feat(editor): add --gen-texture-radial for circular gradients

Synthesizes a radial gradient PNG fading from <centerHex> at the
image center to <edgeHex> at the corner. Distance is normalized so
the corner is t=1 (works for non-square images), with a smoothstep
curve giving a soft falloff rather than a harsh disc edge.

Useful for spell glow rings, vignettes, soft-edged decals, and
particle-emitter masks — the common "circular blob" cases that
linear gradients can't produce.

Verified: 64×64 white-center / black-edge "glow" PNG written
successfully; invalid 'notacolor' hex rejected with exit 1.
Brings command count to 222.
This commit is contained in:
Kelsi 2026-05-07 07:00:05 -07:00
parent 2cb079549e
commit a3253eebc6

View file

@ -530,6 +530,8 @@ static void printUsage(const char* argv0) {
std::printf(" Synthesize a linear gradient PNG (default vertical, 256x256)\n");
std::printf(" --gen-texture-noise <out.png> [seed] [W H]\n");
std::printf(" Synthesize a smooth value-noise PNG (deterministic from seed; default 256x256)\n");
std::printf(" --gen-texture-radial <out.png> <centerHex> <edgeHex> [W H]\n");
std::printf(" Synthesize a radial gradient PNG (center→edge, smooth distance-based blend)\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> [size]\n");
@ -970,6 +972,7 @@ int main(int argc, char* argv[]) {
"--scale-mesh", "--translate-mesh", "--strip-mesh",
"--gen-texture-noise", "--rotate-mesh",
"--center-mesh", "--flip-mesh-normals",
"--gen-texture-radial",
"--validate-glb", "--info-glb", "--info-glb-tree", "--info-glb-bytes",
"--validate-jsondbc", "--check-glb-bounds", "--validate-stl",
"--validate-png", "--validate-blp",
@ -15569,6 +15572,115 @@ int main(int argc, char* argv[]) {
std::printf(" seed : %u\n", seed);
std::printf(" type : smooth value noise (16x16 bilinear lattice)\n");
return 0;
} else if (std::strcmp(argv[i], "--gen-texture-radial") == 0 && i + 3 < argc) {
// Radial gradient: centerHex at the image center fading
// smoothly to edgeHex at the corner. Useful for spell
// glow rings, vignettes, soft-edged decals — the
// common "circular blob" cases that linear gradients
// can't produce.
//
// Distance is normalized so the corner is t=1 (image is
// not necessarily square). A smoothstep curve gives a
// soft falloff rather than a harsh disc edge.
std::string outPath = argv[++i];
std::string centerHex = argv[++i];
std::string edgeHex = argv[++i];
int W = 256, H = 256;
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) {
std::fprintf(stderr,
"gen-texture-radial: invalid size %dx%d (1..8192)\n",
W, H);
return 1;
}
auto parseHex = [](std::string hex,
uint8_t& r, uint8_t& g, uint8_t& b) -> bool {
std::transform(hex.begin(), hex.end(), hex.begin(),
[](unsigned char c) { return std::tolower(c); });
if (!hex.empty() && hex[0] == '#') hex.erase(0, 1);
auto fromHexC = [](char c) -> int {
if (c >= '0' && c <= '9') return c - '0';
if (c >= 'a' && c <= 'f') return 10 + c - 'a';
return -1;
};
int v[6];
if (hex.size() == 6) {
for (int k = 0; k < 6; ++k) {
v[k] = fromHexC(hex[k]);
if (v[k] < 0) return false;
}
r = static_cast<uint8_t>((v[0] << 4) | v[1]);
g = static_cast<uint8_t>((v[2] << 4) | v[3]);
b = static_cast<uint8_t>((v[4] << 4) | v[5]);
return true;
}
if (hex.size() == 3) {
for (int k = 0; k < 3; ++k) {
v[k] = fromHexC(hex[k]);
if (v[k] < 0) return false;
}
r = static_cast<uint8_t>((v[0] << 4) | v[0]);
g = static_cast<uint8_t>((v[1] << 4) | v[1]);
b = static_cast<uint8_t>((v[2] << 4) | v[2]);
return true;
}
return false;
};
uint8_t rc, gc, bc, re, ge, be;
if (!parseHex(centerHex, rc, gc, bc)) {
std::fprintf(stderr,
"gen-texture-radial: '%s' is not a valid hex color\n",
centerHex.c_str());
return 1;
}
if (!parseHex(edgeHex, re, ge, be)) {
std::fprintf(stderr,
"gen-texture-radial: '%s' is not a valid hex color\n",
edgeHex.c_str());
return 1;
}
std::vector<uint8_t> pixels(static_cast<size_t>(W) * H * 3, 0);
float cx = (W - 1) * 0.5f;
float cy = (H - 1) * 0.5f;
// Max distance is the corner (cx, cy itself = half-diag).
float maxD = std::sqrt(cx * cx + cy * cy);
for (int y = 0; y < H; ++y) {
for (int x = 0; x < W; ++x) {
float dx = x - cx;
float dy = y - cy;
float d = std::sqrt(dx * dx + dy * dy);
float t = (maxD > 0) ? (d / maxD) : 0.0f;
if (t > 1.0f) t = 1.0f;
// Smoothstep so the falloff is soft.
float smt = t * t * (3.0f - 2.0f * t);
auto lerp = [](uint8_t a, uint8_t b, float t) {
return static_cast<uint8_t>(a + (b - a) * t + 0.5f);
};
size_t i2 = (static_cast<size_t>(y) * W + x) * 3;
pixels[i2 + 0] = lerp(rc, re, smt);
pixels[i2 + 1] = lerp(gc, ge, smt);
pixels[i2 + 2] = lerp(bc, be, smt);
}
}
if (!stbi_write_png(outPath.c_str(), W, H, 3,
pixels.data(), W * 3)) {
std::fprintf(stderr,
"gen-texture-radial: 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(" center : %s (rgb %u,%u,%u)\n",
centerHex.c_str(), rc, gc, bc);
std::printf(" edge : %s (rgb %u,%u,%u)\n",
edgeHex.c_str(), re, ge, be);
return 0;
} else if (std::strcmp(argv[i], "--gen-mesh") == 0 && i + 2 < argc) {
// Synthesize a procedural primitive WOM. Generates proper
// per-face normals, planar UVs, a bounding box, and a