From ca8c36687025436527e96919f2d86e9a464490e1 Mon Sep 17 00:00:00 2001 From: Kelsi Date: Thu, 7 May 2026 08:46:50 -0700 Subject: [PATCH] feat(editor): add --export-mesh-heightmap, inverse of gen-mesh-from-heightmap MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Extracts a grayscale heightmap PNG from a row-major W×H heightmap mesh. Y values are normalized to 0..255 using the mesh bounds so the output PNG uses the full dynamic range. User supplies W and H explicitly: arbitrary meshes aren't necessarily heightmap-shaped, and taking the dimensions as args avoids guessing wrong on a mesh with vertex count W*H but a different layout. Round-trips with --gen-mesh-from-heightmap modulo the 1-byte quantization step. Verified: noise PNG (32×32) → heightmap mesh → exported PNG (32×32) chain executes cleanly, height 0..1.984 mapped to 0..255 grayscale, both PNGs share the same dimensions. Brings command count to 230. --- tools/editor/main.cpp | 88 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 87 insertions(+), 1 deletion(-) diff --git a/tools/editor/main.cpp b/tools/editor/main.cpp index c4633c76..580f54f7 100644 --- a/tools/editor/main.cpp +++ b/tools/editor/main.cpp @@ -545,6 +545,8 @@ static void printUsage(const char* argv0) { std::printf(" Procedural straight staircase along +X with N steps (default 5 / 0.2 / 0.3 / 1.0)\n"); std::printf(" --gen-mesh-from-heightmap [scaleXZ] [scaleY]\n"); std::printf(" Convert a grayscale PNG into a heightmap mesh (W×H verts, 2(W-1)(H-1) tris)\n"); + std::printf(" --export-mesh-heightmap \n"); + std::printf(" Extract a grayscale heightmap PNG from a row-major W×H heightmap mesh\n"); std::printf(" --add-texture-to-mesh [batchIdx]\n"); std::printf(" Bind an existing PNG into a WOM's texturePaths and point batchIdx (default 0) at it\n"); std::printf(" --scale-mesh \n"); @@ -984,7 +986,7 @@ int main(int argc, char* argv[]) { "--export-data-tree-md", "--gen-texture", "--gen-mesh", "--gen-mesh-textured", "--add-texture-to-mesh", "--add-texture-to-zone", "--gen-mesh-stairs", "--gen-texture-gradient", - "--gen-mesh-from-heightmap", + "--gen-mesh-from-heightmap", "--export-mesh-heightmap", "--scale-mesh", "--translate-mesh", "--strip-mesh", "--gen-texture-noise", "--rotate-mesh", "--center-mesh", "--flip-mesh-normals", "--mirror-mesh", @@ -16654,6 +16656,90 @@ int main(int argc, char* argv[]) { std::printf(" vertices : %zu\n", wom.vertices.size()); std::printf(" triangles : %zu\n", wom.indices.size() / 3); return 0; + } else if (std::strcmp(argv[i], "--export-mesh-heightmap") == 0 && i + 4 < argc) { + // Inverse of --gen-mesh-from-heightmap: extract a + // grayscale PNG from a row-major W×H heightmap mesh. + // The user supplies W and H since arbitrary meshes + // aren't necessarily heightmap-shaped — taking the + // dimensions explicitly avoids guessing wrong on a + // mesh with vertex count W*H but a different layout. + // + // Y values are normalized to 0..255 using the mesh + // bounds (Y_min → 0, Y_max → 255). Round-trips with + // --gen-mesh-from-heightmap modulo the 1-byte + // quantization step. + std::string womBase = argv[++i]; + std::string outPath = argv[++i]; + int W = 0, H = 0; + try { + W = std::stoi(argv[++i]); + H = std::stoi(argv[++i]); + } catch (...) { + std::fprintf(stderr, + "export-mesh-heightmap: W and H must be integers\n"); + return 1; + } + if (W < 2 || H < 2 || W > 8192 || H > 8192) { + std::fprintf(stderr, + "export-mesh-heightmap: W and H must be 2..8192\n"); + return 1; + } + if (womBase.size() >= 4 && + womBase.substr(womBase.size() - 4) == ".wom") { + womBase = womBase.substr(0, womBase.size() - 4); + } + if (!wowee::pipeline::WoweeModelLoader::exists(womBase)) { + std::fprintf(stderr, + "export-mesh-heightmap: %s.wom does not exist\n", + womBase.c_str()); + return 1; + } + auto wom = wowee::pipeline::WoweeModelLoader::load(womBase); + if (!wom.isValid()) { + std::fprintf(stderr, + "export-mesh-heightmap: failed to load %s.wom\n", + womBase.c_str()); + return 1; + } + size_t expected = static_cast(W) * H; + if (wom.vertices.size() < expected) { + std::fprintf(stderr, + "export-mesh-heightmap: %s.wom has %zu vertices, " + "need at least %zu for %dx%d\n", + womBase.c_str(), wom.vertices.size(), expected, W, H); + return 1; + } + float yMin = wom.boundMin.y; + float yMax = wom.boundMax.y; + float range = yMax - yMin; + std::vector pixels(expected * 3, 0); + for (int y = 0; y < H; ++y) { + for (int x = 0; x < W; ++x) { + size_t idx = static_cast(y) * W + x; + float h = wom.vertices[idx].position.y; + float t = (range > 1e-6f) ? (h - yMin) / range : 0.0f; + if (t < 0) t = 0; if (t > 1) t = 1; + uint8_t g = static_cast(t * 255.0f + 0.5f); + size_t i2 = idx * 3; + pixels[i2 + 0] = g; + pixels[i2 + 1] = g; + pixels[i2 + 2] = g; + } + } + if (!stbi_write_png(outPath.c_str(), W, H, 3, + pixels.data(), W * 3)) { + std::fprintf(stderr, + "export-mesh-heightmap: stbi_write_png failed for %s\n", + outPath.c_str()); + return 1; + } + std::printf("Wrote %s from %s.wom\n", + outPath.c_str(), womBase.c_str()); + std::printf(" size : %dx%d\n", W, H); + std::printf(" height : %.3f to %.3f (mapped to 0..255)\n", + yMin, yMax); + std::printf(" pixels : %zu (W*H)\n", expected); + return 0; } else if (std::strcmp(argv[i], "--add-texture-to-mesh") == 0 && i + 2 < argc) { // Manual companion to --gen-mesh-textured. Binds an // existing PNG to a WOM by appending it to texturePaths