feat(editor): add --gen-texture-stars night-sky pattern

Solid background fill plus randomly placed stars at varied
brightness — most stars dim (30-65% blend toward star color),
occasional bright stars (85-100% blend) — so the sky reads
with depth rather than as uniform noise. Exit log breaks down
how many bright vs faint stars actually landed.

Defaults: density=0.005 (~0.5% of pixels become stars), seed=1.
Useful for skybox top-faces, distant night sky planes, magical
constellation set dressing. Brings the procedural texture
pattern set to 26.
This commit is contained in:
Kelsi 2026-05-09 01:32:08 -07:00
parent efe0a91335
commit 2d81bc9f6b
3 changed files with 96 additions and 1 deletions

View file

@ -2093,6 +2093,96 @@ int handleClouds(int& i, int argc, char** argv) {
return 0;
}
int handleStars(int& i, int argc, char** argv) {
// Night sky: solid background color sprinkled with bright
// stars at random positions and varied per-star brightness
// (so the sky has a depth feel — bright nearby stars + dim
// distant ones). Density controls roughly what fraction of
// pixels become stars.
std::string outPath = argv[++i];
std::string bgHex = argv[++i];
std::string starHex = argv[++i];
uint32_t seed = 1;
float density = 0.005f;
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 { density = 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 ||
density < 0.0f || density > 1.0f) {
std::fprintf(stderr,
"gen-texture-stars: invalid dims (W/H 1..8192, density 0..1)\n");
return 1;
}
uint8_t br, bg, bb_, sr, sg, sb;
if (!parseHex(bgHex, br, bg, bb_)) {
std::fprintf(stderr,
"gen-texture-stars: '%s' is not a valid hex color\n",
bgHex.c_str());
return 1;
}
if (!parseHex(starHex, sr, sg, sb)) {
std::fprintf(stderr,
"gen-texture-stars: '%s' is not a valid hex color\n",
starHex.c_str());
return 1;
}
std::vector<uint8_t> pixels(static_cast<size_t>(W) * H * 3, 0);
// Background: flat fill.
for (int p = 0; p < W * H; ++p) {
size_t i2 = static_cast<size_t>(p) * 3;
pixels[i2 + 0] = br;
pixels[i2 + 1] = bg;
pixels[i2 + 2] = bb_;
}
uint32_t state = seed ? seed : 1u;
auto next01 = [&state]() -> float {
state = state * 1664525u + 1013904223u;
return (state >> 8) * (1.0f / 16777216.0f);
};
int starCount = static_cast<int>(W * H * density);
int bright = 0, faint = 0;
for (int s = 0; s < starCount; ++s) {
int sx = static_cast<int>(next01() * W);
int sy = static_cast<int>(next01() * H);
// Brightness: weighted toward dim stars (most stars at
// 30..60% blend, occasional bright at 100%). Keeps the
// texture from looking like equally-bright pixel noise.
float r = next01();
float t = (r < 0.85f) ? (0.3f + r * 0.35f) : (0.85f + r * 0.15f);
if (t > 0.7f) ++bright; else ++faint;
size_t i2 = (static_cast<size_t>(sy) * W + sx) * 3;
pixels[i2 + 0] = static_cast<uint8_t>(br * (1 - t) + sr * t);
pixels[i2 + 1] = static_cast<uint8_t>(bg * (1 - t) + sg * t);
pixels[i2 + 2] = static_cast<uint8_t>(bb_ * (1 - t) + sb * t);
}
if (!stbi_write_png(outPath.c_str(), W, H, 3,
pixels.data(), W * 3)) {
std::fprintf(stderr,
"gen-texture-stars: 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(" bg/star : %s / %s\n",
bgHex.c_str(), starHex.c_str());
std::printf(" density : %.4f\n", density);
std::printf(" stars : %d (%d bright, %d faint)\n",
starCount, bright, faint);
std::printf(" seed : %u\n", seed);
return 0;
}
} // namespace
bool handleGenTexture(int& i, int argc, char** argv, int& outRc) {
@ -2164,6 +2254,9 @@ bool handleGenTexture(int& i, int argc, char** argv, int& outRc) {
if (std::strcmp(argv[i], "--gen-texture-clouds") == 0 && i + 3 < argc) {
outRc = handleClouds(i, argc, argv); return true;
}
if (std::strcmp(argv[i], "--gen-texture-stars") == 0 && i + 3 < argc) {
outRc = handleStars(i, argc, argv); return true;
}
return false;
}

View file

@ -79,6 +79,8 @@ void printUsage(const char* argv0) {
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(" --gen-texture-stars <out.png> <bgHex> <starHex> [seed] [density] [W H]\n");
std::printf(" Night sky with scattered stars (varied brightness, density 0..1, default 0.005)\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

@ -575,7 +575,7 @@ 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",
"--gen-texture-clouds", "--gen-texture-stars",
"--validate-glb", "--info-glb", "--info-glb-tree", "--info-glb-bytes",
"--validate-jsondbc", "--check-glb-bounds", "--validate-stl",
"--validate-png", "--validate-blp",