From 3770b101cfc5ad37a069850b422f0098ade7fc08 Mon Sep 17 00:00:00 2001 From: Dan Goodliffe Date: Thu, 22 Feb 2024 01:16:29 +0000 Subject: First cut of terrain deformation This "works" for some definition of works... But it's flawed in many ways, not least the following: * It's glitchy for no obvious reason * It's unreliable; fails if you tweak the parameters * The sides of the modified area are triangulated in the dumbest possible fashion, which results in ill-formed polygons * Probably other things, but... It works, remember... --- game/geoData.cpp | 166 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ game/geoData.h | 2 + 2 files changed, 168 insertions(+) (limited to 'game') diff --git a/game/geoData.cpp b/game/geoData.cpp index 0dbc0ac..86b9152 100644 --- a/game/geoData.cpp +++ b/game/geoData.cpp @@ -1,7 +1,10 @@ #include "geoData.h" +#include "collections.h" #include #include +#include #include +#include GeoData GeoData::loadFromAsciiGrid(const std::filesystem::path & input) @@ -375,3 +378,166 @@ GeoData::triangleContainsTriangle(const Triangle<2> & a, const Triangle<2> & b) { return triangleContainsPoint(a.x, b) && triangleContainsPoint(a.y, b) && triangleContainsPoint(a.z, b); } + +void +GeoData::setHeights(const std::span triangleStrip) +{ + std::set nosplit; + // Create new vertices + std::vector newVerts; + newVerts.reserve(newVerts.size()); + std::transform(triangleStrip.begin(), triangleStrip.end(), std::back_inserter(newVerts), [this](const auto tsVert) { + return add_vertex(tsVert); + }); + // Create new faces + std::vector newFaces; + newFaces.reserve(newVerts.size() - 2); + std::transform(strip_begin(newVerts), strip_end(newVerts), std::back_inserter(newFaces), + [this, &nosplit](const auto & newVert) { + const auto [a, b, c] = newVert; + auto faceHandle = add_face(a, b, c); + std::copy(fe_begin(faceHandle), fe_end(faceHandle), std::inserter(nosplit, nosplit.end())); + return faceHandle; + }); + std::vector boundary; + boundaryWalk( + [out = std::back_inserter(boundary)](const auto boundaryHeh) mutable { + out = boundaryHeh; + }, + *voh_begin(newVerts.front())); + + // Extrude corners + std::set cutpoints; + std::vector> extrusionExtents; + std::vector extrusionVertices; + std::transform(boundary.begin(), boundary.end(), std::back_inserter(extrusionExtents), + [this, &nosplit, &cutpoints, &extrusionVertices](const auto boundaryHeh) { + const auto vectorNormal + = [](const glm::vec<2, T, Q> & v) -> glm::vec<2, T, Q> { + return {-v.y, v.x}; + }; + + const auto p0 = point(from_vertex_handle(prev_halfedge_handle(boundaryHeh))); + const auto p1 = point(from_vertex_handle(boundaryHeh)); + const auto p2 = point(to_vertex_handle(boundaryHeh)); + const auto e0 = glm::normalize(vectorNormal(RelativePosition2D(p1 - p0))); + const auto e1 = glm::normalize(vectorNormal(RelativePosition2D(p2 - p1))); + const auto mid = glm::normalize((e0 + e1) / 2.F); + const auto doExtrusion = [mid, p1, this, &nosplit, &cutpoints, &extrusionVertices]( + RelativeDistance vert, GlobalDistance limit) { + const auto extrusionDir = glm::normalize(mid || vert); + + if (const auto intersect = intersectRay({p1, extrusionDir})) { + auto splitVertex = split(intersect->second, intersect->first); + cutpoints.insert(splitVertex); + extrusionVertices.push_back(splitVertex); + std::copy(ve_begin(splitVertex), ve_end(splitVertex), std::inserter(nosplit, nosplit.end())); + } + + const auto extrusion + = extrusionDir * std::max(0.F, RelativeDistance(limit - p1.z) / extrusionDir.z); + return p1 + GlobalPosition3D(extrusion); + }; + return std::make_pair(doExtrusion(-2, lowerExtent.z - 100), doExtrusion(2, upperExtent.z + 100)); + }); + + // Cut existing terrain + extrusionExtents.emplace_back(extrusionExtents.front()); // Circular next + extrusionVertices.emplace_back(extrusionVertices.front()); + std::vector> boundaryFaces; + std::transform(boundary.begin(), boundary.end(), std ::back_inserter(boundaryFaces), + [ex = extrusionExtents.begin(), exv = extrusionVertices.begin(), this, &nosplit]( + const auto boundaryHeh) mutable { + const auto fromVertex = from_vertex_handle(boundaryHeh); + const auto p0 = point(fromVertex); + auto toVertex = to_vertex_handle(boundaryHeh); + const auto p1 = point(toVertex); + const auto nex = ex + 1; + const auto nexv = exv + 1; + const std::array, 4> triangles {{ + {p0, ex->first, nex->first}, + {p0, p1, nex->first}, + {p0, ex->second, nex->second}, + {p0, p1, nex->second}, + }}; + + std::vector sideVerts {fromVertex, *exv}; + for (auto currentVertex = *exv; + std::any_of(voh_begin(currentVertex), voh_end(currentVertex), [&](const auto currentVertexOut) { + const auto next = next_halfedge_handle(currentVertexOut); + const auto nextVertex = to_vertex_handle(next); + const auto startVertex = from_vertex_handle(next); + if (nextVertex == *++sideVerts.rbegin()) { + // This half edge goes back to the previous vertex + return false; + } + if (nextVertex == *nexv) { + // The next half edge goes to the termination point + return false; + } + const auto edge = edge_handle(next); + if (nosplit.contains(edge)) { + // This edge should not be split (for some reason, maybe no longer applies) + return false; + } + const auto ep0 = point(startVertex); + const auto ep1 = point(nextVertex); + const auto diff = RelativePosition3D(ep1 - ep0); + const auto length = glm::length(diff); + const auto dir = diff / length; + const Ray r {ep0, dir}; + return std::any_of(triangles.begin(), triangles.end(), [&](const auto & triangle) { + BaryPosition bary; + RelativeDistance dist {}; + + if (r.intersectTriangle(triangle.x, triangle.y, triangle.z, bary, dist) + && dist <= length - 1 && dist >= 1) { + const auto splitPos = triangle * bary; + currentVertex = sideVerts.emplace_back(split(edge, splitPos)); + return true; + } + return false; + }); + });) { + ; + } + sideVerts.emplace_back(*nexv); + sideVerts.emplace_back(toVertex); + ex = nex; + exv++; + return sideVerts; + }); + + // Remove old faces + std::set visited; + auto removeOld = [&](auto & self, const auto face) -> void { + if (visited.insert(face).second) { + std::vector neighbourFaces; + std::for_each(fh_begin(face), fh_end(face), [&](const auto fh) { + if (std::none_of(boundaryFaces.begin(), boundaryFaces.end(), [fh, this](const auto & bf) { + return std::find(bf.begin(), bf.end(), from_vertex_handle(fh)) != bf.end() + && std::find(bf.begin(), bf.end(), to_vertex_handle(fh)) != bf.end(); + })) { + neighbourFaces.emplace_back(opposite_face_handle(fh)); + } + }); + + delete_face(face, false); + std::for_each(neighbourFaces.begin(), neighbourFaces.end(), [&self](const auto nextFace) { + if (nextFace.is_valid()) { + self(self, nextFace); + } + }); + } + }; + removeOld(removeOld, findPoint(triangleStrip.front())); + + std::for_each(boundaryFaces.begin(), boundaryFaces.end(), [&](auto & boundaryFace) { + std::reverse(boundaryFace.begin(), boundaryFace.end()); + add_face(boundaryFace); + }); + + // Tidy up + garbage_collection(); + update_vertex_normals_only(); +} diff --git a/game/geoData.h b/game/geoData.h index 6c6ae26..4d8e11c 100644 --- a/game/geoData.h +++ b/game/geoData.h @@ -89,6 +89,8 @@ public: [[nodiscard]] HalfedgeHandle findEntry(const GlobalPosition2D from, const GlobalPosition2D to) const; + void setHeights(const std::span triangleStrip); + [[nodiscard]] auto getExtents() const { -- cgit v1.2.3