t) + cr * t);
uint8_t g = static_cast<uint8_t>(sg * (1 - t) + cg * t);
uint8_t b = static_cast<uint8_t>(sb * (1 - t) + cb * t);
size_t i2 = (static_cast<size_t>(y) * W + x) * 3;
pixels[i2 + 0] = r;
pixels[i2 + 1] = g;
pixels[i2 + 2] = b;
}
}
if (!stbi_write_png(outPath.c_str(), W, H, 3,
pixels.data(), W * 3)) {
std::fprintf(stderr,
"gen-texture-clouds: stbi_write_png failed for %s\n",
outPath.c_str());
return 1;
}
std::printf("Wrote %s\n", outPath.c_str());
std::printf(" size : %dx%d\n", W, H);
std::printf(" sky/cloud : %s / %s\n",
skyHex.c_str(), cloudHex.c_str());
std::printf(" coverage : %.2f (%d cloud pixels)\n",
coverage, cloudPixels);
std::printf(" seed : %u\n", seed);
return 0;
}
} // namespace
bool handleGenTexture(int& i, int argc, char** argv, int& outRc) {
@ -2060,6 +2161,9 @@ bool handleGenTexture(int& i, int argc, char** argv, int& outRc) {
if (std::strcmp(argv[i], "--gen-texture-bark") == 0 && i + 3 < argc) {
outRc = handleBark(i, argc, argv); return true;
}
if (std::strcmp(argv[i], "--gen-texture-clouds") == 0 && i + 3 < argc) {
outRc = handleClouds(i, argc, argv); return true;
}
return false;
}

View file

@ -77,6 +77,8 @@ void printUsage(const char* argv0) {
std::printf(" Square stone tiles with grout grid (default 32px tiles, 2px grout)\n");
std::printf(" --gen-texture-bark <out.png> <baseHex> <crackHex> [seed] [crackDensity] [W H]\n");
std::printf(" Tree bark: vertical wavy streaks + dark vertical cracks (default density=0.04)\n");
std::printf(" --gen-texture-clouds <out.png> <skyHex> <cloudHex> [seed] [coverage] [W H]\n");
std::printf(" Sky with puffy clouds: multi-octave noise thresholded by coverage (default 0.5)\n");
std::printf(" --add-texture-to-zone <zoneDir> <png-path> [renameTo]\n");
std::printf(" Copy an existing PNG into <zoneDir> (optionally renaming it on the way in)\n");
std::printf(" --gen-mesh <wom-base> <cube|plane|sphere|cylinder|torus|cone|ramp> [size]\n");

View file

@ -573,6 +573,7 @@ int main(int argc, char* argv[]) {
"--gen-texture-cobble", "--gen-texture-marble", "--gen-texture-metal",
"--gen-texture-leather", "--gen-texture-sand", "--gen-texture-snow",
"--gen-texture-lava", "--gen-texture-tile", "--gen-texture-bark",
"--gen-texture-clouds",
"--validate-glb", "--info-glb", "--info-glb-tree", "--info-glb-bytes",
"--validate-jsondbc", "--check-glb-bounds", "--validate-stl",
"--validate-png", "--validate-blp",